Seminari 2018

1 Jan 2018, 08:00 → 31 Dec 2018, 18:00 Europe/Rome

Dipartimento di Fisica e Scienze della Terra e sezione INFN di Ferrara

Stefania Vecchi (FE)

Lista dei seminari di Fisica del Dipartimento di Fisica e Scienze della Terra e della sezione INFN di Ferrara

Friday 12 January

1 Diagnostiche per immagini di opere d'arte e reperti archeologici

Verranno illustrate le più usate tecniche fisiche che producono immagini dell’opera d’arte o del reperto archeologico. Immagini che evidenziano dettagli utili per la conservazione o per lo studio del manufatto. Di ogni tecnica verranno mostrati i più significativi e spesso inediti risultati ottenuti su opere provenienti dai Musei Civici di Ferrara, Bondeno, Lido di Spina, dalla Pinacoteca Nazionale e dal Museo Archeologico di Ferrara.

Speaker: Ferruccio Petrucci (Universita di Ferrara)

Friday 19 January

2 Tecniche per la radiografia di beni culturali

Verranno illustrati le motivazioni e i risultati dell’applicazione della radiografia X ai dipinti, con esempi di dipinti rinascimentali e moderni.

Speaker: Ferruccio Petrucci (Universita di Ferrara)

Friday 26 January

3 I colori dei dipinti antichi: come li analizziamo senza prelievi

Le misure di Fluorescenza X con strumenti portatili hanno inaugurato una nuova stagione nello studio delle tecniche artistiche: ricostruire la tavolozza degli artisti del passato senza eseguire prelievi sulle opere permette di raccogliere informazioni sui materiali e sul loro impiego come un tempo era possibile solo con l’analisi chimica. Ma con una maggiore, potenzialmente illimitata statistica. I risultati ottenuti su dipinti dal Rinascimento al Cubismo illustreranno i principi di questa applicazione della Spettroscopia X.

Speaker: Ferruccio Petrucci (Universita di Ferrara)

Wednesday 7 February

4 The lower limit on the mass of Fermionic Warm Dark Matter from the smallest Dwarf Spheroidal Galaxies

The nature of dark matter still eludes our comprehension and a number of hints may derive from the zoology of the observed dark matter profiles. I reconsider the lower bound on the mass of a fermionic dark matter (DM) candidate, typically sterile neutrinos, that results from the existence of known small Dwarf Spheroidal galaxies, when their DM halo is approaching the limit of quantum degeneration. By relaxing the common assumption that the DM halo scale radius is similar to the scale radius of the luminous stellar component, and by marginalizing on the effects of the unknown stellar velocity dispersion anisotropy, we prove that present observations lead to rather weak constraints on the DM mass, that could be as low as tens of eV. In this scenario, the DM halos would be quite sizable. At the same time, we show that the strongest bound stems instead from the requirement that the time of orbital decay of these Galactic satellites due to dynamical friction in the hosting Milky Way DM halo is long at least as their lifetime. The smallest and nearest Dwarf galaxies lead to a final lower bound of m>100 eV, still quite weaker than previous estimates, but robust and independent from the DM formation and decoupling mechanism.

Speaker: Fabrizio Nesti (Universita' dell'Aquila)

Thursday 15 February

5 Symmetry: What can Philosophy learn from Physics?

seminario di storia e filosofia della scienza abstract: This contribution explores the meaning of symmetry in mathematics and physics in order to highlight the role that this concept can play in philosophy of physics and for philosophy in general. After introducing different notions of symmetry I shall analyse the functions that scientists attribute to symmetry in different contexts, such as General Relativity and neutrino physics. Then I shall show which aspects of our scientific research on symmetry had an impact on philosophy of physics and offer a perspective of philosophy of science in practice to open the path to a wider reflection on symmetries in physics and philosophy. This move in turn will disclose future perspectives on the ways in which we can modify philosophy starting from the achievements obtained by scientific theories.

Speaker: Silvia De Bianchi (Department of Philosophy & Centre for the History of Science (CEHIC), Autonomous University of Barcelona)

Tuesday 20 March

6 High energy neutrinos from the galaxy

I will discuss the expectations for high energy neutrino and gamma flux produced in the interaction of CR with the gas contained in the galactic disk. I will consider the implications of the recent results of IceCube neutrino telescope and of the HESS gamma ray telescope.

Speaker: Villante Francesco (Universita' dell'Aquila)

Thursday 22 March

7 Decay law: non-exponential features and connection to time dilatation

The exponential decay law of quantum unstable particles is not exact: deviations at short and long times occur. We review the theoretical origin of these deviations as well as their experimental proofs. Then, we study the theory of the decay law for a moving unstable particle and show some unexpected features of the latter.

Speaker: Giacosa Francesco (Universita' di Kielce (Polonia))

Thursday 19 April

8 Photon-photon and hadron-photon colliders based on Compton Sources and FELs for fundamental research

Free Electron Lasers and Compton Sources based on Inverse Compton Scattering (I.C.S.) are nowadays the most advanced generators of high brilliance photon beams in the keV and MeV, respectively, photon energy ranges. Although developed during the last 2 decades mainly for enabling applied research in several domains, spanning from biological, medical, cultural heritage, to matter science and nuclear photonics, these X/ g photon machines may become the basic and crucial components of more complex systems for new discoveries in fundamental areas of high energy particle physics. We will illustrate various scenarios of combining secondary and tertiary beams of photons, hadrons and muons, based on highly asymmetric boosted colliders, aiming at enabling experiments on never observed phenomena like eleastic photon scattering (light interacting with itself, "a’ la lightsaber, the Jedi’s sword") and matter creation from light.

Speaker: Luca Serafini (INFN Milano)

Wednesday 2 May

9 Dark Matter indirect detection: status as of spring 2018

Dark Matter constitutes more that 80% of the total amount of matter in the Universe, yet almost nothing is known about its nature. A powerful investigation technique is that of searching for the products of annihilations of Dark Matter particles in the galactic halo, on top of the ordinary cosmic rays. Recent data from satellite, balloon and ground based experiments have reported unexpected excesses in the measured fluxes of charged cosmic rays and of gamma rays, which have been interpreted as a possible first direct evidence for Dark Matter. However, confirmations are not easy. Which DM models and candidates can explain the anomalies and what do they imply for future searches? What are the constraints from other measurements and from cosmology? And what is in store for the near future in this field?

Speaker: Marco Cirelli (Laboratoire de Physique The ́orique et Hautes Energies (LPTHE), CNRS & Sorbonne Universite ́)

Thursday 3 May

10 I colori dei dipinti antichi: come li analizziamo senza prelievi

This seminar shall be devoted to the description of the K-edge method for elemental imaging, i.e. mapping a chemical element in a painting through the digital elaboration of X-ray images.

Speaker: Ferruccio Petrucci (Universita' di Ferrara e INFN)

Tuesday 15 May

11 The axion as a CDM candidate and as a cosmological probe

The axion is a hypothetical particle arising from the solution, proposed by Peccei and Quinn in 1977, to the long-lasting “strong-CP” problem within the QCD sector of the Standard Model of particle physics. In this talk, I will discuss three main topics. First, I will give an overview of axion physics, including current and planned experiments. Second, I will discuss the axion as the Cold Dark Matter candidate and as a probe of the Early Universe. Third, I will illustrate both the nuisance and the detection opportunities brought in by the possibility that axions clump into “axion stars”.

Speaker: Luca Visinelli (Oskar Klein Centre, Stockholm University)

Friday 18 May

12 Recent results from the NA62 Experiment on the K+ → π+ ν ν̄ decay study.

The NA62 Experiment, installed in the CERN North Area, studies the physics of the K+ meson, exploiting a 400 GeV proton beam from the SPS accelerator colliding with a fixed beryllium target. Its main purpose is to carry out a precision test of the Standard Model, measuring the branching ratio of the ultra-rare dacay K+ → π+ ν ν̄ , whose most recent value predicted by the theory is BR(K+ → π+ ν ν̄) = (0.84 ± 0.10) · 10−10 , where the main contribution on the theoretical uncertainty is due to the knowledge of the CKM matrix elements. The NA62 goal is to perform this measurement with a 10% precision, in order to strictly test the Standard Model and try to figure out New Physics evidence. After the full detector commissioning in 2016, NA62 collected data in 2016 and 2017, and a new run is going on. until the november 2018. The full 2016 data sample has been analyzed: the preliminary results and the future perspectives will be presented.

Speaker: Francesco Brizioli (Universita' e INFN di Perugia)

Wednesday 23 May

13 Cosmological evolution in R^2 modified gravity

Evolution of the universe in R+R^2 theory is considered from inflation induced by the R^2 term to the moment of restoration of the standard FRW cosmology. Exact analytic and numericail solutions in the post-inflationary period are found. Effects of particle production by the oscillating curvature is taken into account. The impact of the deviation from the standard expansion regime on the freezing of species and on PBH production is discussed.

Speaker: Sasha Dolgov (Università di Ferrara)

Wednesday 6 June

14 Datazione con Radiocarbonio di dipinti del Novecento

La datazione con radiocarbonio è da quasi 70 anni la tecnica più nota e seguita per datare per manufatti artistici e reperti archeologici degli ultimi 60 000 anni, pur avendo incontrato in molte sue applicazioni grandi difficoltà e suscitato forti polemiche. Oltre a presentare i criteri scientifici alla base della datazione, si esporranno le motivazioni che oggi ne consentono l’applicazione a dipinti eseguiti dal 1955 in poi.

Speaker: Ferruccio Petrucci (Universita di Ferrara e INFN)

Thursday 14 June

15 Analisi scientifiche: il caso Sindone

The Shroud of Turin is not only an archaeological and historical remain, but also a relic of worship. Every investigation has caused controversy, even even calling into question the reliability of scientific techniques. Starting from the historical presentation, the description of the scientific analyses will be given, and how our knowledge of this unique finding is today evolved.

Speaker: Ferrucci Petrucci (Università di Ferrara e INFN)

Tuesday 25 September

16 Follow-up strategies of large GW sky-localization by electromagnetic telescopes and the early alert to electromagnetic followers.

A wide range of outcomes is expected from binary neutron star (BNS) mergers, based on the total mass of the binary system, the mass ratio and the neutron star equation of state. Detection of optical and radio afterglow are sensitive to the area of the localization, observing constrains and the telescope. Searching these large sky regions spanning a few tens to hundreds of square degrees is a formidable challenge for most ground-based telescopes. The speaker will talk about various methods of fast follow-up strategies to find the counterpart of the gravitational wave source, notably in x-ray, optical and radio. The first part of the talk is about the algorithms for better scheduling of such follow-up observations in order to maximize the detection probability of the optical and radio counterpart (afterglow), based on the all–sky probability distribution of the source position. The algorithms incorporate the realistic observing constraints and include galaxy catalog to improve the search. The latter part of the talk demonstrate the importance of early trigger and alert of the BNS merger in aLIGO sensitivity to observe the prompt emissions (and pre-merger emissions) from the BNS coalescence. He will discuss the challenges to produce an early alert and possible solutions to those. The work accounts the background rate and the computation time to generate the alert. We use PyCBC to search for the signal and BAYESTAR to localize the source on the sky.

Speaker: Javed Rana (Inter-University Centre for Astronomy and Astrophysics, Pune, India.)

Wednesday 7 November

17 Silk and Hairs: a biomimetic approach

This seminary will present the main topics concerning the biomimetic approach applied to octopuses and spiders. In particular, the role of spider hairs in adhesion and hydrophobicity will be explained pointing out their hierarchical structure. This hierarchy allows spiders to optimize the adhesion both in presence of high and low humidity rates. Moreover, it has a key role in hydrophobicity of this animals and in their sensing capabilities. The hairs of the spiders, thus, could be crucial natural structures able to inspire the design of artificial structures with superior properties. Furthermore, the hairs of spiders are able to detect air flows with a extreme sensitivity. The seminar will focus on the models used to explain the motion of the hairs and also used to design artificial sensors. As an independent confirmation of the model, octopus hairs are also crucial in the adhesion of octopus suckers and this happens very similarly to the adhesion of spiders. Finally, the role of spider silk in technology will be explained focusing on its possible applications in medicine, engineering and food industry.

Speaker: Gabriele Greco (Department of Civil, Environmental and Mechanical Engineering, University of Trento)

Tuesday 27 November

18 Constraining the neutron star EOS using GW170817

The first detection of gravitational waves from binary neutron star merger event GW170817 is providing important new constraints on the nuclear equation of state at high density. The tidal deformability bound of GW170817 combined with the observed 2M_sun neutron star poses serious challenge to theoretical formulations of realistic equation of state. We analyze a fully comprehensive set of relativistic nuclear mean-field (RMF) theories by confronting with the observational bounds and the measured neutron-skin thickness. We find only 3 (out of 269) RMF models are consistent with these bounds. Two possible indications are proposed: Circumstantial evidence of hadron-quark phase transition inside the star and new parametrizations that are consistent with ground state properties of finite nuclei and observational bounds. Based on extensive analysis of these sets, we also obtain an upper limit for the radius of a 1.4M_sun neutron star as R(1.4M_sun) < 12.9 km.

Speaker: Rana Nandi (Tata Institute of Fundamental Research, Colaba Mumbai, INDIA)