Calendar

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

Giu
21
Mer
Gluon scattering in AdS from supersymmetric localization (Pietro Ferrero – Simons Center) @ 602
Giu 21@2:00 pm–3:00 pm

Seminario di Fisica Teorica INFN/DIFI

I will discuss some of the recent progress made in the computation of holographic correlators describing the scattering of gluons in anti de Sitter space. I will focus in particular on a special AdS_5 model, arising from N D3 branes probing a D7 brane singularity, which is the holographic description of a certain 4d N=2 USp(2N) gauge theory with matter. The (mass-deformed) partition function of such gauge theory gives a non-perturbative integral constraint that the holographic correlators must satisfy, thus allowing to fix a number of coefficients that cannot be obtained from bootstrap considerations alone. Among our results: we obtain a finite coupling expression for the first higher-derivative corrections in terms of modular functions, we derive the first three orders in the small alpha’ expansion of the Veneziano amplitude in AdS_5xS^3 and we completely fix a one-loop ambiguity in the gluon amplitude without a reference to the effective action on the D7 branes, which is not known.

Set
13
Mer
EFT, positivity, and the electroweak hierarchy (Tevong You, King’s College London) @ A603 e online
Set 13@3:00 pm–5:00 pm

Seminario di Fenomenologia-

The Standard Model (SM) is an Effective Field Theory (EFT) with an electroweak hierarchy problem associated to an unnaturally light Higgs. After introducing the concept of the SM EFT and the naturalness problem, I will present the possibility that an unnatural hierarchy between certain higher-dimensional operator coefficients in a low-energy EFT would automatically imply that the Higgs’ vacuum expectation value is hierarchically smaller than the EFT cut-off, assuming the EFT emerged from a unitary, causal and local UV completion. Future colliders may have the sensitivity to infer such a pattern of coefficients for a little hierarchy with an EFT cut-off up to O(10) TeV.

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

Ott
11
Mer
The O(N) Monolith reloaded: Sum rules and Form Factor Bootstrap @ Aula 500 e online
Ott 11@2:30 pm–3:30 pm

Seminario di Fisica Teorica (Dr. Alessandro Georgoudis, Queen Mary)

In this talk I will present the S-matrix bootstrap program and its application to the study of 2d gapped and UV complete QFTs. In our work we extend the known results from pure S-matrix bootstrap by including into the set-up form factors and spectral functions of the stress energy tensor and conserved currents. I will explain how this extended set-up works and show how the associated sum rules allow us to put bounds on quantities like the central charge of the underlying conformal theories in the UV. Based on work with L. Córdova, M. Correia and A. Vuignier.

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

Ott
18
Mer
Black hole thermodynamics from N=4 SYM: perturbations beyond supersymmetry and extremality (Alejandro Cabo Bizet, Università del Salento) @ Aula 500 e online
Ott 18@2:00 pm–3:00 pm

Seminario di Fisica Teorica-

The Bekenstein-Hawking entropy of supersymmetric and extremal (BPS) black holes has a precise statistical interpretation in the context of AdS/CFT duality. For non-BPS anti-de Sitter (AdS) black holes in dimensions larger than three, such a precise statistical interpretation has not been found yet. After reviewing the microscopic interpretation of the Bekenstein-Hawking entropy for large BPS black holes in five dimensional AdS, and time permitting, I will explain how some perturbative corrections, deviating from supersymmetry and extremality, can be computed in four-dimensional maximally supersymmetric SU(N) Yang Mills theory.

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

Ott
20
Ven
First result of a search for diffuse supernova neutrino background in SK-Gd experiment (Dr. Masayuki Harada, Okayama University, Japan) @ Aula 605
Ott 20@11:00 am–12:00 pm

Diffuse supernova neutrino background (DSNB), which is an integrated flux of neutrinos from all past core-collapse supernovae (CCSNe), are eagerly studied in the worldwide experiment because the detection of DNSB flux makes investigation about the star formation history as well as the neutrino emission from CCSNe.

Since 2020, Super-Kamiokande (SK) detector has been updated by loading gadolinium (Gd) as a new experimental phase, “SK-Gd”. In the SK-Gd experiment, neutrons can be efficiently identified due to high cross-section and high energy gamma-ray emission of thermal neutron capture on Gd. This enables to search low-energy electron antineutrinos such as a signal of DSNB via inverse-beta decay.
Until July 2022, the observation was operated with the 0.01% Gd mass concentration, termed as SK-VI. The neutron capture fraction on Gd is about 50% at that time. In this period, we operated neutron source calibration and obtained characteristics about the neutron identification in SK-Gd detector.
Using the whole period of SK-VI, we searched for astrophysical electron antineutrinos with the energy of O(10) MeV in SK-Gd with a 22.5×552 kton·day exposure at 0.01% Gd mass concentration for a first time in SK-Gd experiment.
This seminar provides the result of the search and prospects for future observation.

Ott
25
Mer
Travels through modified gravity (Peter Dusnby, University of Cape Town) @ Aula 500 e online
Ott 25@2:30 pm–3:30 pm

Seminario di Fisica Teorica –

Over the past two decades, f(R) gravity has been at the forefront of providing an alternative to dynamical dark energy to explain the origin of late-time acceleration in the universe. This talk will provide a survey of work that has been done in this area using covariant methods, dealing with diverse topics from cosmological dynamics to gravitational lensing and perturbations of black holes.

Per connettersi a zoom:

https://infn-it.zoom.us/j/93341311520?pwd=RklTcFFVWjdtUzR5TUZKM3V1TjJiQT09

Nov
8
Mer
Heavy Barions and new Interacting Boson Fermion Fermion Model results (Hugo Garcia Tecocoatzi, INFN Genova) @ Aula 500 e online
Nov 8@2:00 pm–3:00 pm

Seminario di Fisica Teorica-

In the first part of the presentation, I will present a study of the spectra and strong decay widths of heavy baryons. The masses of single heavy baryons up to the D-wave have been calculated within a constituent quark model, employing both the three-quark and quark-diquark schemes. The decay widths of the ground and excited single heavy baryons into the heavy single baryon-(vector/pseudoscalar) meson pairs and the (octet/ decuplet) baryon-
(pseudoscalar/vector) heavy meson pairs, have been calculated. Moreover, I will discuss why the presence or absence of the ρ-mode excitations in the experimental spectrum is the key to distinguishing between the quark-diquark and three-quark behaviours, as it was originally pointed out in. The quantum number assignments and predictions for mass spectra and strong-decay widths are in agreement with the available data. These findings provide valuable
guidance for future measurements in experiments as ATLAS, CMS, LHCb, Belle, and Belle II.
In the second part of this talk, I will present a new application of the Interacting Boson Fermion-Fermion Model (IBFFM) for describing double charge exchange reactions. The study of double charge exchange reactions induced by heavy ions involving candidate nuclei for neutrinoless double beta decay is a complex task carried out by the NUMEN collaboration [5], to which I belong. This investigation faces the intricacies of complex odd-odd intermediate nuclei in sequential double charge exchange processes. I will offer a comprehensive description of heavy odd-odd nuclei using the (IBFFM). Additionally, I will outline the methodology for describing transfer operators within this framework.
Finally, I will explore the potential applications of our results in future reaction codes for describing double charge exchange reactions.

Per connettersi a zoom:

https://infn-it.zoom.us/j/93341311520?pwd=RklTcFFVWjdtUzR5TUZKM3V1TjJiQT09