Calendar

Dic
16
Ven
Scattering Amplitudes: Mathematical Methods and Novel Results (Giulio Gambuti, Oxford U.) @ Aula 500 e online
Dic 16@2:00 pm–3:00 pm

Seminario di Fisica Teorica

Scattering amplitudes provide a window on the mathematical structure of Quantum Field Theory and serve as a bridge between theoretical predictions and experimental data. Because of this, their computation is of interest to many different research areas. Although much progress has been made in the last few decades, it remains very hard to compute scattering amplitudes at higher orders in perturbation theory. I will describe modern mathematical methods for the analytic computation of amplitudes in a general QFT. As a direct example and application, I will present new three-loop results which, for the first time, allowed a direct extraction of the quadrupole radiation contribution to the infrared structure of QCD. I will conclude with a description of the high-energy (Regge) limit and the first computation of the three-loop gluon Regge trajectory.

Per connettersi a zoom
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Feb
2
Gio
Vector boson fusion production of new physics at current and future colliders (Timothy Martonhelyi, Università di Melbourne) @ Aula 500 e online
Feb 2@3:00 pm–4:00 pm

Seminario di Fenomenologia

We clarify the role of vector boson fusion (VBF) in the production of heavy vector triplets at the LHC and the HL-⁠LHC. We point out that the presence of VBF production leads to an unavoidable rate of Drell-⁠Yan
(DY) production and highlight the subtle interplay between the falling parton luminosities and the increasing importance of VBF production
as the heavy vector mass increases. We discuss current LHC searches and
HL-⁠LHC projections in di-⁠boson and di-⁠lepton final states and demonstrate that VBF production outperforms DY production for resonance masses above 1 TeV in certain regions of the parameter space. We define two benchmark parameter points which provide
competitive production rates in vector boson fusion.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Feb
15
Mer
Inferring the impact of feedback on the matter distribution using the Sunyaev Zel’dovich effect (Dr. Shivam Pandey, Columbia University, NY) @ A603 e online
Feb 15@2:00 pm–3:00 pm

Seminario di Fenomenologia

Feedback from active galactic nuclei and stellar processes changes the matter distribution on small scales, leading to significant systematic uncertainty in weak lensing constraints on cosmology. In this talk, I will describe how the observable properties of group-scale halos can be used to constrain the impact of feedback on the matter distribution using Cosmology and Astrophysics with Machine Learning Simulations (CAMELS). By extending the results of previous work to smaller halo masses and higher wave numbers, k, we find that the baryon fraction in halos contains valuable information about the impact of feedback on the matter power spectrum. We will also explore how the thermal Sunyaev Zel’dovich (tSZ) signal from group-scale halos can provide similar information. Using recent Dark Energy Survey (DES) weak lensing and Atacama Cosmology Telescope (ACT) tSZ cross-correlation measurements and models trained on CAMELS, we obtain 10% constraints on the effects of feedback on the power spectrum at k ~ 5 h/Mpc. I will also demonstrate that with future surveys, it will be possible to constrain baryonic effects on the power spectrum to O(<1%) at k = 1 h/Mpc and O(3%) at k = 5 h/Mpc using the methods introduced here. Per connettersi a zoom: Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Feb
22
Mer
Charm in the proton (Prof. Stefano Forte, Universitá di Milano) @ 603 e online
Feb 22@2:00 pm–3:00 pm

Seminario di Fenomenologia

I present the first clear evidence for the presence of an intrinsic charm component in the proton. I recall the meaning of intrinsic charm and how intrinsic and perturbative charm can be distinguished from each other. I briefly review the NNPDF4.0 determination of the structure of the proton, and I discuss how its results, together with recent advanced tools for the evolution and matching of parton distributions, can be used for a separation of the perturbative and intrinsic charm components and a determination of the latter. I present results for the intrinsic charm component, I compare them to models, I discuss which current data have animpact on it, and briefly examine ongoing future improvements of the current result.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Feb
28
Mar
Signal-background interference effects in Higgs-mediated diphoton production beyond NLO (Federica Devoto, Oxford U.) @ 605 e online
Feb 28@2:00 pm–3:00 pm

Seminario di Fenomenologia

In this talk I will consider signal-background interference effects in Higgs-mediated diphoton production at the LHC. The inclusion of such effects results in a shift of the diphoton invariant mass distribution and in a destructive contribution to the total cross section. As pointed out in earlier works, one can exploit interference studies to put bounds on the Higgs boson decay width. After reviewing the Higgs interferometry framework I will present an extension of this analysis up to NNLO QCD in the soft-virtual approximation.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Mar
8
Mer
Theory-driven Quantum Machine Learning for HEP (Dr. Jack Araz, IPPP – Durham U.) @ Aula 603 e zoom
Mar 8@2:00 pm–3:00 pm

Seminario di Fenomenologia –

Machine Learning is, in most cases, powerful but a black-box application. In this talk, we will tackle this very problem from a quantum mechanics point of view, arguing that an optimisation problem, such as classification or anomaly detection, can be studied by “rephrasing” the problem as a quantum many-body system or a mixed state. Such an approach allows us to employ the entire arsenal of quantum theory for data analysis techniques while enabling exact representation for a quantum device. Hence this talk will present a small step towards fully theory-driven and interpretable quantum machine learning applications.

Per connettersi a zoom:—
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Mar
14
Mar
Wave-optics limit of the stochastic gravitational wave background (Alice Garoffolo, Leiden University) @ 500 e su zoom
Mar 14@2:00 pm–3:00 pm

Seminario di Fenomenologia –

The stochastic gravitational waves background is a rich resource of cosmological information, encoded both in its source statistics and its anisotropies. During their journey, the gravitational waves constituting the background encounter cosmic structures, which are able to modify the observed signal. According to the ratio between the wavelength of the wave, and the matter overdensities typical length-scale, interference and diffraction effects may arise, possibly boosting the signal’s amplitude or inducing a non-trivial polarization pattern. In this talk I will present results about the wave-optics limit of the stochastic gravitational wave background, and describe how we can use them to gain information about the matter content of the Universe.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271Meeting ID: 857 318 5271

Mar
16
Gio
Classification of Rational Conformal Field Theories With A Single Critical Exponent (Dr. Suni Mukhi, CERN and IISER, Pune)) @ 501 e su zoom
Mar 16@2:00 pm–3:00 pm

Seminario di Fisica Teorica –

I will present the classification of all unitary, rational conformal field theories with one non-trivial primary and central charge c < 25. (with Brandon Rayhaun, arXiv: 2208.05486). I will also, more briefly, review a partial classification of theories with two nontrivial primaries, as well as some new predictions on the existence of meromorphic CFT with central charge 32.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Mar
22
Mer
Relaxed hydrodynamics (in an electric field) (Daniel Brattan) @ Aula 603 e zoom
Mar 22@2:00 pm–3:00 pm

Seminario di Fisica Teorica –

Hydrodynamics is the effective theory that governs the transport of charge, energy and momentum at late times and large distances. In certain circumstances this description must be modified to include the fact that these charges decay very slowly; for example when there are chemical processes or spatial translation invariance is broken. In this talk I will primarily discuss how to incorporate such “relaxation” processes into the effective theory of a fluid driven by an electric field. Given sufficient time I will place this work in the larger context of the relaxed hydrodynamics programme and tease new results.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271

Mar
29
Mer
Axion dark matter in the sky (Marco Regis, Università di Torino) @ Aula 603 e zoom
Mar 29@2:00 pm–3:00 pm

Seminario di Fenomenologia –

Axion-like particles (ALPs) are one of the most attractive solutions to the dark matter issue.
In this talk, I will discuss how to search for ALPs in astrophysical structures.
After some introduction, I will focus on the emission associated with their decay into photons.
The discussion will involve different ALP mass ranges and wavelength bands.

Per connettersi a zoom:
Topic: Theory and Pheno seminars
https://infn-it.zoom.us/j/8573185271
Meeting ID: 857 318 5271