Nuclear Physics in Astrophysics VIII

18 Jun 2017, 08:00 → 23 Jun 2017, 18:00 Europe/Rome

Sala conferenze (Laboratori Nazionali del Sud)

Claudio Spitaleri (LNS), Marcello Lattuada (LNS)

The 8th Nuclear Physics in Astrophysics International conference will be held from June 18th through June 23rd, 2017 in Catania, Italy.

NPA8 is supported by the European Physical Society

                      
by the Istituto Nazionale di Fisica Nucleare 

               

and by the Department of Physics and Astronomy of the University of Catania
              

We also acknowledge the support of:
         

          

        

Paper BOOK OF ABSTRACT npa8_abstract.tex

Poster NPA8locandina_corretta.pdf

Sunday, 18 June ¶

18:00 Welcome cocktail

Monday, 19 June ¶

Welcome address¶

Explosive nucleosynthesis observations¶

1 When Stars Attack! Live Radioisotopes Reveal Near-Earth Supernovae¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in \def\iso#1#2{\mbox{$\text{You can't use 'macro parameter character \#' in math mode}$}} \def\fe6#1{\iso{Fe}{6#1}} %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Prof. Brian Fields (Departments of Astronomy and of Physics, University of Illinois)

Slides Fields.pdf

2 60Fe and 244Pu in deep-sea archives - a link to nearby supernova activity and r–process sites¶

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Speaker: Prof. Anton Wallner (The Australian National University)

Slides Wallner.pdf

3 Recent Ultra High Energy neutrino bounds and multimessenger observations with the Pierre Auger Observatory¶

The overall picture of the highest energy particles produced in the Universe is changing because of measurements made with the Pierre Auger Observatory. Composition studies point towards an unexpected mixed composition of intermediate mass nuclei, more isotropic than anticipated, which is reshaping the future of the field and underlining the priority to understand composition at the highest energies. The Observatory is competitive in the search for neutrinos of all flavours above about 100 PeV by looking for very inclined showers produced deep in the atmosphere by neutrinos interacting either in the atmosphere or in the Earth's crust and covering a declination field of view between $-{65}^{\circ }$ and ${60}^{\circ }$ in equatorial coordinates. ​​Neutrinos are produced in ultra high energy cosmic ray ​interactions and they provide valuable complementary information, their fluxes being sensitive to the primary cosmic ray masses and their directions reflecting the source positions. We report the results of the neutrino search providing competitive bounds to neutrino production and strong constraints to a number of production models including cosmogenic neutrinos due to ultra high energy protons. We also report on two recent contributions of the Observatory to multimessenger studies​.​ The correlations of the directions of the highest energy astrophysical neutrinos discovered with IceCube ​and​ the highest energy cosmic rays detected with the Auger Observatory and the Telescope Array​,​ and the targeted search for neutrinos correlated with the discovery of the gravitational​-​wave events GW150914 and GW151226 ​discovered ​with ​​advanced LIGO.

Speaker: Prof. Enrique Zas (IGFAE - University of Santiago)

Slides Zas.pdf

4 Limits on 60Fe/26Al nucleosynthesis ratios from deep-sea sediment AMS measurements¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Jenny Feige (Berlin Institute of Technology)

11:20 Coffee break

r-process 1¶

5 Explosive nucleosynthesis of heavy elements: an astrophysical and nuclear physics challenge¶

Half of the elements heavier than iron are produced by the r process under extreme conditions. To identify its site remains one of the major challenges in nuclear astrophysics. Advances in the description of neutrino-matter interactions and its implementation in core-collapse super- nova modelling have lead to the conclusion that supernova explosions only contribute to the production of elements with Z < 50. Compact binary mergers are currently considered the best candidate for the main r-process site. These events are expected to produce gravitational waves, likely to be observed by the LIGO collaboration, and eject large amounts of neutron-rich mate- rial where the r process operates. In this talk, I will discuss the important role of nuclear physics to determine the r-process yields from compact binary mergers. In addition to neutron captures and beta decay, fission rates and yields of superheavy neutron-rich nuclei are fundamental to un- derstand the r-process dynamics and nucleosynthesis. Mergers constitute also ideal candidates to directly observe the r-process via an electromagnetic transient due to the radioactive decay of r-process material. This type of event, known as kilonova, may have already been observed associated with the gamma-ray burst GRB 130603B.

Speaker: Prof. Gabriel Martínez Pinedo (Technische Universität Darmstadt)

6 Solving the mystery of r-process: mergers vs. supernovae¶

Taka Kajino, Shota Shibagaki, Yutaka Hirai, Grant J. Mathews The origin of heavy elements heavier than iron like Au and U are still unknown although sixty years have already passed since the benchmark paper B2FH on the origin of elements in the Universe was published in 1957. GW emitters of both binary neutron-star mergers (NSMs) and core-collapse supernovae (SNe) are viable candidates for the production site of heavy elements called r-process elements. SN models of magneto-rotationally driven jets (MHD-Jet SNe) naturally explain the ”universality” in the observed abundance pattern between the solar- system and extremely metal-poor stars in the Milky Way halo or recently discovered ultra-faint dwarf galaxies. However, full understanding of their explosion mechanism is still in progress. NSM models, on the other hand, have a serious difficulty that their arrival is delayed due to very slow GW radiation at least 100 My (”time-scale problem”), which could not contribute to the early galaxies. We will first discuss that our high-resolution N-body/SPH simulation of Galactic chemo-dynamical evolution solve this ”time-scale problem” partially, leaving a serious discrepancy in the early Galactic evolution [1,2]. We will then propose a new theoretical model such that the MHD-Jet SNe first contribute to the enrichment of heavy elements in the early galaxies, then the NSMs follow gradually towards the solar system [3-5]. Our new model satisfies the ”universality” and predicts several specific observational evidences for the time evolution of isotopic abundance pattern [5]. [1] Y. Hirai, Y. Ishimaru, T. R. Saitoh, M. S. Fujii, J. Hidaka, and T. Kajino, ApJ 814 (2015), 4. [2] Y. Hirai, Y. Ishimaru, T. R. Saitoh, M. S. Fujii, J. Hidaka, and T. Kajino, MNRAS 466 (2017) 2472. [3] S. Shibagaki, T. Kajino, G. J. Mathews, S. Chiba, S. Nishimura, and G. Lorusso, ApJ 816 (2016) 79. [4] S. Shibagaki, et al. (2017) to be submitted. [5] T. Kajino, and G. J. Mathews, Rep. Prog. Phys. (2017) in press.

Speaker: Prof. Taka Kajino (NAOJ, The University of Tokyo)

7 The neutrino process in supernova nucleosynthesis¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Mr Andre Sieverding (Technische Universität Darmstadt)

Slides Sieverding.pdf

8 Roles of nuclear weak rates on the evolution of degenerate cores in stars¶

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Speaker: Prof. Toshio Suzuki (Nihon University)

Slides Suzuki.pdf

13:30 Lunch

r-process 2¶

9 The r-process nucleosynthesis and related nuclear challenges¶

The r-process nucleosynthesis and related nuclear challenges S. Goriely Institut d’Astronomie et d’Astrophysique, Université Libre de Bruxelles, Belgium Contact email: sgoriely@astro.ulb.ac.be The rapid neutron-capture process, or r-process, is known to be of fundamental importance for explaining the origin of approximately half of the A > 60 stable nuclei observed in nature. In recent years nuclear astrophysicists have developed more and more sophisticated r-process models, eagerly trying to add new astrophysical or nuclear physics ingredients to explain the solar system composition in a satisfactory way. Recently, special attention has been paid to neutron star (NS) mergers following the confirmation by hydrodynamic simulations that a non- negligible amount of matter can be ejected and by nucleosynthesis calculations combined with the predicted astrophysical event rate that such events can account for the majority of r-material in our Galaxy We show here that the combined contribution of both the dynamical (prompt) ejecta expelled during binary NS or NS-black hole (BH) mergers and the neutrino and viscously driven outflows generated during the post-merger remnant evolution of relic BH-torus systems can lead to the production of r-process elements from mass number A >∼ 90 up to thorium and uranium. The corresponding abundance distribution is found to reproduce the solar distribution extremely well and can also account for the elemental distributions observed in low-metallicity stars. However, major uncertainties still affect our understanding of the composition of the matter ejected. These concern (i) the β-interactions of electron neutrinos and electron antineutrinos with free neutrons and protons, as well as their inverse reactions, which may affect the neutron-richness of the matter at the early phase of the ejection, and (ii) the nuclear physics of exotic neutron-rich nuclei, including nuclear structure as well as nuclear interaction properties, which impact the calculated abundance distribution resulting from the r-process nucleosynthesis. Both aspects will be critically discussed in the light of recent hydrodynamical simulations of NS mergers and microscopic calculations of nuclear decay and reaction probabilities.

Speaker: Stephane Goriely (Universite Libre de Bruxelles)

10 Three-body radiative capture reactions¶

(file)

Speaker: Dr Jesús Casal (ECT*)

11 Effect of uncertainties in the statistical model description of n,γ reactions to r-process nucleosynthesis¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Georgios Perdikakis (Central Michigan University)

12 Constraining the rp-process by measuring 23Al(d,n)24Si with GRETINA and LENDA at NSCL¶

The ${}^{23}$Al(p,$\gamma$)${}^{24}$Si stellar reaction rate has a significant impact of the light-curve emitted in X-ray bursts. Theoretical calculation shows that the reaction rate is mainly determined by the properties of direct capture as well as low-lying 2${}^{+}$ states and a possible 4${}^{+}$ state in ${}^{24}$Si. Currently, there is little experimental information on the properties of these states. We present a new experimental study, using surrogate reaction ${}^{23}$Al(d,n) at 47 AMeV at the National Superconducting Cyclotron Laboratory (NSCL),USA. We detect the full kinematics of the reaction, using the Gamma-Ray Energy Tracking In-beam Nuclear Array (GRETINA) to detect the $\gamma$-rays following the de-excitation of the reaction products, the Low Energy Neutron Detector Array (LENDA) to detect the recoiling neutrons and the S800 for identification of the ${}^{24}$Si recoils. These information will be used to determine the highly needed properties of the ${}^{24}$Si. \\ This work benefited from support by the National Science Foundation under Grant No. PHY-1430152 (JINA Center for the Evolution of the Elements). The research leading to these results has received funding from the European Research Council under the European Unions's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement n. 615126. GRETINA was funded by the DOE, Office of Science. Operation of the array at NSCL was supported by DOE under Grant No. DE-SC0014537 (NSCL) and DE-AC02-05CH11231 (LBNL). This work were supported in part by the National Science foundation under Contract No. PHY-1102511.

Speaker: Clemens Wolf (Goethe-University Frankfurt)

16:00 Coffee break

Direct measurements 1¶

13 EXPERIMENTAL CHALLENGES IN UNDERGROUND NUCLEAR ASTROPHYSICS LABORATORY: PRESENT STATUS AND FUTURE OPPORTUNITIES¶

Accurate knowledge of thermonuclear reaction rates is important in understanding energy generation, neutrino luminosity and nucleosynthesis in stellar interiors. Natural and Cosmic-ray-induced background can seriously limit the determination of reaction cross-sections at relevant energies for astrophysics. In order to improve the signal-to-noise ratio special care in experimental setups arrangement must be considered. In this talk I will review the experimental techniques adopted in underground nuclear astrophysics, giving an update of main results obtained, which shed lights on several key nuclear reactions that take place in various astrophysical scenarios. Moreover, I will give an overview of worldwide facilities, discussing the status and perspectives of the experiments which are running from several years or are in constructions or in early stage of development. I will, in particular, show their major scientific drivers, which will clearly lead to significant progress in answering many open questions in nuclear astrophysics

Speaker: Dr Alba Formicola (LNGS)

14 Catalysis of Nuclear Reactions by Electrons¶

Electron screening enhances nuclear reaction cross sections at low beam energies. This happens in many astrophysical scenarios, e.g. stellar burning or supernova explosions. Unfortunately, the process is still poorly understood. All currently used calculations are based on the very simple assumption that the electrons distributed evenly on a shell decrease the repulsive potential inside the shell by a constant. Although the measurements in principle obey the predicted functional behavior of electron screening, its magnitude is severely underestimated by the theory. I will overview the current experimental situation and propose an alternative understanding of the electron screening process with a possible proof of its validity.

Speaker: Dr Matej Lipoglavsek (Jozef Stefan Institute, Ljubljana, Slovenia)

15 Direct study of the 22Ne({\it p,γ})23Na reaction in inverse kinematics at DRAGON¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} \renewcommand{\thefootnote}{\fnsymbol{footnote}} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% The ${}^{22}$Ne({\it p,$\gamma$})${}^{23}$Na reaction largely impacts the abundance of the only stable sodium isotope, ${}^{23}$Na, in various stellar environments, such as AGB stars, massive enough to undergo hot-bottom burning, type Ia supernovae and novae. However, the ${}^{22}$Ne({\it p,$\gamma$})${}^{23}$Na reaction rate still carries one of the highest uncertainties among the astrophysical reactions involved in the NeNa cycle, thereby also affecting the abundance predictions of elements between ${}^{20}$Ne and ${}^{27}$Al. Reducing the uncertainties of abundance predictions for NeNa cycle elements by constraining the relevant reaction rates experimentally has received increased attention with the discovery of the anticorrelation between sodium and oxygen abundances in globular cluster stars. The thermonuclear reaction rate for the ${}^{22}$Ne({\it p,$\gamma$})${}^{23}$Na proton capture reaction is dominated by a number of narrow resonances within the Gamow window. Recently, a study with the objective to directly measure the strengths of the most relevant resonances in the ${}^{22}$Ne({\it p,$\gamma$})${}^{23}$Na reaction in inverse kinematics was carried out using the DRAGON (Detector of Recoils and Gammas Of Nuclear Reactions) recoil separator at TRIUMF. Resonances within an energy range from E${}_{c.m.}$=178~keV to E${}_{c.m.}$=1.222~keV were investigated. In this contribution the astrophysical motivation behind this measurement, as well as preliminary results of the first inverse kinematics study of the ${}^{22}$Ne({\it p,$\gamma$})${}^{23}$Na reaction will be presented. \bigskip {\small %%% End of abstract. %%% \end{document}

Speaker: Dr Annika Lennarz (TRIUMF)

Slides Lennarz.pdf

16 First results of total and partial cross-section measurements of the 107Ag(p, γ)108Cd reaction¶

The $\gamma$ process is assumed to play an important role in the nucleosynthesis of the majority of the p nuclei. Since the network of the $\gamma$ process includes so many different reactions and - mainly unstable - nuclei, cross-section values are predominantly calculated in the scope of the Hauser- Feshbach statistical model. The values heavily depend on the nuclear physics input-parameters. The results of total and partial cross-section measurements are used to improve the accuracy of the theoretical calculations. In order to extend the experimental database the 107Ag(p,$\gamma$)108Cd reaction was studied via the in-beam method at the high-efficiency HPGe $\gamma$-ray spectrometer HORUS at the University of Cologne. Proton beams with energies between 3.5 and 5.0 MeV were provided by the 10 MV FN-Tandem accelerator. First results on total and partial cross sections will be presented. Supported by the DFG (ZI 510/8-1) and the "ULDETIS" project within the UoC Excellence Initiative institutional strategy. P.S. and J.M. are supported by the Bonn-Cologne Graduate School of Physics and Astronomy.

Speaker: Mr Felix Heim (Institute for Nuclear Physics, University of Cologne)

17 Direct cross section measurement for the O-18(p,gamma)F-19 reaction at LUNA¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Francesca Romana Pantaleo (Universita' degli Studi di Bari, Dipartimento Interateneo di Fisica ''M. Merlin'', Bari, IT, INFN Bari,Bari, IT)

Slides Pantaleo.pdf

18 Absolute measurement of the 7Be(p,g)8B cross section with the recoil separator ERNA¶

7Be(p,g)8B still represents one of the major uncertainties on the predicted high energy component of solar neutrino flux and it has also a direct impact on the 7Li abundance after the Big Bang Nucleosynthesis. Previous experiments producing data with useful precision were performed in direct kinematics, using an intense proton beam on a radioactive 7Be target. The complicated target stoichiometry and the deterioration under beam bombardment might possibly be the origin of the discrepancies observed between the results of different measurements. Inverse kinematics, i.e. a 7Be ion beam and a hydrogen target, would shed light on systematic effects. Unfortunately, efforts attempted so far were limited by the low 7Be beam intensity. We present here a new experiment, exploiting a high intensity 7Be beam in combination with a windowless gas target and the recoil mass separator ERNA (European Recoil mass separator for Nuclear Astrophysics) at CIRCE (Center for Isotopic Research on Cultural and Environmental heritage), Caserta, Italy. Aim of the experiment is the measurement of the total reaction cross section by means of the direct detection of the 8B recoils. The experimental setup as well as results and their astrophysical impact will be illustrated.

Speaker: Raffaele Buompane (NA)

Slides Buompane.pdf

19 Production and characterization of 7Be targets for neutron cross section measurements¶

Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \begin{document} \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% This contribution presents the production and the characterization of ${}^7$Be targets used for the measurement of the ${}^7$Be(n,$\alpha$)${}^4$He and the ${}^7$Be(n, p)${}^7$Li cross sections in the energy range of interest for the Big-Bang nucleosynthesis.\\ In particular, two targets of 25 GBq and one of 4 GBq of ${}^7$Be were produced via molecular plating and via droplets deposition at PSI-Switzerland. These targets were used for the measurements of the ${}^7$Be(n, $\alpha$)${}^4$He cross section at n_TOF-CERN-Switzerland and at SARAF-Israel facilities. The thickness and the uniformity of the obtained targets were characterized by measuring the energy degradation of 5.5 MeV alpha particles passing through them. The obtained spectra were then simulated using the advanced alpha-spectroscopy simulation program (AASI) .\\ One target, used to measure the ${}^7$Be(n, p)${}^7$Li cross section at n_TOF-CERN facility, was obtained via implantation of about one GBq of chemically and isotopically pure ${}^7$Be ions into a thin aluminium disk. The implantation was carried out at the ISOLDE facility at CERN. After the measurement of the cross sections, the ${}^7$Be activity in the target and its spatial distribution were measured at PSI-Switzerland. \bigskip {\small %%% %%% End of abstract. %%% \end{document}

Speaker: Dr Emilio Andrea Maugeri (Paul Scherrer Institut)

Concert¶

Tuesday, 20 June ¶

n-induced nucleosynthesis¶

20 The Interaction of Neutrons With 7Be: Lack of Standard Nuclear Physics Solution to the “Primordial 7Li Problem”¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% The accurate measurement of the baryon density by WMAP renders Big Bang Nucleosynthesis (BBN) a parameter free theory with only inputs from measurements of the relevant (12 canonical) nuclear reactions. BBN predicts with high accuracy the measured abundance of deuterium, helion and helium relative to hydrogen, but it over-predicts the abundance of ${}^7$Li relative to hydrogen by a factor of approximately three and more than three sigma difference from the observed value. This discrepancy was observed early on (more than thirty years ago) and is known as the ``Primordial ${}^7$Li Problem". Several attempts to reconcile this discrepancy by destroying ${}^7$Be with deuterons and helions or a conjectured d + ${}^7$Be resonance were ruled out as solutions of the ${}^7$Li problem. But the interaction of ${}^7$Be with neutrons that are also prevailing during the epoch of BBN, was not directly measured thus far in the BBN window. Also a hitherto unknown n + ${}^7$Be narrow resonance in ${}^8$Be at energies relevant for the BBN window was not yet ruled out. A worldwide effort for measuring the interaction of neutrons with ${}^7$Be is currently underway [1] with ${}^7$Be targets prepared at the Paul Scherrer Institute (PSI) [2] and the ISOLDE at CERN. Measurements were performed by the n\_TOF collaboration [3], at the ILL in Grenoble [4], and in the new neutron facility at the Soreq Applied Research Accelerator Facility (SARAF) in Israel [5], as well as the time reversed measurement of ${}^4$He($\alpha$,n)${}^7$Be in Kyoto [6]. Only the SARAF measurement covers the ``BBN energy window" with T = 0.5 - 0.8 GK and kT = 43 - 72 keV. We will discuss the world wide effort to measure the interaction of neutrons with ${}^7$Be [3-6] with an emphasize on our measurement at the SARAF [5]. We measured a significantly small upper limit on the ${}^7$Be(n,$\alpha$) reaction and the first measurement of the ${}^7$Be(n,${\gamma }_1{)}^8$Be${}^{\ast }$(3.05 MeV) $\to \alpha +\alpha$ reaction (E${}_{\alpha }$ = 1.5 MeV). Our measurement allow us to re-evaluate the so designated ``${}^7$Be(n,$\alpha$) reaction rate" first derived by Wagoner in 1969 and still used in BBN calculations. Our evaluated new rate demonstrates that the last possible avenue (of the n + ${}^7$Be interaction) for a standard nuclear physics solution of the ${}^7$Li problem does not solve the problem. We conclude on lack of standard nuclear physics solution to the ``Primordial ${}^7$Li problem". \\ \ \\ ${}^{\ast }$ Work supported by the U.S.-Israel Bi National Science Foundation, Award Number 2012098, and the U.S. Department of Energy, Award Number DE-FG02-94ER40870. \bigskip {\small \noindent [1] Dorothea Schumann, Massimo Barbagallo, Thierry Stora, Ulli Koester and Moshe Gai, \\ \indent Nuclear Physics News, {\bf 26:4}, 20 (2016). \noindent [2] Emilio Andrea Maugeri {\em et al.}, in press, Journ. Instr. (2017). \noindent [3] Massimo Barbagallo {\em et al.}, and the n\_TOF collaboration, Phys. Rev. Lett. {\bf 117}, 125701 (2016). \noindent [4] Ulli Koester, private communication, 2016. \noindent [5] Emily Elizabeth Kading {\em et al.}, Bull. Amer. Phys. Soc. {\bf 61, \#13}, 28 (2016). \\ \indent Also E.E. Kading {\em et al.} contribution to this conference with a complete list of the collaboration. \noindent [6] Takahiro Kawabata {\em et al.}, Phys. Rev. Lett. {\bf 118}, 052701 (2017). %%% %%% End of abstract. %%% \end{document}

Speaker: Prof. Moshe Gai (University of Connecticut)

Slides Gai_NPA8.pdf

21 Studies of (n,gamma) and (n,cp) reactions for Nuclear Astrophysics at the n_TOF neutron beam (CERN)¶

Neutron-induced cross sections are a key nuclear physics input for the comprehension of stellar nucleosynthesis of heavy elements, as well as for modeling of light element production in Big Bang Nucleosynthesis. In stars, neutron capture reactions are responsible for the production of the majority of elements heavier than Fe, with two processes contributing more or less equally to the overall abundance pattern: the s- and r-process. The first one involves low neutron densities and stable or radioactive isotopes with relatively long half-life. In this context, accurate neutron capture cross sections are needed for heavy elements, as well as for a few light elements acting as neutron poisons, or involved in stellar neutron sources. In Big Bang nucleosynthesis, one of the most intriguing problems surviving since more than 40 years regards the large overestimate of the primordial abundance of Lithium by theoretical models. Neutron-induced reactions of relevance for Nuclear Astrophysics are being studied since many decades at neutron facilities worldwide. To address the still open issues in stellar and primordial nucleosynthesis, the n TOF Collaboration has been carrying out since several years an ambitious experimental program on nuclear capture reactions with the aim of reducing the uncertainty on cross sections relevant to s-process nucleosynthesis, and improve the reliability of astrophysical models. Several high quality results have been obtained thanks to the innovative features of the neutron beam of the n TOF facility at CERN, in particular the very high instantaneous neutron flux and the high resolution in the first experimental area at 200 m flight path, very convenient in particular for measurements of radioactive isotopes. More recently, the construction of a second experimental area at shorter flight path (20 m) opened the way to very challenging measurements of (n,γ) and (n,charged particle) reactions on isotopes of short half-life, or reactions with very low cross sections, or for isotopes available in a small amount. A first, successful example in this sense is the measurement of the 7Be(n,p) and (n,α) reactions of interest for the Cosmological Lithium problem. After a brief description of the facility and of the detection systems employed in the mea- surements, the program of the n TOF Collaboration in Nuclear Astrophysics will be presented in this talk, with particular emphasis on the recent results relevant for stellar nucleosynthesis, stellar neutron sources and primordial nucleosynthesis.

Speaker: Nicola Colonna (BA)

Slides Colonna.pptx

22 Informing Neutron Capture Nucleosynthesis on Short-Lived Nuclei with (d,p) Reactions¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Prof. Jolie Cizewski (Rutgers University)

23 Cosmological Lithium Problem: Measurement of the 7Be(n,α) and 7Be(n,p) cross sections at the n TOF facility at CERN¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Massimo Barbagallo (INFN sezione di Bari)

24 The thermal neutron capture of 171Tm¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Tanja Heftrich (Goethe University Frankfurt)

25 Measurements of the 7Be+n Big-Bang nucleosynthesis reactions at CRIB by the Trojan Horse method¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %-------- aliases --------% \newcommand{\benpli}{${}^7$Be$(n,p{)}^7$Li} \newcommand{\benaa}{${}^7$Be$(n,\alpha {)}^4$He} \newcommand{\bedlipp}{${}^7$Be$(d{,}^7$Li$p{)}^1$H} \newcommand{\bedaap}{${}^7$Be$(d,\alpha \alpha {)}^1$H} \newcommand{\bedpbe}{${}^7$Be$(d,p{)}^8$Be} \newcommand{\cm}{_{\rm c.m.}} \renewcommand{\refname}{} %-------- aliases --------% %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Seiya Hayakawa (Center for Nuclear Study, University of Tokyo)

Slides Hayakawa.pdf

10:50 Coffee break

RIBs in nuclear astrophysics 1¶

26 Beta decay spectroscopy studies of novae and x-ray bursts¶

Nucleosynthesis and energy generation in classical novae and type I x-ray bursts are driven by nuclear reactions. Many of the thermonuclear rates have substantial uncertainties that preclude accurate comparisons between astronomical observations and astrophysical models. A program of beta decay measurements utilizing intense sources of rare isotopes adjacent to the proton drip line has been established at the National Superconducting Cyclotron Laboratory. These measurements take advantage of high purity germanium arrays to detect beta delayed gamma rays that correspond to the exit channels of radiative capture reactions. Recently, a gas-filled detector of low-energy beta delayed charged particles has been constructed to measure the entrance channels. The information gained from these experiments can be used to determine the energies and strengths of resonances in several of the reactions that have the greatest influence on the modeling of astronomical observables.

Speaker: Chris Wrede (Michigan State University)

Slides Wrede.pptx

27 Measurement of key resonance states for the 30P(p,γ)31S reaction rate¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Anu Kankainen (University of Jyväskylä)

28 Constraining the 19Ne(p,γ)20Na Reaction Rate Using Direct Measurements at DRAGON¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Mr Ryan Wilkinson (University of Surrey)

Slides Wilkinson.pdf

29 Understanding the origin of ``nova'' grains and the 13N(α,p)16O reaction¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Nicolas de Séréville (IPN Orsay)

30 Commissioning of the BRIKEN beta-delayed neutron detector for the study of exotic neutron-rich nuclei¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Alvaro Tolosa Delgado (IFIC (Instituto de Fisica Corpuscular))

31 Isomer beam elastic scattering: 26mAl(p,p) for astrophysics¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in \renewcommand{\refname}{} %-------- aliases --------% %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Daid Kahl (University of Edinburgh)

Slides Kahl.pdf

13:30 Lunch

Direct measurements 2¶

32 Cross section measurements in the 12C+12C system¶

Fusion reactions play an essential role in understanding the energy production, the nucleosyn- thesis of chemical elements and the evolution of massive stars. Thus, the direct measurement of key fusion reactions at thermonuclear energies is of very high interest. The carbon burning in stars is essentially driven by the 12C+12C fusion reaction. This reaction is known to show prominent resonances at energies ranging from a few MeV/nucleon down to the sub-Coulomb regime, possibly due to molecular 12C-12C configurations in 24Mg [1]. The persistnce of such resonances down to the Gamow energy is still an open question. This reaction could also be subject to the fusion hindrance phenomenon which has been evidenced for medium mass systems [2]. This contribution will discuss recent measurements performed in this system at deep subbarrier energies using the γ-particle coincidence technique. [1] D. Jenkins and S. Courtin J. Phys. G: Nucl. Part. Phys. 42 034010 (2015); [2] C.L. Jiang et al., Phys.Rev. Lett.89 052701(2002).

Speaker: Prof. Sandrine Courtin (IPHC STrasbourg)

33 Background (α,n) reactions at low energies: 10,11B(α,n)13,14N¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% New underground facilities like CASPAR and LUNA-MV, which are set to begin operation in the next few years, will push $\alpha$-induced reaction measurements to record low energies. Of particular interest are the neutron-producing reactions ${}^{13}$C$(\alpha ,n{)}^{16}$O and ${}^{22}$Ne$(\alpha ,n{)}^{25}$Mg, which fuel the $s$ process. At low energies these cross sections are dominated by their Coulomb penetrabilities. In addition, the relative difference in Coulomb penetrabilities for $\alpha$-induced reactions on targets with different charge $Z$, is much larger than for their proton-induced counter parts. Yet already small amounts of contaminant material, of lower $Z$ than the target material of interest, have been observed to induce large background yields in proton-induced capture reactions. Therefore, the study of low $Z$ background reactions is critical for both the planning and interpretation of future low energy measurements of the ${}^{13}$C$(\alpha ,n{)}^{16}$O and ${}^{22}$Ne$(\alpha ,n{)}^{25}$Mg reactions. This is especially true if a counter type detector will be used, e.g. ${}^3$He, that is insensitive to neutron energy. As boron is a common trace material in solid targets, and has already been observed as a contaminant in $(p,\gamma )$ measurements (e.g. [1]), this paper reports on a new study of the ${}^{10,11}$B$(\alpha ,n{)}^{13,14}$N reactions. Measurements have been performed at the University of Notre Dame's Nuclear Science Laboratory using the Santa Anna 5~MV accelerator. Both a traditional ${}^3$He counter and a new type of deuterated scintillation detector [2], which is sensitive to the neutron energy, have been utilized. This research was supported by the National Science Foundation through Grant No. Phys-0758100, the Joint Institute for Nuclear Astrophysics through Grant No. Phys-0822648 and PHY-1430152 (JINA Center for the Evolution of the Elements), and the Department of Energy Office of Science. \bigskip {\small \noindent [1] A.~Di~Leva \textit{et al.}, Phys. Rev. C {\bf 89} 015803 (2014); \noindent [2] F.D.~Becchetti \textit{et al.}, Nucl. Instrum. Methods A{\bf 820} 112 (2016). %%% %%% End of abstract. %%% \end{document}

Speaker: Dr Richard deBoer (University of Notre Dame)

Slides deBoer.pdf

34 An above-ground low-energy measurement of the dominant s-process neutron source: 13C(α,n)16O¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Michael Febbraro (Oak Ridge National Laboratory)

35 Felsenkeller 5 MV underground accelerator¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Daniel Bemmerer (Helmholtz-Zentrum Dresden-Rossendorf)

Slides Bemmerer.pdf

36 Astrophysical Impact of Recent Measurements of the 23Na(α,p)26Mg Reaction¶

The 23 Na(α,p) 26 Mg reaction has been identified as having a significant impact on the nucleo- synthesis of elements, such as 23 Na [1] and 26 Al [2], in massive stars, and of light isotopes in type-Ia supernovae [3]. We will present new experimental results, as well as a combined reaction rate based on all available data, and an assessment of its astrophysical impact on massive stars and type-Ia supernovae. Until 2014 this reaction was only measured in experiments which suffered from normalisation issues. Accordingly, reaction rate compilations such as REACLIB preferred Hauser-Feshbach statistical reaction rates, whose uncertainty may be greater than a factor of 3 for alpha-induced reactions. These uncertainties may be further compounded by the relatively light nuclei involved, where the level density is low. An improved experimental measurement was therefore suggested in reference [2]. Since 2014 there have been several measurements of the reaction utilising various new techniques to avoid the earlier experimental issues [4 – 8]. All of the experiments have found results consistent with one another, as well as with Hauser-Feshbach predictions in the energy range E cm = 1.7 − 3.0 MeV. We have directly measured new angular distributions using the setup in reference [5] and have corrected the data in references [4, 6] based on these angular distributions, in order to reduce their systematic uncertainty. From these corrected data we calculate a new, combined, experimental reaction rate. We have then implemented this reaction rate into astrophysical models of massive stars and type-Ia supernovae to identify its impact on the nucleosynthesis of key isotopes, and from these provide improved constraints on abundances. These constraints may help to identify the primary astrophysical site of 26 Al production. The impact of this new experimental rate on hydrostatic shell burning in massive stars, explosive burning in massive stars, and type-Ia supernovae was determined using the nuclear post-processing codes ppn [9] and a delayed detonation model reference [10]. The change in abundance of isotopes in the region of A = 20 − 30 was calculated and compared to REACLIB reaction rates, along with the uncertainty in isotopic abundances. The impact of these results on galactic 23 Na and 26 Al production will be discussed.

Speaker: Mr Nicolas Hubbard (University of York and Aarhus University)

37 Nuclear astrophysics projects at the low-energy RI beam separator CRIB¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %-------- aliases --------% \newcommand{\benpli}{${}^7$Be$(n,p{)}^7$Li} \newcommand{\benaa}{${}^7$Be$(n,\alpha {)}^4$He} \newcommand{\bedlipp}{${}^7$Be$(d{,}^7$Li$p{)}^1$H} \newcommand{\bedaap}{${}^7$Be$(d,\alpha \alpha {)}^1$H} \newcommand{\bedpbe}{${}^7$Be$(d,p{)}^8$Be} \newcommand{\cm}{_{\rm c.m.}} \renewcommand{\refname}{} %-------- aliases --------% %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Hidetoshi Yamaguchi (Center for Nuclear Study, the University of Tokyo)

16:50 Coffee break

r-process 3¶

38 Nuclear masses and the r-process astrophysical site¶

The key role played by nuclear masses in rapid neutron capture, or r-process, nucleosynthesis has long been recognized. Masses set the reaction flow path for an r-process in equilibrium and influence the neutron capture rates, beta decay rates, and fission properties that determine the final abundances. Here we describe modern efforts to quantify the uncertainties in r-process abundance patterns that result from uncertainties in nuclear masses. In addition we describe a new method to gain insight into the r-process astrophysical environment via the reverse-engineering of unknown nuclear properties. As a specific example, we discuss the rare earth region and show how different assumptions of astrophysical conditions result in distinct predictions for the mass surface in this region. The mass trends we identify will be directly testable by experiment in the near future.

Speaker: Prof. Rebecca Surman (University of Notre Dame)

39 Beta-delayed neutron emission probability measurements for r process studies at RIKEN RIBF¶

About 50% of the isotopes heavier than iron are synthesized in the so-called astrophysical r-process [1]. During the explosion of a type II supernovae or a Neutron star merger exotic isotopes, closed to the drip line are formed via rapid neutron capture reactions [2]. These, very neutron-rich nuclei emit neutrons after the beta-decay when the decay Q-value is larger than the neutron separation energy of the daughter nucleus. These beta-delayed neutrons play an important role during freeze-out in redistributing the initial isotopic distribution of matter and thus smoothing the final abundance pattern as observed in the solar system [3]. Recent studies have also highlighted that freeze-out is not instantaneous and neutron capture during this phase is responsible for some of the main features of the r-process abundance pattern such as the rare earth peak (REP) at A~160 [4] (and references therein). Last year the BRIKEN neutron detector has been built at the BigRIPS separator at RIKEN Nishina Center (Wako-shi, Japan) to study the decay properties of the most neutron-rich nuclei produced through the fragmentation of high intensity 238U primary beam. The BRIKEN detector consists of the world largest array of 3He counters [5], the most advanced implantation array, AIDA [6] and clover-type HPGe detectors and, therefore, it's suitable to measure the half-life and the beta-delayed neutron emission probability of the isotopes located on the r-process path. The aim of this presentation is to introduce the scientific program of the collaboration and show the results of the first measurement carried out in the Al-Mg region in 2016. Furthermore, the experimental details of the first campaign performed in Spring 2017 will be presented, too. [1] F.-K. Thielemann et al., Prog. Part. Nucl. Phys. 66 346 (2011); [2] S. Wanajo, Astrophys. Jour. Lett. 789 L39 (2014); [3] R. M. Mumpower et al., Prog. Part. Nucl. Phys. 86 86 (2016); [4] R. M. Mumpower et al., Physical Review C 85 45801 (2012); [5] A. Tarifeno-Saldivia et al., https://arxiv.org/abs/1606.05544, IOP Jour.of Instr. (2016); [6] C. Griffin et al., Proceedings of Science (NIC XIII) 097 (2014);

Speaker: Gabor Kiss (RIKEN Nishina Center)

Slides Kiss.pdf

40 Neutron capture rates for the astrophysical r process¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Artemis Spyrou (NSCL/MSU)

Slides Spyrou.pdf

41 Equation of State and in-medium nuclear structure in heavy-ion collisions¶

Heavy-ion collisions provide unique access to nuclear structure properties away from saturation density and at finite temperatures. Such structure properties are determined by the equation of state (EoS) and the symmetry energy of nuclear matter that can in turn be studied under laboratory controlled conditions. Such conditions are encountered in neutron stars and in core collapse supernovae explosions. Alpha clustering phenomena in nuclear matter under such extreme conditions [1] are indeed relevant to the neutrinosphere of core collapse supernovae where the opacity of dilute and hot nuclear matter to outgoing neutrinos determines the explosion dynamics and the nucleosynthesis of medium heavy elements. By means of single particle observables and multi-particle correlation measurements [2] with 4$\pi$ detectors and high resolution correlators one can measure nuclear structure properties, such as spin and branching ratios of unbound states in stable and exotic nuclei, while controlling the temperature and density of the nuclear medium where such nuclei are produced. Experimental results from such measurements performed with the INDRA and LASSA detectors at different beam energy regimes will be presented [3-5]. Among them we mention the possibility to determine properties of astrophysically important states in ${}^8$B, decaying into proton+${}^7$Be [3], as well as probes of the decay branching ratios of the Hoyle state in ${}^{12}$C, decaying into three alphas either via a direct or a sequential mechanism [4]. Such decays occur in a nuclear medium whose density and temperature are extracted via intensity interferometry techniques (similar to those used in astronomy to determine the size of stars) and the measurement of relative population of states in unbound nuclei [2]. The perspectives offered by the coming up FAZIA [6] campaigns at GANIL, in coupling to the INDRA 4$\pi$ array, aimed at studying the density dependence of the symmetry energy in the nuclear EoS, including its interplays with in-medium nuclear structure and clustering , will be presented and discussed. [1] S. Typel et al., Phys. Rev. C 81, 015803 (2010); [2] G. Verde et al., Eur. Phys. J. A 30, 81 (2006); [3] W. Tan et al., C 69, 061304(R) (2004); [4] F. Grenier et al., A 811, 233 (2008); [5] P. Marini et al., Phys. Lett. B 756, 194 (2016); [6] R. Bougault et al., Eur. Phys. J. A 50, 47 (2014); F. Salomon et al., J. of Instrum. 11, C01064 (2015);

Speaker: Giuseppe Verde (CT)

42 Constraining The Symmetry Energy (Far) Above Saturation Density Using Elliptic Flow¶

Using a quantum molecular dynamics type transport model coupled to a phase-space coalescence algorithm to determine final spectra of intermediate energy heavy-ion collisions it has been shown that the elliptic flow ratios of neutrons-to-protons and neutrons-to-hydrogen probe, on average, different density regimes of the compressed nuclear matter created in such reactions [1]. This fact is used to study the density dependence of the symmetry energy around twice saturation density by extracting constraints for the slope L and curvature Ksym parameters at saturation using the mentioned observables [2]. To that end, the Gogny type parametrization of the nuclear matter equation of state [3] is extended by the introduction of an extra term that allows independent adjustments of the values of the L and Ksym parameters and without affecting the value of the isovector nucleon mass splitting. The momentum dependent part is modified to agree with the empirical energy dependence of the nucleon optical potential. Constraints of the value of the symmetry energy at particular sub-saturation density values, extracted from nuclear structure experimental data, are accounted for [4]. Values for the slope and curvature parameters are determined from a comparison with experimental data for elliptic flow ratios in 197Au+197Au collisions at an impact energy of 400 MeV/nucleon due to the FOPI-LAND [5,6] and ASYEOS [1] Collaborations: L=50±20 MeV and Ksym=150±300 MeV. The magnitude of the residual model dependence due to elastic cross-sections parametrizations, value of the isovector mass splitting and scenario chosen for the conservation of the total energy of the system [7,8] is investigated. The results are compatible with a stiffer density dependence of the symmetry energy than the one advanced by studies that limit themselves to the extraction of constraints only for the slope parameter L and may offer a simple resolution of the hyperon puzzle. The sizable uncertainties that plague the extrapolation of our result in the 3-4rho0 density region will need to be substantially reduced before a final conclusion on this problem can be drawn. Experimental measurements of elliptic flow observables that are in the planning phase at GSI (Darmstadt) will provide such an opportunity in the near future. [1] P. Russotto et al., Phys. Rev. C94 034608 (2016); [2] M.D. Cozma, in preparation; [3] C. Das, S.D. Gupta, B.A. Li, Phys. Rev. C 67 034611 (2003); [4] B.A. Brown, Phys.Rev.Lett. 111 232502 (2013); [5] P. Russotto et al., Phys. Lett. B 697 471 (2011); [6] M.D. Cozma et al., Phys. Rev. C 88 44912 (2013); [7] M.D. Cozma, Phys. Lett. B 753 166 (2016); [8] M.D. Cozma, Phys. Rev. C 95 014601 (2017);

Speaker: Dr Dan Cozma (IFIN-HH)

Poster session¶

43 7Li(a,g)11B : An update¶

At the end of its life, a massive star collapses into a neutron star. The neutrino flux released during the collapse is so significant that the probability of a neutrino interacting with a nucleus is enhanced enough to have an influence on element nucleosynthesis [1]. The origins of light elements, specifically ${}^{11}B$, is not fully understood. The $\nu$-process has been proposed as a candidate for ${}^{11}B$ production [2]. Neutrino triggered reactions lead to the creation of ${}^{11}B$, with the reaction ${}^{7}Li(\alpha ,\gamma {)}^{11}B$ as a component of the main reaction chain. This reaction was recently studied at Notre Dame and the results of that measurement will be presented.

Speaker: Ms Gwenaelle Gilardy (University of Notre Dame)

44 A new measurement of the 6Li(p,gamma)7Be cross section at LUNA¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% The detection of ${}^6$Li in stars is a powerful tool for understanding the Big Bang nucleosynthesis, as well as the early stellar structure and evolution.\\ In stars, lithium is quickly destroyed during the pre-main sequence and main sequence phases, at temperatures of about 2 MK. Theoretical predictions of lithium abundances in the stellar surface are strongly dependent on the input physics and in many cases non-standard processes are required to explain the observed abundances [1].\\ The ${}^6$Li depletion proceeds mainly through the ${}^6$Li(p,$\alpha$)${}^3$He reaction. This reaction has been studied by many groups, and in order to explain the angular distribution of the emitted alpha particles, an R-matrix fit of the experimental data requires the contribution of both negative and positive parity excited states [2]. \\ Although the existence of positive parity excited states in ${}^7$Be has never been confirmed experimentally, a recent measurement of the ${}^6$Li(p,$\gamma$)${}^7$Be cross section revealed a possible resonance-like structure at center of mass energy of 195 keV [3]. The observed S-factor is reproduced by an R-matrix fit assuming the existence of an excited state with E $\approx$ 5800 keV and J${}^{\pi }$ = (1/2${}^{+}$, 3/2${}^{+}$).\\ A new measurement of the ${}^6$Li(p,$\gamma$)${}^7$Be cross section at proton energies between 50 and 400 keV has been performed at the Laboratory for Underground Nuclear Astrophysics. The poster provides a description of the experimental setup and preliminary results of the data analysis. \bigskip {\small \noindent [1] E. Tognelli et al. A\&A \textbf{548}, A41 (2012)\\ \noindent [2] J. Cruz et al. J. Phys. G Nucl. Part. Phys. \textbf{35}, 014004 (2008)\\ \noindent [3] J. J. He et al. Phys. Lett. B \textbf{725}, 287-291 (2013)\\ %%% %%% End of abstract. %%% \end{document}

Speaker: Rosanna Depalo (P)

45 Alpha induced reaction cross section measurements on 197Au¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Tamás Szücs (MTA Atomki)

46 Asymptotic normalization coefficients of 12B and 12N and halo radii of their excited states¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in

Speaker: Prof. Tatyana Belyaeva (Universidad Autonoma del Estado de Mexico)

47 Breakup of 8B on 58Ni at energies below the Coulomb barrier and the astrophysical S17(0) factor revisited¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % \documentclass[11pt]{article} \usepackage{graphicx} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in \hyphenation{cons-truction} \hyphenation{di-fferent} \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ Calculations of breakup and direct proton transfer by Continuum-Discretized Coupled Channels (CDCC) were made for the ${}^{8}B$+${}^{58}Ni$ system at energies around the Coulomb barrier $E_{B_{c.m.}}=20.8MeV$. For the ${}^{7}Be$-target interaction, we used a Semimicroscopic Optical Model that combines microscopic calculations of the mean-field double folding potential and a phenomenological construction of the dynamical polarization potential (DPP) [1]. The DPP parameters were fitting to reproduce the elastic scattering angular distributions of ${}^{8}B$ on ${}^{58}Ni$ at various energies [2] (Fig. 1), the ${}^{8}B$ breakup angular distributions at $25.75MeV$ [3], and the energy dependence of the fusion cross sections for the ${}^{8}B$+${}^{58}Ni$ system [2]. We also study the effect of different proton-core and -target interactions on the breakup angular distributions in comparison with the previous calculations [4]. Preliminary value of the spectroscopy factor for ${}^{8}B$ $\to$ ${}^{7}Be+p$ vertices $S_{exp}=1.0$ was deduced from comparison with the data [5]. It allowed us to estimate the asymptotic normalization coefficient, $C^2=0.49f{m}^{-1}$, and the astrophysical $S_{17}(0)$ factor to be $18.8eVb$, which are in good accordance with the published results [5]. \vspace{-2mm} $$\text{Unknown environment 'figure'}$$ \textit{Work partially supported by CONACYT, Mexico.} \bigskip {\small \noindent [1] S. A. Goncharov and A. Izadpanah, Phys. At. Nucl. \textbf{70} (2007) pp. 18-28. \noindent [2] E. F. Aguilera \textit{et al}., Phys. Rev. C \textbf{79}, 021601(R) (2009). \noindent [3] J. J. Kolata \textit{et al}., Phys. Rev. C \textbf{63}, 024616 (2001). \noindent [4] T. L. Belyaeva \textit{et at}., Phys. Rev. C \textbf{80}, 064617 (2009) \noindent [5] O. R. Tojiboev \textit{et al}., Phys. Rev. C. \textbf{94}, 054616 (2016). \end{document}

Speakers: Mr Juan Carlos Morales-Rivera (Universidad Autónoma del Estado de México), Prof. Tatyana Belyaeva (Universidad Autonoma del Estado de Mexico)

48 Can the electron capture on 7Be provide a nuclear solution to the solar Li problem?¶

The nucleosynthesis of 7Li represents one of the most crucial problems in nuclear astrophysics. The 7Li abundances of several atrophysical sites are hard to be reproduced: in particular, the 7Li abundance observed in the solar photosphere appears to be about 100 times lower than in meteorites. Recently, a new model for non-convective mixing mechanism induced by magnetohydrodynamics (MHD) was developed [1] and applied to explain the 13C-pocket formation in the He-rich regions during AGB phases [2] as well as the isotopic composition of presolar oxide grains of AGB origin [3]. This new formalism can be applied only in the case where the density of the stellar layers of interest decreses rather quickly with the radius, indeed this fact ensures a quasi-ideal MHD. We found that in the Sun this condition doesn't hold and it implies that magnetic buoyancy effects (which exist, as certified by the solar activity) require a much more complex numerical formulation and have to be less effective in the abundance reorganization than found in AGB stars. The solution of the Li problem must therefore be looked for elsewhere. Thanks to a new theoretical estimate of stellar e- capture on 7Be, and therefore of 7Li production, that has been performed in the past few years [4], we computed the lithium abundance for the Sun. Apart from possible mixing processes of different physical nature, our preliminary results indicate that a larger depletion of Li can indeed be obtained. This is a promising result, which indicates that a nuclear solution to the solar Li problem may in principle exist. In order to explore this in more detail, we are now improving the model for the mentioned rate, by introducing a fully relativistic, quantum mechanics extension. [1] M.C. Nucci and M. Busso, The Astrophysical Journal, 787, 141 (2014); [2] O. Trippella et al., The Astrophysical Journal, 818, 125 (2016); [3] S. Palmerini et al., submitted to Monthly Notices of the Royal Astronomical Society (2017); [4] S. Simonucci et al., The Astrophysical Journal, 764, 118 (2013).

Speaker: Diego Vescovi (PG)

49 Characterization of a Large Batch of X3 Silicon Detectors for the ELISSA Array at ELI-NP¶

S. Chesnevskaya1, C.Matei1, D.L. Balabanski1, D.M. Filipescu1, D.G. Ghita1, A. Rotaru1, A. State1, Y. Xu1 G.L. Guardo2, M. La Cognata2, D. Lattuada2, C. Spitaleri2 1. ELI-NP/ IFIN-HH, 30 Reactorului Street, 077125 Magurele, Romania 2. INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, 95123 Catania, Italy Position-sensitive silicon strip detectors represent one of the best solutions for the detection of charged particles as they provide good energy and position resolution over a large range of energies. A silicon array coupled with the gamma beams at the ELI-NP facility would make it possible to measure photodissociation reactions of interest for Big Bang Nucleosynthesis and on heavy nuclei intervening in the p-process. Particular attention will be focused on the problem of 7Li primordial abundance, which remains an open question in nuclear astrophysics for more than 20 years. Several recent theoretical calculations could not reproduce the 3H(4He,γ)7Li cross section while agreeing to measured 3He(4He,γ)7Be parameters. Forty X3 detectors for our ELISSA project have been recently purchased and tested. We investigated several specifications, such as leakage currents, depletion voltage, and detector stability under vacuum. The energy and position resolution, and ballistic deficit were measured and analyzed. This paper presents the main results of our extensive testing. The measured energy resolution for the X3 detectors is better than results published for similar arrays (ANASEN or ORRUBA). For the first time, remote-controlled motors were used to move the alpha source along the detector enabling automated detector scanning. Details of future characterization of the X3 detectors with charged particle beams and a preparatory 7Li(γ,3H)4He experiment at High Intensity Gamma-Ray Source (HIGS) will be presented.

Speaker: Dr Svetlana Chesnevskaya (IFIN-HH (ELI-NP))

50 Commissioning of EMMA¶

The electromagnetic mass analyser (EMMA) is a new vacuum-mode recoil mass spectrometer located at the ISAC-II facility at TRIUMF, Vancouver, Canada. Assembly of the spectrometer was completed in 2016, and it received first beam in December 2016. The first in-beam test consisted of an 80 MeV 36Ar beam impinged on a 4.46 μm 197Au foil. The initial test proved to be very successful, with the spectrometer able to identify and scan across several charge states for both the scattered beam and back-scattered target nuclei. The dispersion of these charge states agrees very well with ion optical calculations used to design the spectrometer, and the m/q resolution is comparable to what would be expected given the large energy spread of ions emerging from the target. During the coming year EMMA will be extensively tested with an alpha source, followed by a second in-beam commissioning exercise scheduled for September. This poster will introduce the design capabilities of the spectrometer and discuss results obtained from the first in-beam test and alpha source commissioning, along with further discussion on applying EMMA to study reaction rates of astrophysical interest.

Speaker: Mr Matthew Williams (University of York / TRIUMF)

51 Critical interaction and strong-absorption distances for the 7Li + 58Ni system¶

\thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% It is well known that in order to understand the composition of stars and how they produce energy, it is essential to know about nuclei as well as the reactions that they undergo. Lithium-7 as well as lithium-6 had a very low production after the Big Bang which might wrongly give the impression that the study of these nuclei are not as important as other nuclei. With this in mind, new experimental data on nuclear reactions are always welcome. Just recently, the Heavy-Ion Group made measurements of ${}^7$Li elastically scattered from ${}^{58}$Ni at energies around the Coulomb barrier. The measurements were made at the Tandem Van de Graaff particle accelerator in the National Institute for Nuclear Research (ININ) in Mexico. In this work critical interaction and strong-absorption distances were determined from these elastic data. We also present an analysis by using different potentials in order to describe the data just mentioned. %\bigskip %{\small %\noindent [1] E. Stark, Phys. Journal of the North 83 045801 (2011); %\noindent %[2] O. Martell et al. submitted to Solar Physics Letters (2013).} %%% %%% End of abstract. %%% \end{document}

Speaker: Dr Tatyana Belyaeva (Universidad Autónoma del Estado de México)

52 Determining the 13C(α,n)16O absolute cross section trough the concurrent application of ANC and THM and astrophysical consequences for the s-process in AGB-LMSs.¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Oscar Trippella (PG)

53 Direct measurement of the 13C(α,n)16O reaction at LUNA¶

Heaviest nuclei (A > 58) are synthesized by sequential neutron capture reactions. There are two main processes, depending on their time scale compared with the beta decay lifetime: these are the so called slow (s) and rapid (r) processes. Both produce about half of the stable isotopes beyond iron in the Universe [1]. Focusing on the s process, these take place in low mass (1 − 3M⊙) Asymptotic Giant Branch (AGB) stars, and their main neutron source is the identified in the 13C(α,n)16O reaction. The temperatures involved in these processes are in the range between 90 - 100 MK, which roughly correspond to Gamow energies between 180 and 200 keV. At present, the cross section within the Gamow peak is uncertain by almost one order of magnitude, having a large impact on stellar models. Currently, direct measurements of the reaction are done at energy above the Gamow window [2, 3]. Extrapolations or indirect measurements have been used to extend the cross section up to lower energies [4], but these need a renormalization or theoretical inputs. The low background condition in the LNGS deep underground laboratory, combined with the LUNA accelerator [5, 6] offers a unique possibility to perform this measurement with a direct technique at lower energies. In this talk, I will present the current state of the project, including neutron detectors perfor- mance and enriched 13C solid target characterization.

Speaker: Giovanni Francesco Ciani (GSSI)

54 Explosive kilonovae and nucleosynthesis in exotic quark models¶

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Speaker: Prof. J.E. Horvath (IAG-USP, Sao Paulo, Brazil)

55 High-precision mass measurements for the rp-process at JYFLTRAP¶

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Speaker: Ms Laetitia Canete (University of Jyväskylä)

56 Introduction of the new LUNA experimental setup for high precision measurement of 13C(α,n)16O reaction for astrophysical purposes¶

Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy Introduction of the new LUNA experimental setup for high precision measurement of 13C(α,n)16O reaction for astrophysical purposes L. Csedreki1, G. F. Ciani2, I. Kochanek1 for the LUNA collaboration 1 INFN, Laboratori Nazionali del Gran Sasso LNGS, Assergi, Italy 2 Gran Sasso Science Institute, L’Aquila Contact email: csedreki.laszlo@lngs.infn.it The 13C(α,n)16O reaction is very important in astrophysical context. This reaction is the dominant neutron source for the synthesis of the main s-process component of heavy elements in thermally pulsing, low-mass asymptotic giant branch stars. As a new project at the LUNA 400 kV accelerator, the investigation of this reaction is being performed in the Laboratori Nazionali del Gran Sasso (LNGS), Italy. This underground laboratory provides an ideal environment to detect rare events from astrophysical reactions thanks to the strong reduction in cosmic-ray induced background. For the above mentioned purpose the experimental setup needs to be able to detect the reaction neutrons with high efficiency, also considering possible angular distributions. Multistage target holder, high capacity cooling system and the implementation of the in-beam checking of target thickness is also required. Moreover, due to the low cross section of the 13C(α,n)16O reaction in the planned alpha energy range, the minimization of environmental and beam induced background are essential. The poster introduces the design and the parameters of the experimental setup including the process of target composition analysis using various techniques.

Speaker: Mr Laszlo Csedreki (INFN LNGS)

57 Measurements of the 10B(p,α0) 7Be cross section at astrophysical energies using the Trojan Horse Method¶

For nucleosynthesis calculations precise reaction rates should be known at energies close to the Gamow peak. Accurate measurements of nuclear reactions performed at these energies [1-5] shows an unexpected enhancement of the cross section at the lowest measurable energies that is attributed to the presence of atomic electrons in the target. In order to observe the bare nuclear cross section, it is possible to perform experiments where the cross section is measured indirectly, as for example with the Trojan Horse Method (THM). In this method the electron screening effect is neglected since the measurements take place at much higher energies [6]. The THM has been applied to the quasifree 2H(10B,α_0,7Be)n reaction induced at a boron-beam energy of 28 MeV. The astrophysical S-factor of the 10B(p,α_0)7Be reaction was measured in a wide energy range, from 5 keV to 2.5 MeV. In this experiment has been achieved a much better energy resolution as compared to the previous one [7] allowing the significantly better separation of the 8.654 MeV and 8.699 MeV 11C levels. Since the 8.699 MeV resonance lies at the Gamow peak energy for the 10B(p,α)7Be reaction, the proper subtraction of events belonging to the subthreshold level at the 8.654 MeV is necessary for accurate determination of the astrophysical S-factor and so, electron screening potential. [1] C. Rolfs, W.Rodney, Cauldrons in the Cosmos, The University of Chicago, 561 (1988); [2] H. Assenbaum et al., Z. Phys. A 327, 461 (1987); [3] G. Fiorentini et al., Z. Phys. A 350, 289 (1995); [4] F. Strieder et al., Naturwissenschaften 88, 461 (2001); [5]E. G. Adelberger et al., Rev. Mod. Phys. 195, 83 (2011); [6] S. Typel, H. H. Wolter, Few-Body Systems 29, 75 (2000); [7] C.Spitaleri et al., Phys. Rev. C 90, 035801 (2014).

Speaker: Mrs Aleksandra Cvetinović (INFN-LNS Catania)

58 Nanostructured surfaces for nuclear astrophysics studies by laser-matter interactions¶

The future availability of high-intensity laser facilities capable of delivering tens of Petawatts of power (e.g. ELI-NP) into small volumes of matter at high repetition rates will give the unique opportunity to investigate nuclear reactions and fundamental interactions under the extreme plasma conditions realized by laser-matter interactions. Nuclear reactions of astrophysical interest are typically investigated by using ion beams that collide on fixed targets. However, the universe is composed of matter mainly in the form of plasma, where reaction mechanisms could change dramatically. For this reason, the investigation on reaction rates in plasma could provide important knowledge in astrophysics and cosmology. In this context, targets made of nanostructured materials are giving promising indications to reproduce plasma conditions suitable for measurements of thermonuclear fusion reaction rates, in the domain of nanosecond laser pulses. The present work gives the results of measurements performed with several kinds of nanostructured targets irradiated by laser pulses 6 ns long and at the energy of 2 Joules. The Nd:YAG laser installed at LENS laboratory of INFN-LNS in Catania has been used. The nanostructured targets consist of aligned metal nanowires grown by electrodeposition into a porous alumina matrix, obtained on a thick aluminum substrate. These metamaterials were developed with specific geometrical parameters in order to maximize absorption in the visible and IR range. A strong enhancement of the plasma-produced X-ray flux has been observed, with some clear signatures about a “stagnation” of the plasma plume which is a critical condition for the self-thermalization of the system. In perspective, this kind of alumina matrices could be filled with the atomic species needed to investigate specific nuclear reactions, in laser-produced plasmas.

Speaker: Carmen Altana (LNS)

59 Neutron capture cross sections of Kr¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Mr Stefan Fiebiger (Goethe University Frankfurt)

60 Search for Deeply Bound Kaonic Nuclear States in AMADEUS experiment¶

Search for Deeply Bound Kaonic Nuclear States in AMADEUS experiment M. Skurzok1,2, C. Curceanu2, L. Fabbietti3,4, R. del Grande2,5, P. Moskal1, K. Piscicchia2,6, A. Scordo2, D. L. Sirghi2, Oton Vazquez Doce3,4 1 Institute of Physics, Jagiellonian University, 30-059 Krakow, Poland 2 INFN, Laboratori Nazionali di Frascati, 00044 Frascati, Italy 3 Excellence Cluster Origin and Structure of the Universe, 85748 Garching, Germany 4 Physik Department E12, Technische Universitat Munchen, 85748 Garching, Germany 5 Università degli Studi di Roma Tor Vergata, Rome, Italy 6 Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Roma, Italy Contact email: magdalena.skurzok@uj.edu.pl Deeply Bound Kaonic Nuclear States are currently one of the hottest topics in nuclear and hadronic strangeness physics, both from experimental and theoretical points of view. The existence of bound kaonic nuclear states of K−, also called kaonic nuclear clusters, was firstly predicted in 1986 [1]. The phenomenological investigations, resulted in deeply bound nuclear states with narrow widths and large binding energies which can reach 100 MeV in kaon-nucleon-nucleon system (K−pp), being a consequence of the strongly attractive K− - proton interaction. Recent theoretical studies, based on different methods are giving a wide range of possible values for the binding energies of the kaonic nuclear states, ranging from few MeV up to about 100 MeV [2-5]. Therefore, in order to clarify this issue, experimental data are needed. The research would be very important in understanding the fundamental laws of the Nature and Universe. It can have important consequences in various sectors of physics, like nuclear and particle physics as well as astrophysics. The binding of the kaon in nuclear medium may impact on models describing the structure of neutron stars (Equation of State of neutron stars) [6,7] including binaries which are expected to be sources of the gravitational waves. Investigation of stable forms of strange matter like DBKNS in extreme conditions would be helpful for a better understanding of elementary kaon - nucleon interaction for low energies in the non-perturbative quantum chromodynamics (QCD) and in consequence, would contribute to solve one of the crucial problems in hadron physics: hadron masses (related to the chiral symmetry breaking), hadron interactions in nuclear medium and the structure of the dense nuclear matter. The AMADEUS group has developed a method having a high chance for discovery of DBKNS corresponding to K−pp, K−ppn and K−ppnn kaonic nuclear clusters and their decay to Λp, Λd and Λt, respectively. The method is based on the exclusive measurement of the momentum, angular and invariant mass spectra for correlated Λp, Λd, Λt [8]. Possible DBKNS may be produced with K− stopped in helium or carbon and then decay into considered decay channels. The experiment was carried out with very high precision and high acceptance by AMADEUS using the KLOE detector itself as an active target (2004-2005) as well as with dedicated high purity graphite target (2012) and using low-energetic negatively charged kaon beam provided by DAΦNE collider located in National Laboratory in Frascati (Italy). The poster will present status of the data analysis. [1] S. Wycech, Nucl. Phys. A 450 399c (1986); [2] Y. Akaishi, T. Yamazaki, Phys. Lett. B 535 70 (2002); [3] A. Dote, T. Hyodo, W. Weise, Phys. Rev. C 79 014003 (2009); [4] N. V. Shevchenko, A. Gal, J. Mares, Phys. Rev. Lett. 98 082301 (2007); [5] Y. Ikeda, T. Sato, Phys. Rev. C 79 035201 (2009); [6] A. E. Nelson and D. B. Kaplan, Phys. Lett B 192 193 (1987); [7] A. Scordo, et al., AIP Conf. Proc. 1735 080015 (2016); [8] C. Curceanu, et al., Acta Phys. Polon. B 46 203 (2015).

Speaker: Ms Magdalena Skurzok (Jagiellonian University)

61 Study of alpha cluster states in light nuclei for nuclear physics and astrophysics¶

% Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speakers: Dr Aliya Nurmukhanbetova (National Laboratory Astana, Nazarbayev University, Astana, 010000,Kazakhstan), Mr Dosbol Nauruzbayev (National Laboratory Astana, Nazarbayev University, Astana, 010000,Kazakhstan)

62 Sub-barrier fusion cross section measurements with STELLA¶

The STELLA (STELlar LAboratory) experimental station for the measurement of sub-barrier light heavy ion fusion cross sections has been commissioned at the Androm\`{e}de accelerator at IPN, Orsay. These measurements can yield both insight into nuclear cluster effects~[1] and the $S$-factors at energies of astrophysical interest. In particular, ${}^{12}$C+${}^{12}$C fusion was identified as a key reaction on the production route of heavier elements in massive stars during the carbon burning phase, in type Ia supernovae and in superbursts from accreting neutron stars~[2]. Since sub-barrier fusion reactions are strongly hindered by Coulomb repulsion, the experimental determination of these cross sections ($\sim$~nb) is highly challenging. Nowadays, the determination of such cross sections is targeted with coincidence measurements using the so called gamma-particle-technique~[3]. The STELLA setup comprises a set of DSSSDs as well as an array of LaBr${}_3$ detectors from the UK FATIMA collaboration (FAst TIMing Array) for charged particle and gamma recognition, respectively. In addition, a rotating target mechanism is developed to sustain beam intensities $>10\mu$A. In this contribution, the experimental layout will be introduced in detail with a focus on the design and performance of LaBr${}_3$ detection array. Furthermore, the measurement technique will be sketched with first results from the commissioning campaign using ${}^{12}$C beam. [1] D.~Jenkins and S.~Courtin, Phys. Jour. G 42, 034010 (2015); [2] L.R.~Gasques \textit{et al.}, PRC 76, 3, 035802 (2007); [3] C.L.~Jiang \textit{et al.}, NIM A 682, 12 (2012);

Speaker: Prof. Sandrine Courtin (IPHC Strasbourg)

63 The Measurement of Long Lived Alpha Decay for Cosmochronometry¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Mr Heinrich Wilsenach (TU-Dresden, IKTP)

64 The role of 13C excited states in α+9Be reaction and scattering cross sections¶

The study of ${}^{13}$C structure allows to understand the effects of clusterization in light non-self-conjugated nuclei. The possible presence of rotational bands built on molecular states has been suggested in several papers [1,2]. Furthermore, in recent times, some theoretical papers [3,4] predicted the possible existence of states corresponding to the coupling of a valence neutrons to the ${}^{12}$C Hoyle state. To shed light on these aspects, we performed a comprehensive $R$-matrix fit of $\alpha {+}^9$Be elastic (${\alpha }_0$) and inelastic (${\alpha }_1$ and ${\alpha }_2$) scattering data in the energy range E$\simeq$ 3.5 – 10 MeV at several angles [5]. To carefully determine the partial decay widths of states above the $\alpha$ decay threshold we included in the fit procedure also ${}^9$Be($\alpha ,n_0$)${}^{12}$C${}_{gs}$ and ${}^9$Be($\alpha ,n_1$)${}^{12}$C${}_{4.44}$ cross section data taken from [6,7]. This analysis allows to improve the (poorly known) spectroscopy of excited states in ${}^{13}$C in the E${}_x\simeq$12-17 MeV region [8]. Furthermore, a better knowledge of high-energy resonance parameters (especially for broad states) can improve low-energy extrapolations of the ${}^9$Be($\alpha ,n$)${}^{12}$C reaction $S$-factor, that plays a key role in the description of ${}^{12}$C nucleosynthesis during a supernova explosions [7,9]. Preliminary results of these studies will be discussed. \bigskip {\small \noindent [1] M. Milin and W. von Oertzen, Eur. Phys. J. A 14 (2202) 295.\\ \noindent [2] N. Furutachi and M. Kimura, Phys. Rev. C 83 (2011) 021303(R).\\ \noindent [3] T. Yamada and Y. Funaki, Phys. Rev. C 92 (2015) 034326.\\ \noindent [4] Y. Chiba and M. Kimura, J. Phys.: Conf. Ser. 569 (2014) 012047.\\ \noindent [5] I. Lombardo et al., Nucl. Instr. Meth. Phys. Res. B 302 (2013) 19.\\ \noindent [6] L. van der Zwan and K. W. Geiger, Nucl. Phys. A 152 (1970) 481.\\ \noindent [7] R. Kunz et al., Phys. Rev. C 53 (1996) 2486.\\ \noindent [8] M. Freer et al., Phys. Rev. C 84 (2011) 034317.\\ \noindent [9] S.E. Woosley and R.D. Hoffman, Astrophys. J. 395 (1992) 202.\\

Speaker: Dr Ivano Lombardo (Università di Napoli Federico II and INFN - Sez. Napoli)

65 Treatment of isomers in nucleosynthesis codes¶

Isomers are metastable states of atomic nuclei. Their half-lifes are about 100 to 1000 times longer than those of the excited nuclear states with prompt g-emissions. If the conditions in an application change on the time scale of isomers' half lifes, their abundances have to be tracked explicitly. The high temperatures under stellar conditions enable the population of higher-lying states via thermal excitations. These states either decay back or populate different states, e.g isomers. Isomers are particular important if their $\beta$-decay rates differ amongst each other. As a result, the effective life-time of an isotope under stellar conditions can differ dramatically from terrestrial conditions. In stellar nucleosynthesis codes, environmental conditions change on time scales ranging from milliseconds during explosions to millions of years during the burning phases. Hence, the treatment of isomers depends on the investigated scenario. We will present a general approach to the treatment of isomers in hot, thermalized environments with a special emphasis on the impact on stellar nucleosynthesis. Important examples like ${}^{26}$Al and ${}^{85}$Kr will be discussed.

Speaker: Prof. Rene Reifarth (Goethe University Frankfurt)

66 “Development and use of CR39 Nuclear Track Detectors for the Measurement of the Interaction of (High Flux) Neutron Beams with 7Be and the Primordial 7Li problem¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% The high intensity epithermal neutron beams produced by the Soreq Applied Research Accelerator Facility (SARAF) operating with the Liquid Lithium Target (LiLiT) present significant opportunities in Nuclear Astrophysics. However, major experimental challenges arise when a detector is used with the high flux 50 keV quasi-Maxwellian neutron beams produced by the LiLiT ($\sim {10}^{10}$ n/sec/cm${}^2$) as well as the high flux ($\sim {10}^{11}$ /sec) of 477 keV gamma-rays from the ${}^7$Li(p,p'$\gamma$) reaction. We are developing protocols [1] for the use of CR39 Nuclear Track Detectors (NTD) in such high intensity backgrounds. We calibrated CR39 NTD with alpha-particles from standard radioactive sources and by using Rutherford Backscattering of accelerated alpha-particles and protons from a thin gold foil. We used cold neutrons to calibrate ``the background" ${}^{17}$O(n,$\alpha$) reaction that occurs inside the CR39 plates. The plates were etched in a standard 6.25 N NaOH solution for 30 minutes at 90${}^{\circ }$C to produce micron size circular pits. The plates were scanned with a fully motorized microscope. A segmentation algorithm that addresses the challenges posed by the intense neutron beam and gamma-ray background was developed. We used a (``phantom") ${}^9$Be target produced at the Paul Scherrer Institute(PSI) [2] to measure the background from irradiation with an intense ($\sim {10}^{10}$ n/cm${}^2$/sec) neutron beam. Using our calibration we define the radii region of interest (RRI) for detecting alpha-particles and we demonstrate that it is governed by pits generated by the combination of 1.4 - 1.7 MeV alpha-particles and 0.6 - 0.3 MeV ${}^{14}$C from the ${}^{17}$O(n,$\alpha$)${}^{14}$C reaction that occurs inside the CR39. These backgrounds are the limiting factor in measuring small cross sections with the current setup, as for example is required in the study of the interaction of neutrons with ${}^7$Be, which is important for understanding the ``Primordial ${}^7$Li Problem" [3]. \\ \ \\ ${}^{\ast }$ Work supported by the U.S.-Israel Bi National Science Foundation, Award Number 2012098, and the U.S. Department of Energy, Award Number DE-FG02-94ER40870. \bigskip {\small \noindent [1] Emily Elizabeth Kading {\em et al.}, to be published, Jour. Instr. (2017). \noindent [2] Emilio Andrea Maugeri {\em et al.}, in press, Jour. Instr. (2017) \noindent [3] Moshe Gai, Invited Talk, this conference. %%% %%% End of abstract. %%% \end{document}

Speaker: Emily Kading (Graduate Student)

Abstract E_Kading_NPA8_Abstract.pdf

Wednesday, 21 June ¶

Nuclear astrophysics with lasers¶

67 Nuclear physics and astrophysics ELI-NP: The emerging future¶

The mission of the Extreme Light Infrastructure Nuclear Physics (ELI-NP) research infrastruc- ture are nuclear physics studies with high-power lasers and high-brilliance quasi-monochromatic gamma beams [1,2]. The laboratory will become operational as an user facility in 2019. Two high-power lasers will provide laser pulses on target, each of them having three outputs, e.g. of100TWat10Hz,1PWat1Hzand10PWonceperminute. Thetwolaserarmswillbe synchronized and it will be possible to deliver any combination of these pulses on target, since each output will be provided with its own amplifier [3]. In addition, a high-brilliance narrow- bandwidth gamma beam will be produced at ELI-NP via Compton backscattering of laser light off electrons accelerated to relativistic energies [4]. The 100 Hz electron bunches will be delivered by an electron linac, where they will be accelerated up to energies of 750 MeV. There will be two interaction points where the electrons will collide with laser pulses provided by 0.2 J 100 Hz Yb:YAG lasers. At one of them, a low-energy gamma beam will be produced, with energies up tp 3.5 MeV, and at the other one the maximal energy of the gamma beam will reach 19.5 MeV. Each electron bunch will consist of a train of 32 microbunches and laser re-circulators will be used at the interaction points to ensure the interaction of the laser pulse with each of the bunches in the train. Thus, gamma beams of spectral density of 104 photons/s/eV will be produced, which after collimation results in highly polarized (¿ 95%)quasi-monochromatic gamma beams (bandwidth le0.5%) with beam intensities of 1010 photons/s, or ∼ 109 per microbunch. Several types of experiments will be possible at ELI-NP, e.g. laser-driven experiments in single or double pulse-shot mode on target, gamma-beam experiments in narrow- or wide- bandwidth mode, and combined laser- and gamma-beam experiments. Thus, the ELI-NP labo- ratory opens a new dimension for nuclear physics studies with intense electromagnetic probes. The experimental program, which is under preparation at ELI-NP targets all these experimental modes and at present a large variety of instruments are under construction [2,5,6]. The present status of the implementation facility, as well as the emerging experimental program in the field of nuclear physics and astrophysics will be described, with an emphasis of the considered day-one experiments. [1] N. V. Zamfir, Nucl. Phys. News 25:3 34 (2015); [2] S. Gales et al., Phys. Scr. 91 093004 (2016); [3] N. V. Zamfir, Eur. Phys. J. Special Topics 223 1221 (2014) [4] O. Adriani et al., arXiv:1407.3669 [physics.acc-ph] (2014); [5] ELI-NP TDR teams, Rom. Rep. Phys. 68S (2016) (www.rrp.infim.ro); [6] D. L. Balabsnki et al., Europhys. Lett. 117 28001 (2017).

Speaker: Prof. Dimiter Balabanski (ELI-NP/IFIN)

68 Investigating nuclear reactions at astrophysical energies with gamma-ray beams and an active-target TPC¶

A new methodology to measure cross-sections for thermonuclear reactions that power the stars is being developed at the University of Warsaw. These reactions take place at different energies according to the respective stellar environment. Such energies are well below the Coulomb barrier and the respective cross-sections are incredibly small, often below the experimental reach. There is a lack of experimental data on cross-sections for low-energies, information that is indispensable for modelling energy production in stars. As a consequence, extrapolations are made, with their unavoidable large uncertainty. Of special interest are (p,gamma) and (alpha,gamma) reactions, in particular those, that regulate the ratio of C and O and those that burn 18O and, therefore, regulate the ratio between 16O and 18O in the Universe. One of the benchmark reactions to be investigated in this work is the 12C(alpha,gamma)16O at energies down to 1 MeV in the centre-of-mass reference frame. We propose to use a gaseous active target detector to study (alpha,gamma) and (p,gamma) nuclear reactions of current astrophysical interest by means of studying time-inverse photo-disintegration processes induced by high energy photons. The advantage of such an approach stems from the fact that photons are not subject to the nuclear Coulomb barrier. The Extreme Light Infrastructure-Nuclear Physics facility (ELI-NP) - currently being built near Bucharest, Romania - will deliver monochromatic, high-brilliance and polarized gamma-ray beams. The charged products of photodisintegration reactions will be measured by means of a Time Projection Chamber (ELITPC) with 3-coordinate (u-v-w) planar electronic readout acting as virtual pixels. The detector will be equipped with triple-GEM structure for gas amplification and will work at lower-than-atmospheric pressure. The concept of the detector and the status of the R&D for it will be presented, as well as results from tests using a scaled demonstrator detector.

Speaker: Dr Chiara Mazzocchi (University of Warsaw)

Slides Mazzocchi.pdf

69 Fusion plasmas and neutron production from the interaction of D2 and CD4 clusters with contrast upgraded Texas Petawatt laser¶

Nuclear fusion from the interaction of very high intensity laser pulses and nm-scale deuterium clusters has been studied since 1999 [1]. These van der Waals bonded clusters can be easily produced in the expansion of a gas jet into vacuum. They absorb the laser pulse energy very efficiently (approaching 100% under certain conditions) and the process by which the ions attain high kinetic energies has been well explained by the Coulomb explosion model. Using these energetic exploding clusters, it is possible to create fusion plasmas with ion temperatures of many keV at densities of up to 1019 cm−3. DD fusion events occur between ions or when energetic ions collide with cold atoms in the background gas jet. As a result of both of these fusion reactions, quasi-monoenergetic 2.45 MeV neutrons are produced from the localized fusion plasma in a sub-nanosecond burst becoming an attractive bright, short, and localized neutron source potentially useful for material damage. These plasmas have been exploited to measure the astrophysical S factor for the 3He(d,p)4He fusion reaction at temperatures of few keV by irradiating a D2-3He mixture [2]. In this talk, I will review several experiments performed using the Texas Petawatt laser to measure astrophysical S-factors [3] and to optimize the neutron yield using D2 and CD4 clusters where 2·107n/shot were achieved [4]. Previous experiments showed a drop in the ion temperature with high laser intensities suggesting laser pre-pulses could be breaking the clusters before arrival of the main pulse [5]. In 2015, the Texas Petawatt laser underwent a major upgrade to its pulse contrast to reduce the intensity of pre-pulses [6]. I will present our recent results in neutron yield with the contrast upgraded Texas Petawatt laser and discuss measurements of the ion range in cluster media that we found differs considerably from that of homogeneous gases [7]. [1] T. Ditmire et al., Nature (London) 398, 489 (1999). [2] M. Barbui et al., Phys. Rev. Lett. 111, 082502 (2013). [3] D. Lattuada et al., Phys. Rev. C 93, 045808 (2016). [4] W. Bang et al., Phys. Rev. E 87, 023106 (2013). [5] W. Bang et al., Phys. Rev. E 87, 023106 (2013). [6] E. Gaul et al., J. Phys. Conf. Ser. 717, 012092 (2016). [7] G. Zhang et al., Phys. Lett. A 381, 1682 (2017).

Speaker: Dr Hernan J. Quevedo (University of Texas)

70 Measurements Of Stellar And Big-Bang Nucleosynthesis Reactions Using Inertially-Confined Plasmas¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Alex Zylstra (Los Alamos National Laboratory)

71 Nuclear Astrophysics at ELI-NP: the ELISSA prototype tested¶

The Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility, under construction in Magurele near Bucharest in Romania, will provide high-intensity and high-resolution gamma ray beams that can be used to address hotly debated problems in nuclear astrophysics, such as the accurate measurements of the cross sections of the 24Mg( ,)20Ne reaction, that is funda- mental to determine the effective rate of 28Si destruction right before the core collapse and the subsequent supernova explosion [1], and other photo-dissociation processes relevant to stellar evolution and nucleosynthesis [2]. For this purpose, a silicon strip detector array (named ELISSA, acronym for Extreme Light In- frastructure Silicon Strip Array) will be realized in a common effort by ELI-NP and INFN-LNS (Catania, Italy), in order to measure excitation functions and angular distributions over a wide energy and angular range. According to our simulations, the final design of ELISSA will be a very compact barrel configuration, leaving open the possibility in the future to pair a neutron detector with the array. The kinematical identification will allow to separate the reaction of interest from others thanks to the good expected angular and energy resolutions. A prototype of ELISSA was built and tested at Laboratori Nazionali del Sud (INFN-LNS) in Catania with the support of ELI-NP. In this occasion, we have carried out experiments with alpha sources and with a 11 MeV 7Li beam. We used X3 and QQQ3 silicon-strip position sen- sitive detectors manufactured by Micron Semiconductor ltd. Thanks to our approach, the first results of those tests show up a very good energy resolution (better than 1%) and very good position resolution, of the order of 1 mm. At very low energies, below 1 MeV, a worse position resolution is found, of the order of 5 mm, but still good enough for the measurement of angular distribution and the kinematical identification of the reactions induced on the target by gamma beams. Moreover, a threshold of 150 keV can be easily achieved with no cooling. We will discuss technical details of the detector and present results regarding Monte Carlo simulation, energy resolution and detection thresholds of ELISSA, the physical cases to be investigated. To sum up, these tests allow us to say that the X3 detectors, as well the standard QQQ3 detec- tors, are perfectly suited for nuclear astrophysics studies with ELISSA. In particular, ELISSA will allow us to determine a much more accurate cross section for the 24Mg photodissociation to be used in nuclear reaction network calculations to improve the knowledge of the pre-supernova chemical composition.

Speaker: Giovanni Luca Guardo (LNS)

72 Monte Carlo simulation of photonuclear reactions of astrophysical interest with intense gamma sources¶

Monte Carlo simulation of photonuclear reactions of astrophysical interest with intense gamma sources

Speaker: Dr Dario Lattuada (LNS)

11:00 Coffee break

RIBs in nuclear astrophysics 2¶

73 Studies of X-ray burst reactions with radioactive ion beams from RESOLUT¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Jeffery Blackmon (Louisiana State University)

74 Improved experimental determination of the branching ratio for beta-delayed alpha decay of N-16¶

While the C-12(alpha,gamma)O-16 reaction plays a central role in nuclear astrophysics, the cross section is too small at the energies relevant to stellar helium burning to be directly measured in the laboratory. The beta-delayed alpha spectrum of N-16 can be used to constrain the astrophysical S-factor, but with this approach the S-factor becomes strongly correlated with the assumed alpha-decay branching ratio. Using two different experimental techniques, we have obtained consistent values for this branching ratio which, however, deviate significantly from the accepted value. Here, we report on our findings and discuss the implications for the determination of the astrophysical S-factor of the C-12(alpha,gamma)O-16 reaction.

Speaker: Dr Oliver Kirsebom (Department of Physics and Astronomy, Aarhus University)

Slides Kirsebom.pdf

75 Cousin of the Hoyle state: Observation of a narrow resonance above 13N+2p threshold¶

The existence of the Hoyle state is crucial for the nucleosynthesis of the chemical elements heavier than lithium. This state has been the subject of many theoretical studies and philosophical discussions (anthropic principle). The existence of this remarkable state could be explained by the Ikeda conjecture [1,2]. The latter can be formulated simply: The coupling to a nearby cluster decay channel induces cluster correlations in nuclear wave functions. The Hoyle state resides just above the threshold for decay into 8Be and an alpha particle. The Ikeda conjecture implies that the Hoyle state should have an alpha cluster structure. We performed a study of the unbound nucleus 15F. Intense and pure radioactive beam of 14O, produced at GANIL (France) with the SPIRAL1 facility, was used to study the 15F low-lying states [3]. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the resonance corresponding to the second excited state (J=1/2-) was measured with a width of only 36(5)(14) keV. This state is precisely located just above the two-proton threshold. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a 12C core and three valence protons. It is found that it is an almost pure wave function of two-proton cluster. [1] K. Ikeda et al., Prog. Theor. Phys. Suppl., Extra Number, 464(1968). [2] J. Okołowicz, M. Płoszajczak and W. Nazarewicz. Progress of Theoretical Physics Supplement 196, 230 (2012). 65, 100 [3] F. de Grancey et al., Physics Letters B758 (2016)26–31

Speaker: Dr François de Oliveira Santos (GANIL)

76 Key Resonances in 35Ar and their importance for determining the origin of presolar grains¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Ms Ralitsa Ilieva (University of Surrey)

77 Observation of the 2+ rotational excitation of the Hoyle state¶

We present the first clear observation of the 2+ rotational excitation of the Hoyle state in a beta decay experiment. Coincident detection of β-3α particles from the cascade 12N(β)12C(α1)8Be(α2)α3 have been used to obtain β-α1 angular correlation, which then has been used to determine the strength of the 2+ state relative to that of the 0+ in the 9-12 MeV energy region. The experiment has been performed at the IGISOL facility at JYFL, Jyväskylä, Finland. This second 2+ state of the 12C nucleus is of great importance to nuclear astrophysics reaction rate calculations and also to nuclear cluster structure studies. The triple-α process, which is responsible for 12C production, primarily proceeds through a resonance in the 12C nucleus, famously known as the Hoyle state. The cluster nature of the Hoyle state allows the formation of a rotational band built upon it. The first member of the band is thought to be in the 9-11 MeV region, with Jπ=2+ [1-4], with the most recent data indicating an energy of 10.03 MeV [5]. Further knowledge of this state would help not only to understand the debated structure of the 12C nucleus in the Hoyle state, but also to determine the high-temperature (> 1 GK) reaction rate of the triple-α process more precisely [6,7]. The precise evaluation of the rate of this reaction is required to be able to understand the final stages of stellar nucleosynthesis and the elemental abundances in the universe. Due to the significance of the resonance, a reconciliation of the data from different available probes is highly desirable. We therefore, for the first time, present a clean identification of the 2+ resonance populated in beta decay through application of the novel technique of beta-triple-alpha coincidence studies. We further discuss the impact of the resonance on high-temperature astrophysical scenarios. [1] H .O. U. Fynbo, C. Aa. Diget, Hyperfine interactions 223, 1-3 (2014); [2] S. Hyldegaard et al., Phys. Rev. C 81, 024303 (2010); [3] M. Itoh et al., Phys. Rev. C 84, 054308 (2011); [4] M. Freer et al., Phys. Rev. C 80, 041303(R) (2009); [5] W. R. Zimmerman et al., Phys. Rev. Lett. 110, 152502 (2013); [6] C. Angulo et al., Nucl. Phys. A 656, 3 (1999); [7] R. H. Cyburt et al., Astrophys. J. Suppl. Ser. 189, 240 (2010).

Speaker: Ms Ruchi Garg (University of York)

78 Measurement of 21Na(α,p)24Mg cross section for the study of 44Ti production in supernovae.¶

While core collapse supernovae have long captured the attention of physicists and astronomers, surprisingly little is currently known about the nature of the explosion mechanism. This is due to the complexity of the explosion, the large computational requirements for even 2D simulations, and the lack of precise nuclear physics inputs to these models. One of the few methods by which this explosion mechanism might be studied is through a comparison of the amount of 44Ti observed by space based γ-ray telescopes and the amount predicted to have been generated during the explosion. For these comparisons between observations and models to be made, however, more precise nuclear physics inputs are required. The reaction 21Na(α,p)24Mg has been identified as one of the key reactions affecting the 44Ti mass fraction by factors of 10 or more. There are currently no published data on this reaction. A direct experimental measurement of the 21Na(α,p)24Mg cross section has been carried out at TRIUMF, Canada. This experiment utilised the TUDA facility at ISAC-I. The 21Na radioactive beam, at high intensity, impinged on a 2cm wide gas target, containing 100 torr of 4He. A downstream silicon array, consisting of a dE-E telescope, detected the reaction protons. An upstream silicon array measured beam back-scattered from a Au foil located at the entrance of the gas target, for normalisation. Data were collected at four laboratory energies covering Ecm=3.2-2.5 MeV, which is approximately the top half of the 2GK Gamow Window. Preliminary analysis results will be presented, along with details of the experimental challenges encountered and the steps taken to overcome them.

Speaker: Dr Alison Laird (University of York)

13:30 Lunch

Social excursion¶

Thursday, 22 June ¶

Stellar models¶

79 Hydrostatic and Explosive Nucleosynthesis in Massive Stars¶

Speaker: Dr MARCO LIMONGI (INAF-OAR)

Slides Limongi.pptx

80 s process in massive stars: theoretical predictions and nuclear and stellar uncertainties¶

After introducing the slow neutron capture process in massive stars, the so-called weak s process, I will present recent theoretical predictions for the weak s process covering a wide range of initial masses and metallicities. I will in particular discuss the strong effects of rotation at low metallicities and how they boost the weak s process. I will then compare the predictions to observations and discuss the key nuclear and stellar uncertainties involved. I will end with conclusions and future outlook.

Speaker: Dr Raphael Hirschi (Keele University)

Slides Hirschi.pdf

81 A unique mechanism to account for well known peculiarities of AGB star nucleosynthesis¶

We present here the application of a model for a mass circulation mechanism in between radia- tive layers and the base of the convective envelope of low mass AGB stars, aimed at studying peculiar aspects of their nucleosynthesis. Until recently the observational evidence that s-process elements from Sr to Pb are produced by stars ascending the second giant branch could not be explained by self-consistent models, forcing researchers to extensive parameterizations. The cru- cial point is to understand how protons can be injected from the envelope into the He-rich layers, yielding the formation of 13C and then the activation of the 13C(α,n)16O reaction. On the other hand, a mass circulation mechanism in between the H-burning shell and the convective envelope is belived to account for the peculiar abundances of light nuclei (from 3He to 26Mg) observed in low mass AGB stars [1]. Also in this case, despite more than twenty years of studies, we still have not achieved a final statement on the physical process responsible for the mass transportation. The mixing scheme we present is based on a previously suggested magnetic-buoyancy process [2]. We show the ”magnetic” mass transport to account adequately for both the formation of the main neutron source for s-processing in low mass AGBs [3] and the peculiar abundances of light nuclei observed in these stars. In particular our analysis results are focused on addressing the constrains to AGB nucleosynthesis coming from the isotopic composition of presolar grains recovered in meteorites [4,5]. We find that (i) n-captures driven by the magnetically-induced mixing can account for the isotopic abundance ratios of s-elements recorded in presolar SiC grains as well as (ii) the most extreme levels of 18O depletion and high concentration of 26Mg (from the decay of 26Al) shown by corundum (Al2O3) grains. [1] G. J.Wasserburg, A. I. Boothroyd, I.-J. Sackmann, ApJ 447 L37 (1995); [2] M. C. Nucci & M. Busso ApJ, 787 141 (2014); [3] O. Trippella, M. Busso, S. Palmerini, et. al., ApJ 818 125 (2016); [4] S. Palmerini, O. Trippella, M. Busso, MNRAS, in press (2017); [4] S. Palmerini, O. Trippella, M. Busso, et al. GCA, submitted.

Speaker: Sara Palmerini (PG)

10:10 Coffee break

Special session: celebrating Claudio Spitaleri¶

82 The origins of the THM¶

Speaker: Marcello Lattuada (LNS)

83 TBD¶

Speaker: Silvio Cherubini (LNS)

84 And so it all began: Personal memories of the man behind the scientist¶

At the time I began my scientific career as a PhD student under Prof Claudio Spitaleri’s supervision, the Trojan Horse Method was still in its infancy. Like with any new-born idea, it took time and effort and passion to plant the early seeds that would eventually develop into a now well-established method in nuclear astrophysics research. In this talk I will offer my own recollection of those early years as a personal tribute to Claudio's unique mix of human traits that shaped our professional relationship for decades to come.

Speaker: Prof. Marialuisa Aliotta (University of Edinburgh)

85 Theory of the Trojan-Horse Method - From the original idea to actual applications¶

Breakup reactions were proposed in 1986 by Gerhard Baur as an indirect method to investigate low-energy charged-particle reactions relevant for nuclear astrophysics [1]. This so-called 'Trojan-Horse method' (THM) allows to extract cross sections of two-particle reactions from suitable transfer reactions with three particles in the final state using quasifree scattering conditions. A specific feature of the approach is the suppression of the Coulomb barrier effect that causes a strong reduction of the cross section of astrophysical reactions at low energies. The THM is applicable to general rearrangement reactions in contrast to other indirect techniques such as the Coulomb dissociation (CD) method or asymptotic normalization coefficient (ANC) method, which aim at radiative capture reactions. The analysis of dedicated laboratory experiments using the THM requires the application of nuclear reaction theory. In this contribution, the development of the theoretical description is presented starting from the early ideas with simple approximations, e.g., a modified plane-wave impulse approximation (PWIA) that allowed to factorize the THM cross section as a product of a kinematic factor, a momentum distribution and a half-off-shell two-body cross section. Different applications are considered, in particular, elastic scattering, non-resonant and resonant reactions. Suggestions for possible improvements in the future development of the theory are given. [1] G. Baur, Phys. Lett. B 178, 135 (1986).

Speaker: Dr Stefan Typel (IKP, Technische Universität Darmstadt)

Slides Typel.pdf

86 Clustering of light nuclei and electron screening in astrophysical environments (EPS Invited Speaker)¶

Accurate measurements of nuclear reactions of astrophysical interest within, or close to, the Gamow peak show evidence of an unexpected effect attributed to the presence of atomic electrons in the target. The experiments need to include an effective “screening” potential to explain the enhancement of the cross sections at the lowest measurable energies. Despite various theoretical studies conducted over the past 20 years and numerous experimental measurements, a theory has not yet been found that can explain the cause of the exceedingly high values of the screening potential needed to explain the data. In this talk I will show that instead of an atomic physics solution of the “electron screening puzzle”, the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.

Speaker: Prof. Carlos Bertulani (Texas A&amp;M University-Commerce)

Slides Bertulani.pdf

87 Coulomb dissociation - another Trojan Horse¶

I start with my experience for the quasi-free process, which is on the 1H(d,2He)n reaction, where 2He denotes a system of two protons in their unbound singlet S state. The data taken at Saturne in late 1980s were analyzed with plane-wave impulse approximation. The tensor analyzing powers and even the absolute magnitudes of the differential cross sections have been successfully explained. That was my surprise, because nucleon rearrangement reactions are not always described by such a simple treatment. The second time when I encountered such unexpected (to my view) success is the occasion when I heard a talk by Prof. Spitaleri on the Trojan Hourse determination of astrophysical reactions. The process is a “quasi-free reaction” leaving a three-body final state with a particle-unbound subsystem. A remarkable agreement between the excitation functions of the original and extracted reaction of interest was demonstrated, at least, in that case, for their relative energy-dependence. It should be noted that the incident energy is not very high and complicated processes could contribute. These observations lead me a “feeling”: the quasi-free mechanism can naturally find a way to particle-unbound final state, while population of discrete bound-states requires more kinematically restricted conditions and may allow for complicated mechanism to be involved. That is only my prejudice, but we should thank this favorable situation. The Trojan Hourse method can indirectly access particle rearrangement reactions of astrophysical interest. Another indirect method that can study radiative capture, often of importance in nucleosynthesis, is the Coulomb dissociation. I conducted several experiments in the period when Prof. Spitaleri vigorously studied and were establishing the Torojan Hourse method. Coulomb dissociation, that is inelastic scattering exciting a nucleus to its unbound state, is often explained in terms of virtual photons created when the two colliding nuclei come close to each other. In fast collisions, the breakup process involves a single photon and can therefore be understood as a Trojan Horse reaction, where the photon serves as a "soldier". Several radiative capture reactions of astrophysical interest have been studied. Especially with fast radioactive-isotope (RI) beams, processes involved in explosive nuclear burning, such as the hot CNO cycle and rp-process, could be accessed.

Speaker: Dr Tohru Motobayashi (RIKEN Nishina Center)

Slides Motobayashi.pdf

88 Subtilities in Stars: Indirect Evidence of Mixing Married to Indirect Nuclear Physics Methods¶

Speaker: Maurizio Busso (PG)

89 "Other" indirect methods for Nuclear Astrophysics¶

In the house of Trojan Horse Method (THM), I will say a few words about "other" indirect methods we use in Nuclear Physics for Astrophysics. In particular those using Rare Ion Beams that can be used to evaluate radiative proton capture reactions. I addition a few words about work done with the Professore we celebrate today. With a proposal, and some results with TECSA, for a simple method to produce and use isomeric beam of 26mAl.

Speaker: Dr Livius Trache (IFIN-HH Bucharest)

90 Alpha-cluster structure populated in the resonance reactions induced by rare beams¶

Alpha-cluster structure populated in the resonance reactions induced by rare beams V.Z. Goldberg, G.V. Rogachev Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA The alpha clusterization manifests itself in remarkable and exotic structures in atomic nuclei. In particular, quasi rotational bands of levels with alternative parities and large alpha cluster reduced widths are well known in the light 4N nuclei (like 8Be, 12C, 16O...). The importance of this nuclear structure in astrophysics is also well recognized. Even if astrophysical reactions involving helium do not proceed through the strong α-cluster states, these states provide α width to the states that are closer to the region of astrophysical interest through configuration mixing. While the phenomenon is known, a detailed explanation in the framework of the N-N interaction is absent [1,2]. The scarce experimental data on the single particle properties of the cluster states is partly responsible for this situation. Indeed, the α decay threshold is much lower than the nucleon decay in 4N nuclei, and, therefore, nucleon decays cannot be practically observed from the members of the cluster bands. In N≠Z nuclei, the nucleon decay threshold is close to that for α particle, and the penetrability factors do not inhibit the nucleon decay from the states in question. It is also possible to use mirror resonance reactions and apply the powerful approach of isospin symmetry to the investigations involving N≠Z nuclei. Of course, such studies involve unstable (Z>N) nuclei. Therefore, the experiments are difficult and need a new technique to study resonance reactions. The first measurements of the resonance reactions involving a pair of N≠Z nuclei were made in Ref. [3]. Since then, a few attempts to develop the field were made (see [4,5]]. I will review the history, the problems, and the prospective of these studies. References 1. P.Navratil, J.P.Vary, B.R.Barrett Phys.Rev.Lett. 84,5729 (2000) 2. M.L.Avila, G.V.Rogachev, V.Z.Goldberg et al., Phys. Rev. C 90, 024327 (2014) 3. V.Z.Goldberg, G.V.Rogachev... C.Spitaleri et al., Phys.Rev. C 69, 024602 (2004) 4. C.Fu, V.Z.Goldberg, G.V.Rogachev et al., Phys.Rev. C 77, 064314 (2008) 5. E.D.Johnson, G.V.Rogachev, V.Z.Goldberg et al., J.Phys.:Conf.Ser. 205, 012011 (2010)

Speaker: Dr Vladilen Goldberg (Cyclotron Institute, Texas A&M University, College Station, Texas, USA)

13:30 Lunch

Indirect methods 1¶

91 THM measurements in nuclear astrophysics: recent results and future perspectives¶

Experimental nuclear astrophysics aims at measuring astrophysically relevant burning reaction cross sections at the corresponding Gamow energy. However, in spite of the improvements for measuring low-energy nuclear reaction cross sections, the Gamow energy region peak often remains far to be fully explored mainly in the case of charged-particles induced reactions. In such cases, both Coulomb barrier penetration and electron screening phenomena strongly affect the bare-nucleus cross section determination thus leaving extrapolation procedures as the only way for accessing the Gamow energy region. The Trojan Horse Method (THM) allows one to measure the bare-nucleus cross-section of an astrophysically relevant reaction a+x→c+C by properly selecting the quasi-free (QF) contribution of an appropriate reaction a+A→c+C+s, performed at energies well above the Coulomb barrier, where the nucleus A has a dominant x⊕s cluster configuration. Thanks to its momentum-energy prescription, THM allows to explore a wide energy window in the center of mass system a + x by only using a monoenergetic beam. Such advantage appears of great importance also in the case of nuclear reactions involving exotic nuclei or neutron induced reactions, thus justifying the recent THM application to well definite reactions involved in explosive or primordial nucleosynthesis. [1] Spitaleri C. et al., Phys. of Atomic Nuclei, 74, 1725 (2011) [2] Tribble, R. et al., Rep. Prog. Phys., 77, 106901 (2014)

Speaker: Livio Lamia (LNS)

92 Reaction production + AMS: An alternative method to study (d,alpha)26Al and (p,gamma)26Al reactions at low energies¶

It is well known the importance in Astrophysics of the reactions regarding 26Al. This radioisotope is presented for instance, in the stars where there is H, C and Ne fusion at high temperatures; as well it can be found inside meteorites where it can be deposited or to be created in situ [1]. Considering the importance of the 26Al nuclei, in this work are presented the rst results regard- ing a campaign of measurements related with this radioisotope production, taking advantage of two dierent facilities: rstable, the radionucleus is produced by means of irradiation of silicon and magnesium targets with light particles, in order to produce (d,alpha) and (p, gamma) reactions at low energies by using a CN-Van der Graaff accelerator. Once the enrichment with 26Al was made, the targets are analyzed in an AMS machine with the aim to obtain the 26Al/27Al ratios [2]. This values can later be used to approach the cross section of 26Al directly related with the reaction used for its production. With this alternative method, it is possible to measure very acceptable small cross sections of low energy reactions, due to the typical high resolution of AMS technique. In this work are presented our preliminary results for the 28Si(d,alpha)26Al reaction cross sections around 1.5 MeV [3] as well as the first approximations for the 25Mg(p,gamma)26Al reaction cross sections below 1 MeV. [1] J. Kndlseder et. al. Astron. And Astrophys. 344 (1999) 68. [2] A. Arazi, et. al., Phys. Rev. C 74, 025802 (2006). [3] V. Araujo-Escalona et. al., J. of Phys. Conf. Ser, 730 (2016) 1-7.

Speaker: LUIS ARMANDO ACOSTA SANCHEZ (CT)

93 Cross section measurement of 14N(p,gamma)15O using the activation method¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr György Gyürky (Institute for Nuclear Research (Atomki)

Slides Gyurky.pdf

94 Measurement of β-delayed protons from decay of 31Cl covering the Gamow window of 30P(p,γ)31S at typical nova temperatures¶

The thermonuclear runaway in classical novae proceeds through radiative proton capture re- actions (p,γ) involving proton rich sd-shell nuclei close to the dripline. Many of the capture reactions at typical peak nova temperatures of 0.2-0.4 GK are dominated by resonant capture. Therefore, the key parameters in understanding the astrophysical reaction rates are the energies, decay widths and spins of these resonances. One of the bottleneck reactions in the ONe nova nucleosynthesis is the radiative proton capture 30P(p,γ)31S. In absence of intense 30P radioactive beams, the experimental efforts for finding and studying the resonances in 31S have concentrated on using a variety of indirect methods. One indirect method with high selectivity is the allowed β-decay of the 3/2+ ground state of 31Cl which populates excited states in 31S, corresponding to l = 0 resonances (Jπ = 1/2+,3/2+) and l = 2 resonances (J π = 5/2+ ). An observation, or non-observation, of β -delayed protons or γ -rays from the levels with uncertain or contradicting spin assignments [1] will help constraining the possible astrophysically important states. The previous efforts on measuring β-delayed protons from the states of astrophysical interest in 31S (Ex ∼ 100−500 keV) have not been successful for the fact that these studies suffered from the intense β-background in the setups utilizing Silicon detectors [2,3]. Recently, high statistics measurement of β -delayed γ -rays from decay of 31 Cl identified a new candidate for a resonance in the middle of the Gamow window [4]. Since the new level is seen populated in β-decay, it opens possibility for determining the proton branching ratio, which is one of the pieces of information needed for the experimental determination of the experimental value of the resonance strength. We have done a measurement of β-delayed protons from 31Cl with the newly built and commissioned AstroBox2 detector, based on Micro Pattern Gas Amplifier Detector (MPGAD) technology [5]. An intense and pure beam of 31Cl was produced with the MARS separator at the Texas A&M University, and implanted and stopped inside the gas volume of the AstroBox2 for the decay study. In this experiment we suppressed the β-background down to 100 keV, allowing background free study of β-delayed proton emitting states in 31S throughout the whole Gamow window of the 30P(p,γ)31S reaction. In this contribution we describe our setup and present the results of the experiment. [1] C. Ouellet and B. Singh, Nucl. Data Sheets 114, 209 (2013); [2] A. Kankainen et al., Eur. Phys. J. A 27, 67 (2006); [3] A. Saastamoinen et al., AIP Conf. Proc. 1409, 71 (2011); [4] M.B. Bennett et al., Phys. Rev. Lett. 116, 102502 (2016); [5] A. Saastamoinen et al. Nucl. Instrum. and Meth. in Phys. Res. B 376 (2016) 357.

Speaker: Dr Antti Saastamoinen (Cyclotron Insitute, Texas A&amp;amp;M University)

Slides Saastamoinen.pdf

16:30 Coffee break

Indirect methods 2¶

95 Study of stellar nucleosynthesis using indirect techniques¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% Direct measurements of nuclear reactions of astrophysical interest can be a technical challenge. Alternative experimental techniques such as transfer reactions, inelastic scattering and charge-exchange reactions offer the possibility to study these reactions by using stable or radioactive beams. In this context, an overview of recent experiments that have been carried out in Orsay using these indirect techniques will be given. The experiments concern the study of key reactions occurring in massive stars and novae. \bigskip {\small \end{document}

Speaker: Dr Faïrouz Hammache (IPN-Orsay)

Slides Hammache.pdf

96 Measurements of the 20Ne+4He resonant elastic scattering for characterization of the 24Mg states at relevant excitations for carbon - carbon burning process¶

Detailed knowledge on complex spectroscopy of the ${}^{24}$Mg nucleus at excitation energies between 14 and 19 MeV has large impact on understanding of clustering in nuclei and on carbon - carbon burning, the ${}^{12}$C+${}^{12}$C fusion, in massive stars. The ${}^{12}$C+${}^{12}$C and ${}^{16}$O+${}^8$Be cluster structures (threshold energies are 13.9 and 14.1 MeV respectively) become active in this energy region mixing with already strong ${}^{20}$Ne+${}^4$He clustering (threshold energy is 9.3 MeV). Their interplay and effects of strong $\alpha$-clustering in ${}^{12}$C and ${}^{20}$Ne lead to unique structural properties and very complex spectroscopy of the ${}^{24}$Mg. In this energy region are expected to exist the band heads of a number of rotational bands associated with the ${}^{12}$C+${}^{12}$C cluster structure whose high spin members are identified at higher excitations. It is cruical to identify low spin members of these rotational bands to improve understanding of their origin. The ${}^{12}$C+${}^{12}$C clustering has a strong effect on the C-C burning which play an essential role in many astrophysical phenomena, both quiescent and explosive. Existing data in astrophysically relevant energy range show large discrepancies in the S-factors and substantial improvements in future direct measurements are required to make further progress. Indirect experimental approach through measurements of the ${}^{20}$Ne+${}^4$He resonant elastic scattering was used to search for ${}^{24}$Mg states which may increase C-C burning rate. Observation of the $0^{+}$ (or $1^{-}$) resonance at excitations between 15 and 18 MeV would strongly indicate enhanced reaction rate of the ${}^{12}$C+${}^{12}$C fusion while its non-observation would imply non-resonant nature of the C-C burning, and hence its reduced contribution in many stellar phenomena. Measurements of the ${}^{20}$Ne+${}^4$He excitation functions by use of the 36.07, 45.45 and 53.17 MeV ${}^{20}$Ne beams delivered by the PIAVE-ALPI facility of Laboratori Nazionali di Legnaro INFN and a thick ${}^4$He gas target which stops the beam in front of the detector were performed. This beam energy range corresponds to the ${}^{12}$C+${}^{12}$C relative energy range of prime importance for astrophysics. Scattered $\alpha$-particles were detected in large area highly segmented silicon strip detector telescope built of 20 $\mu$m thick $\mathrm{\Delta }$E SSSD and 1000 $\mu$m thick E DSSSD. Telescope was positioned at 0${}^o$. Detailed measurements of the beam energy loss and beam intensity, needed for an accurate data analysis, were performed. Elastic scattering excitation functions were extracted for data between -5${}^o$ and 5${}^o$ and normalized to previously taken data. Large number of overlapping resonances is detected in the excitation functions. Strong contribution of the inelastic scattering to the first excited ${}^{20}$Ne state was observed and further analysis was performed for data free of inelastic scattering events. Using all available results on ${}^{24}$Mg states at these excitations, attempts to fully characterize the observed resonances in the excitation functions in terms of spin, parity, width and partial widths were done using R-matrix calculations. No clear evidence for the $0^{+}$ or $1^{-}$ state was found. Obtained results show the limitations of performed experiment and give clue for improved experiment. Complementary measurements using resonant scattering technique with the ${}^{20}$Ne beam and low density ${}^4$He gas target which will provide high resolution data for larger angular range were recently performed at LNL INFN and obtained data are being analysed.

Speaker: Dr Neven Soic (Rudjer Boskovic Institute Zagreb Croatia)

Slides Soic.pptx

97 Study of the 10B(p, alpha)7Be reaction at astrophysical energy using the Trojan Horse Method¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} \begin{center} %%% %%% Title goes here. %%% \TITLE{Study of the ${}^{10}$B(p; $\alpha$)${}^7$Be reaction at astrophysical energy using the Trojan Horse Method }\\[3mm] %%% %%% Authors and affiliations are next. The presenter should be %%% underlined as shown below. %%% \AUTHORS{S.M.R. Puglia${}^1$, C. Spitaleri${}^{1,2}$, M. La Cognata${}^1$, L. Lamia${}^2$, C. Broggini${}^3$, A. Caciolli ${}^{3,4}$, N. Carlin ${}^5$, S. Cherubini ${}^{1,2}$, A. Cvetinovic ${}^1$ , D. Dell'Aquila ${}^{6,7}$, R. Depalo ${}^{3,4}$, M. Gulino ${}^{1,8}$, I. Lombardo ${}^{6,7}$, R. Menegazzo ${}^3$, M.G. Munhoz${}^5$, R.G. Pizzone${}^1$, G.G. Rapisarda ${}^{1,2}$, V. Rigato${}^9$, S. Romano${}^{1,2}$, M.L. Sergi ${}^1$, F.A. Souza ${}^5$, R. Spart\'a ${}^1$, A. Tumino${}^{1,8}$} %%% {\small \it \AFFILIATION{1}{INFN-Laboratori Nazionali del Sud, Catania, Italy} \AFFILIATION{2}{Dipartimento di Fisica e Astronomia, University of Catania, Catania, Italy} \AFFILIATION{3}{INFN-Padova, Padova, Italy} \AFFILIATION{4}{Dipartimento di Fisica, University of Padova, Padova, Italy} \AFFILIATION{5}{Departamento de Fisica Nuclear, Universitade de Sao Paulo, Brasil } \AFFILIATION{6}{Dipartimento di Fisica, University of Napoli, Napoli, Italy} \AFFILIATION{7}{INFN-Napoli, Napoli , Italy} \AFFILIATION{8}{Facolt\'a di Ingegneria e Architettura," Kore" University, Enna, Italy} \AFFILIATION{9}{INFN-Laboratori Nazionali di Legnaro, Legnaro, Italy} %%% \vspace{12pt} % Do not modify % Enter contact e-mail address here. \centerline{Contact email: {\it puglia@lns.infn.it}} \vspace{18pt} % Do not modify \end{center} %%% %%% Abstract proper starts here. %%% The study of the reactions involving boron is of particular importance in nuclear physics as well as in nuclear astrophysics. In nuclear physics, it is possible to investigate the ${}^{11}$C level that are presently poorly known. On the nuclear astrophysics side the reactions destroying boron are important for understanding the abundances of light elements in stellar interior; in particular ${}^{10}$B(p,$\alpha$)${}^7$Be reaction is the main responsible for ${}^{10}$B destruction in stars [1]. In such environments this p-capture process occurs at a Gamow energy of 10 keV, and takes places mainly through a resonant state (E${}_x$=8.701 MeV) of the compound ${}^{11}$C nucleus. Thus, a resonance right in the region of the Gamow peak is expected to significantly influence the behavior of the astrophysical S(E)-factor. The ${}^{10}$B(p, $\alpha$)${}^7$Be reaction was studied via the THM applied to the ${}^2$H(${}^{10}$B,$\alpha$${}^7$Be)n in order to extract the astrophysical S(E)-factor in a wide energy range, from 5 keV to 1.5 MeV.\\ Two set of data will be presented , one of the experiment at LNS in Catania [2] and the other one was performed at Pelletron Linac Laboratory (Departamento de Fisica Nuclear DFN) in Sao Paolo (Brazil), respectively at 24.5 MeV and 27 MeV ${}^{10}$B energy [3] . \\ \bigskip {\small \noindent [1] A.M. Boesgaard et al., Astrophys. Journ. 621, 991 (2005); \noindent [2] C. Spitaleri et al., Phys-ReV. C 90, 035801 (2014); \noindent [3] C. Spitaleri et al., Phys-ReV. C in press, (2017).} %%% %%% End of abstract. %%% \end{document}

Speaker: Sebastiana Maria Puglia (LNS)

98 19Ne Sheds Light on Novae Detection¶

Classical novae are the most common astrophysical thermonuclear explosion [1] and are thought to contribute noticeably to the galactic chemical evolution [2,3]. As one of the few environments that can be modeled primarily from experimental nuclear data, observations would provide a direct test for current hydrodynamic codes. 18F produced in the runaway is the strongest 𝛾-ray source [4] immediately after the outburst but reaction rates must be constrained further to predict its intensity. The 18F(p,α)15O reaction remains the largest uncertainty in constraining these rates as key nuclear states in the compound nucleus, 19Ne, are still not known despite previous experimental efforts. To resolve this, the most important levels close to the proton threshold were populated using the charge exchange reaction 19F(3He,t)19Ne at IPN, Orsay. A Split-pole spectrometer measured the tritons and identified the states of interest while a highly segmented silicon array detected alpha and proton decays from 19Ne over a large angular range and at a high angular resolution. The branching ratios and spin-parities of these important states were extracted from the experimental results and directly contradict previous measurements of the nucleus [5]. In addition to other recent studies [6-8], the results provided input parameters for a comprehensive set of theoretical R-matrix calculations that have realistically modeled the remaining uncertainty in the reaction rate. The newly proposed rate will be discussed, along with implications for future studies of 19Ne necessary to provide an answer to the detectability of classical novae. [1] M. J. Darnley et al., Mon. Not. R. Astron. Soc. 369, 257 (2006) [2] J. Jose and M. Hernanz, Astrophys. J. 494, 680 (1998) [3] A. Tajitsu et al., Nature 518, 381 (2015) [4] J. Jose and M. Hernanz. J. of Phys. G 34, R431 (2007) [5] D. W. Bardayan et al., Phys. Lett. B 751, 311 (2015) [6] S. Cherubini et al., Phys. Rev. C 92, 015805 (2015) [7] A. Parikh et al., Phys. Rev. C 92, 055806 (2015) [8] F. Boulay et al., (to be published)

Speaker: Mr Jos Riley (University of York)

Slides Riley.pdf

99 The direct 18O(p; gamma)19F capture and the ANC method.¶

Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy The direct 18O(p; °)19F capture and the ANC method. V. Burjan1, Z. Hons1, V. Kroha1, J. Mr¶azek1, ·S. Pisko·r1, A. M. Mukhamedzhanov2, L. Trache2, R. E. Tribble2, M. La Cognata3, L. Lamia3, G. R. Pizzone3, S. Romano3, C. Spitaleri3 and A. Tumino3;4 1 Nuclear Physics Institute of Czech Academy of Sciences, 250 68 ·Re·z, Czech Republic 2 Cyclotron Institute, Texas A&M University, College Station, TX 77843 3 Universitµa di Catania and INFN Laboratori Nazionali del Sud, Catania, Italy 4 Universitµa degli Studi di Enna "KORE", Enna, Italy Contact email: burjan@ujf.cas.cz The depletion of 18O via the (p; °) capture is competing with the (p; ®) capture during the CNO cycles in AGB stars. Despite the fact that the (p; ®) capture is dominant the (p; °) can play an important role in mixing stages of star evolution. Here, we attempted to determine the astrophysical S-factor of the direct part of the 18O(p; °)19F capture by the indirect method of asymptotic normalization coe±cients (ANC). We measured the di®erential cross section of the transfer reaction 18O(3He; d)19F at a 3He energy of 24.6 MeV. The measurement was realized on the NPI cyclotron in ·Re·z, Czech Republic, with the gas target consisting of the high purity 18O (99.9 %). The reaction products were measured by eight ¢E-E telescopes composed from thin and thick silicon surface-barrier detectors. The parameters of the optical model for the input channel were deduced by means of the code ECIS and the analysis of transfer reactions to 12 levels of the 19F nucleus up to 8.014 MeV was made by the code FRESCO. The deduced ANCs were then used to specify the direct contribution to the 18O(p; °)19F capture process and compared with two experimental works.

Speaker: Dr Vaclav Burjan (Nuclear Physics Institute, CAS)

Slides Burjan.ppt

Visit of LNS¶

21:00 Banquet

Friday, 23 June ¶

Experimental techniques for nuclear astrophysics¶

100 Novel Nuclear Astrophysics Instruments¶

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Speaker: Dr Emanuel Pollacco (CEA - Saclay)

101 X-ray burst studies with the JENSA gas jet target¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Konrad Schmidt (National Superconducting Cyclotron Laboratory, East Lansing, MI, USA)

102 Constraining the stellar 124Xe(p,g) rate using the ESR storage ring at GSI¶

Charged-particle reactions, like (p, g) or (a, g), play a crucial role in many different astrophysical scenarios, such as the p process. Their direct measurement is key for nucleosynthesis model predictions, but is typically hampered by very low cross sections and the lack of intense radioactive ion beams. In this contribution, a novel, powerful method will be presented, which aims at overcoming these limitations: we used decelerated cooled beams in the ESR storage ring at GSI to measure the 124Xe(p, g) reaction directly in inverse kinematics. This reaction belongs to the p process flow and serves as a perfect benchmark for this method. The stable 124Xe beam was accelerated in the UNILAC and the SIS18 to high energies of about 100 AMeV, fully stripped and injected into the ESR. The beam was subsequently decelerated and then cooled with the electron cooler: we were thus able to push the beam energy down to the Gamow window while maintaining brilliant energy resolution. For the first time, this enabled a reaction measurement at the astrophysically relevant energies. In the future, this method will allow reaction studies using radioactive ion beams in or close to the Gamow window at low beam intensities and low cross sections. This contribution will describe the technique and first results will be presented. Also, an outlook towards future studies and techniques will be given.

Speaker: Dr Christoph Langer (University of Frankfurt a. M.)

Slides Langer.pdf

103 A new method for the determination of very small Γγ partial widths¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in \renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Giuseppe Cardella (CT)

Slides Cardella.pdf

104 A new analysis technique to measure fusion excitation functions with large beam energy dispersions¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Pierpaolo Figuera (LNS)

Slides Figuera.pptx

10:20 Coffee break

Direct measurements 3¶

105 23Na(p,g)24Mg Cross Section Measurements¶

The reaction 23Na(p,γ)24Mg links the NeNa and MgAl cycles in stellar hydrogen burning. For temperatures up to 100MK, typical for RGB and low and intermediate mass AGB stars, the rate of this reaction is predominantly determined by the non-resonant component of the cross section and possibly by a narrow resonance at E(c.m.)=138keV. An upper limit for the strength of this resonance has been established in [1]. The non-resonant cross section of 23Na(p,γ)24Mg has not been observed in a direct experiment yet (cf. [2]). The uncertainty of these two contributions to the cross section yields large uncertainties in the reaction rate at these temperatures. A combined effort at the Laboratory for underground Nuclear Astrophysics (LUNA) and the University of Notre Dame aims at a cross section determination for this reaction, to constrain the astrophysical reaction rate by improving the knowledge of the resonance strengths and the non-resonant component. Experiments at LUNA benefit from the underground location at the Gran Sasso National Laboratory which allows for the measurement of resonances at low energies with high sensitivity. Measurements at the University of Notre Dame are used to pursue a determination of the non-resonant cross section at higher energies. The experiments performed at both sites will be presented, together with the status of the analysis and first results. [1] Cesaratto et al., Phys. Rev. C 88, 065806 (2013) [2] Hale et al., Phys. Rev. C 70, 045802 (2004)

Speaker: Axel Boeltzig (GSSI)

106 A new investigation of Hoyle state in 12C via the 14N(d,a2) reaction¶

Given as .tex file

Speaker: Dr Daniele Dell'Aquila (Univ. Napoli Federico II and INFN - Napoli, Italy)

Slides DellAquila.pptx

107 New direct measurement of the 10B(p,alpha)7Be reaction with the activation technique¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ %%% %%% Abstract proper starts here. %%% Boron plays an important role in astrophysics and, together with lithium and beryllium, is a probe of stellar structure during the pre-main sequence and main-sequence (MS) phases. Lithium, beryllium and boron are quickly burned through (p, $\alpha$) reactions at temperatures higher than 2.5 MK. In particular, following the time evolution of the relative N(${}^{11}$B)/N(${}^{10}$B) abundance it is possible to trace mixing phenomena in the early phases of stellar evolution [1].\\ In this context, the ${}^{10}$B(p,$\alpha$)${}^7$Be reaction is of particular interest. At Gamow energies, its cross section is dominated by the contribution of the 8.699 MeV state in ${}^{11}$C, corresponding to an s-wave resonance centred at about 10 keV. Recent measurements of the ${}^{10}$B(p,${\alpha }_0$)${}^7$Be reaction with the Trojan Horse Method (THM) [2] have provided the bare-nucleus S-factor in correspondence of the 10 keV resonance, without the needs of extrapolation procedures. In order to normalize the Trojan horse data, direct cross section measurements are still needed.\\ To give a precise normalisation to indirect data, a measurement of the ${}^{10}$B(p,$\alpha$)${}^7$Be cross section was performed at Legnaro National Laboratories (LNL). As a matter of fact, a normalization problem arose in previous works due to discrepancies in the results of different experimental datasets. At LNL the cross section was determined with the activation technique measuring the activated samples at a low-background counting facility. The analysis of that experiment is now complete [3] and a detailed report of the obtained results will be presented in this contribution. \bigskip {\small \noindent [1] L. Lamia et al., Astrophys. J. 811, 99 (2015).\\ \noindent [2] C. Spitaleri et al., Phys. Rev. C 90, 035801 (2014)\\ \noindent [3] A. Caciolli et al. Eur. Phys. J. A (2016) 52, 136\\ %%% %%% End of abstract. %%% \end{document}

Speaker: Dr Rosanna Depalo (Università degli Studi di Padova and INFN Padova)

108 Study of nuclear physics input-parameters via high-resolution γ-ray spectroscopy¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Mr Philipp Scholz (Institut für Kernphysik, Universität zu Köln, Cologne, Germany)

109 The RIB in-flight facility EXOTIC¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} \begin{document} {\small \it Nuclear Physics in Astrophysics 8, NPA8: 18-23 June 2017, Catania, Italy} \vspace{12pt} \thispagestyle{empty} $$\text{Unknown environment 'center'}$$ The facility EXOTIC [1], installed at the INFN-Laboratori Nazionali di Legnaro (LNL), is devoted to the in-flight production of light short-lived Radioactive Ion Beams (RIBs) in the energy range 3-5 MeV/nucleon. RIBs are produced via two-body inverse kinematics reactions induced by high-intensity heavy-ion beams, delivered by the LNL XTU-Tandem accelerator, impinging on light gas targets such as H${}_2$, D${}_2$, ${}^3$He and ${}^4$He. The main characteristics of the facility is a large RIB acceptance of the optics elements and a maximal suppression capability of the unwanted scattered beams. The event-by-event RIB tracking is performed by means of two position sensitive Parallel Plate Avalanche Counters while the detection of reaction charged particles is achieved by means of the EXPADES array, installed in the reaction chamber at the final focal plane of the facility [2]. So far, different RIBs have been delivered at EXOTIC, like ${}^{17}$F, ${}^7$Be, ${}^8$B, ${}^8$Li, ${}^{15}$O, ${}^{10}$C and ${}^{11}$C, while new beams are foreseen in the next future with the aim to investigate nuclear physics and nuclear astrophysics topics. Experiments with the ${}^{17}$F, ${}^7$Be, ${}^8$B, ${}^8$Li impinging on medium- and heavy-mass targets have been performed at Coulomb barrier energies for structure and reaction mechanism studies whereas recently, the ${}^{15}$O and ${}^{11}$C beams have been employed to search for $\alpha$ clustering phenomena in light exotic nuclei [3], using the Thick Target Inverse Kinematic scattering technique [4]. Another appealing opportunity offered by the EXOTIC RIBs is the possibility of measuring the cross section of astrophysically important reactions. For example, the ${}^8$B beam can be employed to have an accurate knowledge of the rate of the ${}^8$B(p,$\gamma$)${}^9$C reaction, important in hot $\mathit{p}\mathit{p}$-chains as it can provide a starting point for an alternative path across the A = 8 mass gap. Among the different processes of stellar nucleosynthesis forming elements heavier than ${}^9$Be, the rapid proton-capture and $\alpha$p processes, occurring in explosive astrophysical environments such as novae, x-ray bursters and type Ia supernovae, are those than can be investigated by using the EXOTIC RIBs. By developing a radioactive ${}^{18}$Ne beam, the ${}^{18}$Ne($\alpha$,p)${}^{21}$Na reaction could be studied at astrophysical energies to provide a link between the Hot CNO cycle and the $\mathit{r}\mathit{p}$-process. Other measurements relevant to astrophysics can be performed such as the ${}^{30}$P(p,$\gamma$)${}^{31}$S with a ${}^{30}$P beam, essential for the production of heavy elements (from Si to Ca) in the explosion of O-Ne novae and in particular to explain the anomalously high ${}^{30}$Si/${}^{28}$Si rate measured in pre-solar grains of possible ONe novae origin. Moreover, experiments based on the Trojan Horse Method (THM) [5] can be done. In particular, the ${}^7$Be(n,$\alpha$)${}^4$He has been investigated at EXOTIC by applying the THM to the quasi-free reaction ${}^2$H(${}^7$Be,$\alpha$${}^4$He)p (see talk of L. Lamia). \bigskip {\small \noindent [1] V.Z.~Maidikov et al., Nucl. Phys. A 746 (2004) 389c; D.~Pierroutsakou et al., Eur. Phys. J. Special Topics 150 (2007) 47 ; F.~Farinon et al., Nucl. Instr. and Meth. B 266 (2008) 4097; M.~Mazzocco et al., Nucl. Instr. and Meth. B 266 (2008) 4665; M.~Mazzocco et al., Nucl. Instr. and Meth. B 317 (2013) 223\\ \noindent [2] D. Pierroutsakou et al., Nucl. Instr. and Meth. A 834 (2016) 46\\ \noindent [3] M. Freer, Rep. Prog. Phys. 70 (2007) 2149\\ \noindent [4] K. Artemov et al., Sov. J. Nucl. Phys. 52 (1990) 408-411\\ \noindent [5] G. Baur, Phys. Lett. B 178 (1986) 135; C. Spitaleri, Phys. of Atom. Nuc. 74, (2011) 1725; R. E. Tribble et al., Rep. Prog. Phys. 77 (2014) 106901\\ %%% %%% End of abstract. %%% \end{document}

Speaker: Concetta Parascandolo (NA)

Slides Parascandolo.pdf

110 Study of the 2H(p,gamma)3He reaction in the Big Bang nucleosynthesis energy range at LUNA¶

Study of the 2H(p,γ)3He reaction in the Big Bang nucleosynthesis energy range at LUNA V. Mossa for the LUNA collaboration Università degli Studi di Bari and INFN, sezione di Bari Contact email: viviana.mossa@ba.infn.it The Big Bang Nucleosynthesis (BBN) describes the production of light nuclides in the first minutes of cosmic time. It started with deuterium accumulation when the Universe was cold enough to allow 2H nuclei to be survived to photo-disintegration. A primordial deuterium abundance evaluation D/H = (2.65 ± 0.07)10^−5 [1] is obtained by merging BBN calculations and CMB analysis obtained by the Planck collaboration. This value is in tension with the astronomical observations on metal-poor damped Lyman alpha systems, according to which D/H = (2.547 ± 0.033)10−5 [2]. The main source of uncertainty on standard BBN prediction of deuterium abundance is actually due to the radiative capture process 2H(p,γ)3He converting deuterium into helium, because of the poor knowledge of its S-factor at BBN energies. A measurement of this reaction cross section is thus desirable with a 3% accuracy in the energy range 10keV < Ecm < 300keV [1]. Furthermore a precise measurement of the 2H(p,γ)3He reaction cross section is crucial for testing ab-initio calculations in theoretical nuclear physics [3]. The measurement of the 2H(p,γ)3He cross section is ongoing at the Laboratory for Under- ground Nuclear Astrophysics (LUNA) taking advantage of the low background of the underground Gran Sasso Laboratories and of the experience accumulated in more than twenty years of scientific activity on precision measurements. The experiment consists of two main phases characterized by two different setups. The former provides for a windowless gas target filled with deuterium together with a 4π BGO detector. This high efficiency detector has been used for investigating the energy range between 30 keV and 260 keV, finding a continuation of the previous results obtained by the LUNA collaboration in [6], where the 2H(p,γ)3He cross section was studied in the Solar Gamow peak (2.5keV < Ecm < 22keV ). The latter phase, instead, will cover the medium-high energies (70keV < Ecm < 260keV ) using a High Purity Germanium detector (HPGe). The HPGe high resolution allows the differential cross section of the reaction to be evaluated by using the peak shape analysis. The cross section preliminary results will be shown. [1] E. Di Valentino et al., Phys. Rev. D 90 (2014) 023543; [2] R. Cooke at al., Astrophys. J. 830, 2 (2016) 148; [3] L.E. Marcucci et al., Phys. Rev. Lett. 116 (2016) 10250; [4] H. Costatini et al., Rep. Prog. Phys. 72 (2009) 086301; [5] C. Broggini et al., Ann. Rev. Nucl. Part. Sci. 60 (2010) 53; [6] C. Casella et al., Nucl. Phys.,A 706 (2002) 203.

Speaker: Viviana Mossa (Università degli Studi di Bari and INFN, sezione di Bari)

Slides Mossa.pdf

111 3He(α,γ)7Be cross section at high energies¶

% % Nuclear Physics in Astrophysics 8 template for abstract % % Format: LaTeX2e. % % Rename this file to name.tex, where `name' is the family name % of the first author, and edit it to produce your abstract. % \documentstyle[11pt]{article} % % PAGE LAYOUT: % \textheight=9.9in \textwidth=6.3in \voffset -0.85in \hoffset -0.35in \topmargin 0.305in \oddsidemargin +0.35in \evensidemargin -0.35in %\renewcommand{\rmdefault}{ptm} % to use Times font \long\def\TITLE#1{{\Large{\bf#1}}}\long\def\AUTHORS#1{ #1\\[3mm]} \long\def\AFFILIATION#1#2{$\text{You can't use 'macro parameter character \#' in math mode}$ #2\\} $$\text{Unknown environment 'document'}$$

Speaker: Dr Tamás Szücs (MTA Atomki)

Slides Szucs.pdf

Closing remarks¶

13:20 Lunch