Categoria: News

Martedì 7 marzo 2023

ore 15:00

Sala 131 e on line su piattaforma ZOOM

Abstract:

We present the status of the determination of the W boson mass at hadron colliders, discussing the main sources of uncertainty, in a theory perspective, reviewing the results from the Tevatron and LHC experiments. We then introduce a new observable, arXiv:2301.04059 , sensitive to the W boson mass, whose features are particularly suitable for a systematic discussion of the different uncertainties affecting the MW determination.

We demonstrate that one of the most problematic elements in the modelling of the kinematical distributions, namely the perturbative QCD corrections, is under control, with a residual uncertainty at the +-5 MeV level.

Martedi 31 gennaio alle ore 15.00 
Abstract: Magnetic resonance imaging (MRI) is a powerful diagnostic technique able to provide high spatial resolution and excellent contrast for soft tissues in a non-invasive manner, thanks to the use of non-ionizing radiation. However, MRI mainly remains a qualitative method, since the pointwise intensity of an MR image is modulated by the underlying tissue properties but does not directly represent a biophysical quantity, whose measurement requires tailored acquisition techniques  with an excessive duration for the clinical routine.
For this reason, many approaches to accelerate these quantitative measurements have been developed during the years, both with more efficient signal sampling techniques and advanced image reconstruction methods.
In this seminar, the basic principles of quantitative MRI will be presented, together with an overview of the main acceleration strategies used to enable its application in a clinical setting. In addition, the possible future developments in the context of the new INFN PREDATOR project (Pushing quantitative magnetic REsonance imaging using Deep learning And compuTatiOnally efficient Reconstruction methods) will be discussed.

Il seminario si terrà in presenza nella sala 250 e via zoom al seguente indirizzo:
https://infn-it.zoom.us/j/84261721878?pwd=MDZNaGdBUlcvUUJXa2phSHZVZk5sdz09

Giovedi 19 gennaio 2023 ore 14:00

Abstract:
Despite many theoretical and experimental indications pointing to the existence of new physics, the lack of direct evidence suggests the presence of a mass gap. Effective Field Theories (EFT) provide the optimal theoretical framework to describe the possible effects of such new physics. However, the great diversity of UV possibilities and the complexity of (one-loop) matching computations difficult the connection between EFT analyses and their interpretation in terms of precise UV models. Recent advancements in the path-integral formulation of one-loop EFT matching (and running) provide a promising approach to overcoming this issue. In this seminar, I will review the state-of-the-art path-integral techniques and present the first (proof of concept) release of Matchete: A Mathematica tool that, using path-integral methods, will completely automate one-loop matching of arbitrary weakly-coupled UV theories to their EFTs.

Il seminario si terrà in presenza nella sala Galilei (131) e via zoom al seguente indirizzo: https://infn-it.zoom.us/j/84261721878?pwd=MDZNaGdBUlcvUUJXa2phSHZVZk5sdz09

Lunedi 23 gennaio 23 ore 15:00

Abstract:
In comparison to photon radiotherapy, particle beam radiotherapy (mostly protons and carbon ions are used) results in a lower radiation dose to normal tissue, reducing long– term complications and increasing the quality of life of patients. However, the dose distribution delivered during particle therapy is quite sensitive to anatomical changes in the patient, particle range uncertainties and patient setup errors. Because of this, several techniques for in–vivo dose delivery verification have and are being developed. The most investigated method is positron emission tomography (PET) of the positron emitters that are created by the particles via nuclear reactions in the patient. The PET signal is obviously delayed by the radioactive decay half–life. For most positron emitters this precludes real–time feedback and leaves room for biological washout. I will report on investigations towards real–time verification using PET during proton, helium ion and heavy ion therapy. At the University Medical Center Groningen, we are investigating imaging of 12 N, with a half–life of just 11 ms, produced by the proton or helium beam in the patient. I will report on recent proof–of–principle demonstrations of the range accuracy in homogeneous targets, and discuss our present research to
establish the clinical relevance on the basis of irradiations of an anthropomorphic head phantom. Treatment with positron emitting radioactive heavy ions gives a much stronger PET signal which is more closely correlated to the Bragg peak compared to treatment with stable heavy ions. Within the BARB project at the GSI Helmholtzzentrum für Schwerionenforschung, we have investigated the precision with which the range of 10,11 C and 14,15 O can be measured using PET. The design and outcome of these experiments will be discussed.

Il seminario si terrà in presenza nella sala Galilei (131) e via zoom al seguente indirizzo: https://infn-it.zoom.us/j/84261721878?pwd=MDZNaGdBUlcvUUJXa2phSHZVZk5sdz09

Abstract: The muon is an elementary particle, a short-lived cousin of the electron. Since about 20 years the calculation of its magnetic moment disagrees with its measurement, indicating that a not-yet-known particle or force might be influencing the muon. An experiment at the Fermi National Accelerator Laboratory (FNAL,US) confirmed this puzzling discrepancy with an announcement in April 2021. The event received significant media attention. 

At the same time our group published a new ab-inito calculation, based on lattice formulation of quantum chromodynamics (lattice QCD), which challenged previous computations and brought the theoretical prediction closer to the experimental value. According to this result, no new forces or particles are neccessary to explain the FNAL and previous measurements.

Currently, the question if there is any new physics in the muon magnetic moment, is open. Since 2021 several new independent lattice QCD computations have appeared, there are updates of the old style theory approach, and also comparisons of the two approaches. In the meantime the FNAL experiment keeps on gathering new data.

The talk will give a review of these efforts with the main focus on our original lattice computation.
Il seminario si terrà in presenza nella sala riunioni 250 e via zoom al seguente indirizzo:  https://infn-it.zoom.us/j/84261721878?pwd=MDZNaGdBUlcvUUJXa2phSHZVZk5sdz09

Abstract: Control over the quantum states of atoms and molecules can lead to a fundamentally new understanding of how these particles interact and react. This knowledge has the potential to impact our ability to probe processes in planetary atmospheres and in the interstellar medium. Experimental techniques developed for control and measurement of atoms is now being used to study more and more complex molecules. We study these rich systems at low temperatures where we can trap and examine their properties for many minutes, as compared to small fractions of a second in standard experiments. Using these cold, trapped molecular ions, we investigate mechanisms of ion-molecule reactions to gain insights into the mechanisms driving these processes. In particular, we explore possible mechanisms that may initiate growth of carbon chains in the interstellar medium.

Abstract:

Artificial Intelligence for digital REStoration of Cultural Heritage (AIRES-CH) is a project focused on a creation of a cloud-native web app for the digital restoration of pictorial artworks through Computer Vision technologies applied to nuclear imaging raw data, such as X-Ray Fluorescence (XRF). In this talk, after a really brief introduction on nuclear imaging technologies, I will show that the task of associating an RGB colour image to an XRF imaging raw data is feasible by means of a multidimensional neural network, by discussing the Deep Neural Network models pipeline (training dataset composition, models’ architecture definition, training process, hyperparameter optimisation, validation); I will close with a brief discussion on how the trained neural network is employed in the cloud-native web application for XRF raw data real-time analysis.