Seminario di Fenomenologia – Dr Lorenzo Bianchini (INFN Sezione di Pisa)
The mass of the W boson offers a unique opportunity for testing the electroweak sector to high precision. At present, the Standard Model of strong and electroweak interactions yields an indirect determination of the W boson mass which is more precise than the direct measurement. The gap between theory and experiment, made even more intriguing by a slight tension between the two, motivates the continuation of the experimental program. Unfortunately, at the LHC, this program has hit the wall of systematic uncertainty, mostly related to our imperfect description of hadron collisions. ASYMOW is an ERC-funded project which proposes a new approach, agnostic with respect to the microscopic picture of W boson production, to circumvent the limiting systematic uncertainties. The intrinsic model-independence of the method, joined with its robustness towards the harsh environmental conditions of proton-proton collisions, will allow for a full exploitation of the unprecedented data set collected by the CMS experiment at the LHC. By leveraging this power, a big step ahead on the experimental side seems possible. This project comes with great experimental, theoretical, and computational challenges. Its successful completion would set a milestone in precision at hadron colliders, with far-reaching implications.
Per partecipare: gruppo Teams Università di Genova numero 1npbr0h (se si possiede un account Teams Unige, si può accedere con il codice.
Se invece si possiede solo un account Teams INFN, scrivere a simone.marzani@ge.infn.it per essere aggiunti come ospiti).
Colloquium – Dr.ssa Elena Santopinto
Quarks that combine in much more complex ways than scientists expected can have repercussions in many fields, not only in particle physics, but in astronomy, from neutron stars to dark matter. The recent observation by LHCb of a meson made of four charm quarks (T_cccc) and of three pentaquark states (P_c^+) has consecrated the subject of exotics as a hot topic. New experiments at LHC and Belle plan to shed light on this unexpected behavior
and try to understand the strong force at long distance. In this talk, some of the main experimental findings and theoretical predictions given before the experimental discoveries, regarding fully charm tetraquarks and pentaquarks, will be presented and discussed.
Per partecipare: gruppo Teams Università di Genova numero 1npbr0h (se si possiede un account Teams Unige, si può accedere con il codice. Se invece si possiede solo un account Teams INFN, scrivere a simone.marzani@ge.infn.it per essere aggiunti come ospiti).
Seminario di Fenomenologia – Dr. Alessandro Guida (Genova Univ. and DESY Hamburg)
High energy physics experiments are performed at the Large Hadron Collider at CERN colliding bunches of protons at energies up to 13 TeV. The ATLAS experiment, with its multipurpose detector, studies the products of these colli- sions and compares the experimental measurements with the predictions of the Standard Model. This talk presents the study of the process Z/γ∗ → μμ at low invariant mass of the di-muon pair, in the region between 7 GeV and 60 GeV, below the Z boson resonance mass peak (mZ = 91.2 GeV). The single and double differential cross sections of the process are measured in 13 TeV proton-proton collisions at the LHC, using the ATLAS detector. The measurement explores an extreme region of the phase space and is sensitive to resummation results in the theoretical prediction. The analysis exploits the good resolution of the ATLAS detector in reconstructing low momentum muons. The main difficulties come instead from the high background component that enters in the event selection, the triggering of events and the modelling of some key physical quantities.The main features of the analysis, the studies done to overcome the main challenges, as well as the first results and comparison to theory predictions are presented in the talk.
Per partecipare: gruppo Teams Università di Genova numero 1npbr0h (se si possiede un account Teams Unige, si può accedere con il codice. Se invece si possiede solo un account Teams INFN, scrivere a simone.marzani@ge.infn.it per essere aggiunti come ospiti).
Seminario Colloquium – Dr. Marco Incagli (INFN Pisa)
The recently published result by the Fermilab Muon g-2 experiment on the muon anomaly a_mu, based on the first dataset collected in Spring 2018, confirms the discrepancy of the observed value from the currently Standard Model prediction, reaching 4.2 standard deviations. The data already collected, and currently under analysis, will half the current uncertainty, while the full dataset, including the run programmed to be concluded in June 2022, will reduce the error by a factor of 4, thus potentially allow for a discovery of new physics beyond the Standard Model.
After a historical introduction, the experiment will be reviewed, discussing the critical issues of the first set of data and how they have been addressed in view of the high statistics Runs.
Recent theoretical developments will be also presented.
Per partecipare: gruppo Teams Università di Genova numero 1npbr0h (se si possiede un account Teams Unige, si può accedere con il codice. Se invece si possiede solo un account Teams INFN, scrivere a simone.marzani@ge.infn.it per essere aggiunti come ospiti).
Seminario di Fisica Teorica – Dr. Daniel Brattan (Genova Univ.)
I will review our recent works concerning a large class of systems with spontaneous, pseudo-spontaneous and explicitly broken translation invariance in the presence of an external magnetic field. In particular I will show how the Ward identities constrain the transport coefficients of hydrodynamics. We will discuss a holographic realisation of these analytic results and place them in the wider context of the quasi-hydrodynamic programme.
Per partecipare: gruppo Teams Università di Genova numero 1npbr0h (se si possiede un account Teams Unige, si può accedere con il codice. Se invece si possiede solo un account Teams INFN, scrivere a simone.marzani@ge.infn.it per essere aggiunti come ospiti).
Consiglio di Sezione – Consuntivi
Ordine del Giorno:
1) Comunicazioni del Direttore dal Consiglio Direttivo
2) Presentazioni dei consuntivi da parte dei Coordinatori
3) Politica pubblicazioni Open Access (intervento di Andrea Chincarini)
2) Varie ed eventuali
Seminario di Fisica Teorica – Dr. Stefano Giusto (Genova Univ.)
I will review recent results on the computation of correlators in the strongly coupled CFT holographically dual to AdS$_3times S^3$ in the limit of large central charge. The derivation of the correlators bypasses the standard technique based on Witten diagrams and uses the geometry dual to coherent multi-particle states. I will also discuss various properties of the correlators: their Regge limit, their OPE analysis and a surprising 6D conformal symmetry that constrains the correlators.
Per partecipare: gruppo Teams Università di Genova numero 1npbr0h (se si possiede un account Teams Unige, si può accedere con il codice. Se invece si possiede solo un account Teams INFN, scrivere a simone.marzani@ge.infn.it per essere aggiunti come ospiti).
Seminario di Fisica Teorica – Dr. Ioannis Mattheakakis (Wurzburg Univ.)
In recent years a lot of interest has been directed towards realizing strongly-coupled electronic fluids. This interest is partly because a stronger coupling enables the transition to the hydrodynamic regime and partly because of the novel transport phenomena such a fluid promises. Strongly-coupled fluids are also a natural and fertile ground for testing and refining our understanding of AdS/CFT and holography in general. In this talk, I will first show that Kagome materials with a relativistic spectrum are a compelling platform for realizing strongly-coupled fluids. Then, I will employ holography to estimate their ratio of shear viscosity to entropy density. With that estimate at hand, I will finally argue that strongly-coupled Kagome fluids put for the first time non-linear hydrodynamic phenomena such as turbulence within experimental reach.
Per partecipare: collegarsi al meeting Zoom
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
Seminario di Fenomenologia – Dr. Riccardo Torre (INFN Sezione di Genova)
The LHC and HL-LHC physics program is not even half-way and the absence of new physics signals claims for a strategy to build what will be the HL-LHC legacy in terms of new physics searches. The lack of signals of light new physics have put the model independent Effective Field Theory (EFT) approach forefront in looking for deviations of observables from their Standard Model predictions. There are mainly three directions in which the EFT program is meeting precision and is expanding its potentials: on-shell Higgs measurements, low energy observables (flavor), and high energy precision. These three are generally described by different sectors of the Standard Model EFT (SMEFT): schematically, Higgs on-shell observables correspond to Higher Dimensional Operators (HDO) involving additional Higgs fields, flavor observables to SMEFT operators at scales well below the EW gauge boson masses (both flavor violating and flavor conserving), while high energy observables correspond to similar operators at scales much above the EW gauge boson masses. Obviously, exploiting the interplay of the three, and combining their information, becomes crucial in building an overall picture.
In this talk I will introduce the three directions highlighted above and then focus on the third: high energy precision. I will introduce the concept of BSM measurements (to be contrasted with SM measurements and BSM searches) and try to motivate why, in my view, this will be the crucial step needed to build what could become the HL-LHC legacy.
Per partecipare: collegarsi al meeting Zoom
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
Seminario di Fisica Teorica – Paolo Meda (Università di Genova e INFN di Genova)
A first approximation to describe the interplay between quantum matter and gravity is given by the quantum field on curved spacetimes and the semiclassical gravity, in which the backreaction of a quantum matter field propagating over a fixed spacetime geometry can be analyzed by using the so-called semiclassical Einstein equation. In this framework, the evaporation of four-dimensional spherically symmetric black holes can be explained by the appearance of an ingoing negative energy flux at the apparent horizon, which induces a negative variation of the black hole mass. I will show that this flux can be sourced by the trace anomaly of the quantum stress-energy tensor in case of a massless conformally-coupled scalar field once a certain averaged energy condition is assumed outside the horizon. As an example, I will compute the negative flux and the rate of evaporation in the Vaidya spacetime, which describes the exterior geometry of a null radiating star.
Per partecipare: collegarsi al meeting Zoom
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271