Seminario INFN/DIFI di fenomenologia delle particelle elementari – Dr. Ezra Lesser (UC Berkeley)
In recent years, jet and jet substructure observables have been used at the LHC as instruments to search for new physics as well as to test perturbative and probe non-perturbative processes in QCD. Some observables are infrared and collinear (IRC) safe and thus easily comparable to first-principles calculations, while others offer direct insight into specific physical phenomena such as the quark-gluon plasma (QGP) formed in heavy-ion collisions. The high-precision capability of the ALICE tracking system allows a unique opportunity at LHC energies to measure tracks with low $p_text{T}$, permitting both accessibility to the softer components inside jets as well as measurement of jets with altogether lower pT. This allows ALICE a rare view into QCD and QGP dynamics at pT < 100 GeV/c. We review several recent jet measurements in ALICE using both pp and Pb-Pb collisions at 5.02 TeV and discuss the results.
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Per partecipare in presenza, prenotarsi seguendo il link
https://docs.google.com/document/d/1uaw5DHG0VykTHraDiAqYjbLFXsrOIXaftj_n04sj4PE/edit?usp=sharing
oppure per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
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Seminario di Fisica Teorica INFN/DIFI – Dr. Holmfridur Hannesdottir (Institute for Advanced Studies – Princeton)
The S-matrix is a fundamental object in quantum field theory, relating theoretical predictions to data from collider experiments. However, in theories with massless particles when interactions between single-particle states prevail at asymptotic times, the S-matrix is infrared (IR) divergent in perturbation theory. In this talk, we explore three solutions to the IR divergence problem: i) summing over initial and final states to obtain a finite cross section, ii) modifying the S-operator, and iii) using coherent states as scattering states. In particular, we exploit the universality of asymptotic evolution to define a modified S-operator in theories with massless particles. The resulting S-matrix can be interpreted as Wilson coefficients in Soft-collinear effective theory, as remainder functions in N=4 super Yang-Mills theory, or as coherent states. Examining its analytic structure thus provides a new probe of familiar objects from scattering calculations.
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Per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
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Seminario di Fenomenologia delle Particelle Elementari INFN/DIFI – Dr. Enrico Nardi (INFN Laboratori Nazionali di Frascati)
Certain anomalies observed in the angular correlation spectra of
electron/positron pairs produced in nuclear transitions of 8Be, 4He
and 12C can be interpreted as the emission of a bosonic particle with
a mass of 17 MeV, that promptly decays into e+e−. I review the current
status of these anomalies, and some theoretical interpretation for the
hypothetical new particle. I will also describe the prospects for
validating or disproving the X17 hypothesis by means of a particle
physics experiment.
Per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
Consiglio di Sezione
Seminario di Fenomenologia INFN/DIFI – Prof . Umberto De Sanctis (Roma Tor Vergata)
The ATLAS experiment is one of the four experiments collecting data from proton-proton collision produced by the Large Hadron Collider (LHC) at CERN in Geneva. From 2010 to 2018, ATLAS collected more than 150 fb-1 of data in the Run 1 and Run 2 campaigns. In this talk I will summarise the main results obtained during this period by the ATLAS experiment in the flavour physics domain highlighting the strategies to analyse the huge amount of data available and the physics channels where ATLAS can produce competitive results in comparison with other experiments.
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Per partecipare in presenza, prenotarsi seguendo il link
https://docs.google.com/document/d/1uaw5DHG0VykTHraDiAqYjbLFXsrOIXaftj_n04sj4PE/edit?usp=sharing
oppure per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
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Consiglio di Sezione
Seminario di Fenomenologia INFN/DIFI – Mika Vesterinen (Warwick University)
Global fits to precision electroweak data are sensitive to physics beyond the Standard Model but this sensitivity is currently limited by the precision with which the W mass has been directly measured. The most precise measurements of the W mass have been at hadron collider experiments using the kinematic distributions in leptonic W decays. I present the first measurement of the W mass with the LHCb experiment, which is a single-arm small-angle spectrometer experiment at the LHC. I will start with an introduction to the standard model and the precision electroweak observables before describing the challenges in measuring the W mass and the solutions used in LHCb’s measurement. This measurement is based on a subset of the existing LHCb data and I will present an outlook for a more precise measurement with the full dataset, and future combinations with the other LHC experiments.
Per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
Seminario pheno/astro INFN/DIFI – Dr. Simone Iovenitti (INAF)
ASTRI is an Italian project for the study of Very High-Energy astrophysical phenomena up to 300 TeV and beyond. After the success of the first prototype instrument located in Italy, ASTRI-Horn, the project is entering the realization phase of the MiniArray: 9 identical Cherenkov telescopes working in stereoscopic mode to be installed in Tenerife, Canary Islands. The ASTRI telescopes present a dual-mirror Schwarzschild-Couder optical configuration (never adopted before in gamma-ray astronomy) and a Cherenkov camera based on fast SiPM sensors, able to image the nanosecond atmospheric flashes produced by energetic cosmic photons. Unfortunately, such devices are almost blind to the steady flux of stars in the field of view and consequently the calibration of their pointing represents a technological challenge, also because the compactness of the structure prevents from installing auxiliary monitoring camera sharing the same optical system of the telescope. However, exploiting the so-called Variance method (a statistical algorithm implemented in the ASTRI electronics) the star signal can be successfully recovered by ASTRI (down to ~ 7 mag), offering the potentiality to image the night sky background and meet the demanding pointing requirement (few arc-sec) despite the coarse pixel size of the camera (11 arc-min). To this end, dedicated astrometry techniques have been developed on purpose. Their validation with data from ASTRI-Horn revealed the presence of unexpected systematic errors, demonstrating the importance of such analysis. At present, similar routines for the astrometric calibration of the pointing are being developed to be implemented in the MiniArray, enhancing the accuracy of the whole system.
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Per partecipare in presenza, prenotarsi seguendo il link
https://docs.google.com/document/d/1uaw5DHG0VykTHraDiAqYjbLFXsrOIXaftj_n04sj4PE/edit?usp=sharing
oppure per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
Seminario di Fenomenologia – Dr. Diogo Boito (Universidade de Sao Paulo/University of Vienna)
The theoretical precision of many crucial observables in the
Standard Model is nowadays limited by our knowledge of QCD parameters.
Determining the strong coupling and quark masses with smaller uncertainties is
therefore a fundamental task in order to match the reduced errors
that are expected from present and future experiments.
Extracting the QCD parameters is not a straightforward task, since
they are not physical observables: theory input is as important as experimental data. I will
discuss recent developments in the precise determination of the strong coupling
around the tau mass scale, which represents one of the most stringent
tests of asymptotic freedom. I will discuss a viable solution to a
long-standing problem related to the renormalization group improvement
of the perturbative series, the interplay between perturbative and
non-perturbative contributions, and the role of recent experimental
data.
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Per partecipare in presenza, prenotarsi seguendo il link
https://docs.google.com/document/d/1uaw5DHG0VykTHraDiAqYjbLFXsrOIXaftj_n04sj4PE/edit?usp=sharing
oppure per partecipare su Zoom, collegarsi al meeting
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271
Seminario di didattica – Claudia De Grandi (Utah University)
Claudia de Grandi ha studiato a Milano, e si è formata durante il suo PhD e post-doc, all’università di Boston e poi a Yale, come fisica teorica della materia condensata. Dal 2018, de Grandi è Assistant Professor (Lecturer) of Educational Practice all’Università dello Utah, US. Da diversi anni i suoi interessi principali di ricerca riguardano soprattutto la didattica della fisica. Il seminario è rivolto a tutti i docenti dei nostri corsi di laurea, e sarà una importante occasione di formazione: spero partecipiate numerosi!
Abstract:
Educational research shows correlation between students’ learning gains and formative assessment. Active learning techniques in STEM have been proven to produce better learning outcomes. I will argue for the need to shift from a traditional instructor-centered approach to an interactive student-centered course structure which offers continuous opportunities for formative feedback. I will provide concrete examples of assessment approaches in STEM that build collaboration among students and instructors, increase student self-efficacy, and hence help students achieve content mastery.
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Zoom link:
https://utah.zoom.us/j/94051338743
Passcode: 17marzo