7th Rome Joint Workshop: Current topics in Particle Physics

18 Dec 2018, 08:00 → 20 Dec 2018, 19:00 Europe/Rome

<span style="background-color:#ffff00;">High Energy Building, Seminar Room (1st floor)</span> (<br />Laboratori Nazionali di Frascati)

Barbara Mele (ROMA1), Enrico Nardi (LNF), Gennaro Corcella (LNF), Roberto Franceschini (ROMA3)

Aim of the workshop:

The workshop will deal with several open issues in high-energy physics in the era of the LHC. We shall discuss topics ranging from Standard Model (QCD) phenomenology to fashionable new physics models, such as supersymmetry or Dark Matter theories. Most speakers will be young fellows working or collaborating with the phenomenology groups in the Rome area. All talks will be presented in a pedagogical way and plenty of time will be scheduled to allow discussion among participants.

Scientific Program and Speakers:

Robert Ziegler (CERN)
"DM photon effective operators"

Matthew Kirk  (INFN Roma)
"Hints of new physics in flavour anomalies"

Paolo Panci (CERN)
"Bounds on Dark Matter Annihilations from 21-cm data"

 Fred Bjorkeroth  (INFN LNF)
"Peccei-Quinn Symmetry as a Flavor Symmetry"

Luca Marzola (NICPB, Tallin)
"The dark side of neutron stars"

Filippo Sala (DESY)   
"Beyond WIMPs at neutrino experiments: heavy and light Dark Matter"

Federica Giacchino  (INFN LNF)
"A new Simplified Dark Matter Model: the Vector-like Portal"

Marco Bonvini (INFN Roma)
''New insights on the proton's structure''

Ramona Groeber (HUMBOLDT U., Berlin)
"Future probes of the Higgs boson"

Pier Paolo Giardino (IFT Madrid)
"Variation of alpha from a DM force"

Luca Vecchi  (Lausanne)
"Model Building and Un-Naturalness"

Ennio Salvioni   (Munich Tech. U.)
"Composite PNGB Dark Matter"

 

Some funds are available to support participation of INFN  researchers, postdocs and associates.
To inquire please contact: enrico.nardi@lnf.infn.it 

 

Tuesday, 18 December

1 Hints of new physics in flavour anomalies (and what meson mixing and lifetimes can tell us)

Over the last 5 years, there have been increasingly strong hints of something amiss in flavour physics. Starting with a small anomaly in a rare decay mode of B mesons, the current status amounts to a coherent set of discrepancies involving the non universality of decays to different flavour leptons - with a combined significance of around 5 sigma. I will review the history of these flavour anomalies, and what we mean by a coherent EFT explanation. I will introduce meson mixing and lifetimes and how they are calculated, and then discuss how possible NP models that explain the anomalies are strongly constrained by these calculations.

Speaker: Matthew Kirk (INFN Roma)

Slides kirk_lnf_jrw.pdf

2 A realistic U(2) Model of Flavor

I will discuss a simple U(2) model of flavor, where all hierarchies in fermion masses and mixings arise from powers of two small parameters. In contrast to previous U(2) models this setup can provide an excellent fit to all SM flavor observables including neutrinos, and one naturally obtains large mixing in the lepton sector from small mixing in the quark sector. The model predicts an upper bound on the neutrino mass scale below current cosmological bounds, and thus is testable in the near future. This model can also be used to address B-anomalies in the context of vector leptoquarks, where the flavor structure of the new couplings are connected to SM flavor hierarchies.

Speaker: Robert Ziegler (CERN)

13:00 Lunch Break

3 Bounds on Dark Matter Annihilations from 21-cm data

In March 2018 the EDGES experiment has reported, for the first time, the discovery of an absorption feature in the 21-cm spectrum at redshift around 17. This measurement, if confirmed, is fundamental because can give us information about the epoch of reionization soon after the formation of first stars and galaxies. This talk is organised in three parts. In the first part I’ll present the EDGES experiment and the procedure the collaboration has used to extract the small 21-cm signal from very large foreground of diffuse galactic synchrotron emission. Then I’ll review the physics of the 21-cm line and the history of the InterGalactic Medium (IGM) properties assuming a LambdaCDM Universe. Finally, I’ll conclude with a simple application of this measurement to set bounds on the Dark Matter (DM) properties. In particular, annihilating DM particles produce significant heating of the IGM erasing the absorption feature measured by EDGES. These limits, derived for the first time in our paper, are very strong and, in some cases, the most stringent in the literature.

Speaker: Dr Paolo Panci (CERN)

Slides Rome_18122018.pdf

15:40 Coffee Break

4 New insights on the proton's structure

I will review the recent progress on the understanding the proton's structure, and specifically the Parton Distribution Functions (PDFs) that describe the longitudinal momentum distributions of its constituents. I will mostly focus on the inclusion of the resummation of classes of logarithms in the theory adopted for their extraction from data. I will also comment on the phenomenological impact at the LHC of these developments.

Speaker: Marco Bonvini (INFN Roma)

Slides bonvini_LNF.pdf

Wednesday, 19 December

5 Future probes of the Higgs boson

After the Higgs boson discovery the task in Higgs physics is now to probe  the Higgs boson as precisely as possible to see if the Higgs sector shows any deviations from the Standard Model. In this talk I will discuss future probes of the Higgs sector. I will mainly focus on Higgs pair production which, among other things, allows to probe the trilinear Higgs self-coupling.

Speaker: Ramona Groeber (Humboldt U. Berlin)

6 Variation of alpha from a DM Force

In this talk I will consider the possibility that the dark matter interacts with the Standard Model (SM) through a feeble long range force $\phi$. This scenario has potentially interesting effects on the SM physics, depending on the radius and on the strength of the interaction. I will review some of these effect, concentrating in particular on the possibility that $\phi$ directly affects the measured value of the fine structure constant.

Speaker: Dr Pier Paolo Giardino (IFT Madrid)

13:00 Lunch Break

7 The dark side of neutron stars

I will try here to convince you that neutron stars can be used as a laboratory to test dark matter candidates that deviate from the standard WIMP scenario. After introducing toy models that lead to the formation of dark structures bounded to neutron stars, I will show how the presence of dark matter affects typical neutron stars observables such as the mass-radius relation, tidal deformability and the gravitational wave spectrum emitted by neutron stars mergers.

Speaker: Luca Marzola (NICPB Tallin)

15:40 Coffee Break

8 Beyond WIMPs at neutrino experiments: heavy and light Dark Matter

I will discuss two novel proposals to probe Dark Matter (DM) with existing and upcoming data. 1. DM lighter than a GeV is unavoidably accelerated by scatterings of cosmic-rays, making it possible to detect it at experiments with large energy thresholds and volumes, like SuperKamiokande and DUNE. I will derive a new limit from public data, that turns out to be the strongest existing one in a wide region of parameter space, and discuss search strategies at current and future neutrino experiments. 2. Cosmic rays constitute our arguably unique direct access to energy domains of 10 TeV and above, and a wealth of data is/will soon be delivered by current/near-future telescopes (ANTARES, IceCube, KM3NeT, but also HESSII, CTA, LHAASO, CALET,...). Heavy DM constitutes therefore an ideal BSM target for these experiments: I will discuss the theory and phenomenology of DM models that evade challenges like the so-called unitarity bound, and propose related searches at such telescopes.

Speaker: Filippo Sala (DESY Hamburg)

Thursday, 20 December

9 A new Simplified Dark Matter Model: the Vector-like Portal

The nature of the Dark Matter is a mystery not yet solved and its identification is a big challenge for model builders and experimentalists. Among the plenthora of possible DM candidates, the Weakly Interactive Massive Particle (WIMP) is the most popular solution. In order to demonstrate that this is the valid explanation to the DM problem, a non-gravitational signal and also a model to interpret a possible DM message are needed. I will present a new Simplified Model, called Vector-like Portal, which connects the hidden and the visible sector through a Vector-like fermion and promotes a real scalar Dark Matter. I will show the main features of model and its important consequences in the phenomenological analysis for all three different DM search strategies, when it is coupled to leptons, light and heavy quarks.

Speaker: Federica Giacchino (INFN LNF)

10 Model-Building and Un-Naturalness

Conventional solutions of the hierarchy problem are severely constrained by direct and indirect searches. All attempts to explain the EW scale naturally require very complicated and seemingly ad-hoc constructions. By accepting some amount of tuning as a fact of Nature, however, these scenarios become very simple and attractive extensions of the SM. I will discuss how un-natural composite Higgs models represent compelling theories for flavor, dark matter, and (most of) the hierarchy problem. I will also comment on novel realizations of baryogenesis within un-natural scenarios.

Speaker: Luca Vecchi (Lausanne)

13:00 Lunch Break

11 Composite pNGB Dark Matter

The dark matter (DM) could emerge along with the Higgs as a composite pseudo-Nambu-Goldstone boson with decay constant f ~ TeV. This type of WIMP is especially interesting because its leading interaction with the Standard Model, the derivative Higgs portal, has the correct annihilation strength for thermal freeze-out if the DM has weak-scale mass, but is negligible in direct detection experiments due to the very small momentum transfer. The explicit shift symmetry breaking required to generate radiatively the DM mass, however, also introduces non-derivative DM interactions. I will discuss the associated phenomenology, focusing on scenarios where the pattern of explicit symmetry breaking naturally suppresses the direct detection cross section beyond the reach of current experiments.

Speaker: Ennio Salvioni (Munich Tech. U.)

Talk_LNF_upload.pdf

15:40 Coffee Break

12 Peccei-Quinn Symmetry as a Flavor Symmetry

There has been recent interest in possible connections between a Peccei-Quinn (PQ) symmetry and quark flavour structures. I describe how a generic generation-dependent U(1) symmetry acting on the quark Yukawa operators can reduce the number of free parameters in the quark sector. The maximal reduction compatible with CP violation yields nine real parameters and one phase, which matches the number of physical observables, implying that such models have no free parameters. This has several interesting consequences: (i) there are only two inequivalent textures, each one giving rise to six different models depending on quark flavour assignments, (ii) the U(1) symmetries that generate these textures all have a QCD anomaly, and hence are PQ symmetries, (iii) the resultant axion has flavour-violating couplings to quarks, which can be probed in meson decays, (iv) in some cases the contributions to the QCD anomaly of two generations cancels out, opening up the possibility that the axion coupling to nucleons is strongly suppressed.

Speaker: Fredrik Bjorkeroth (INFN LNF)