| | |
22-09-2025 (aula F - V della Vasca Navale n. 84)
|
| |
ore 14:30
| Carducci Marco (DOTTORATO IN FISICA) | Introduzione alla fisica modulare
Durante l'evoluzione della stringa, questa spanna il cosiddetto "worldsheet" bidimensionale. Data la simmetria di Weyl, questo ci porta allo studio della teoria conforme ed i suoi generatori di Virasoro. La topologia della stringa permette l'esistenza di due varianti: stringa aperta o stringa chiusa. Un loop chiuso della stringa chiusa ci restituisce la funzione di partizione che gode della cosidetta simmetria modulare. Questa, a seguito del paper seminale di Ferruccio, professore a Padova, è diventata di interesse anche nell'ambito della fenomenologia.
| |
ore 15:00
| Fiorentino Vincenzo (DOTTORATO IN FISICA) | The QCD axion: astrophysical bounds and finite density effects
Providing an elegant solution to the strong CP problem, and representing a promising candidate for cold dark matter, the QCD axion is one of the best motivated light BSM particles. For this reason, the experimental effort in the search for the axion has increased drastically in recent times, with new experimental proposals like IAXO at DESY, and FLASH at the INFN. This makes it necessary to provide highly precise and reliable bounds on the axion parameter space. In this talk I will give an introduction to the supernova axion bound, focusing in particular on the role of finite density corrections, which are important in the supernova and have been neglected in the past. Additionally, I will describe how the so-called nucleophobic axion models, for which the supernova bound gets sizeably relaxed, survive finite density effects. Finally, I will provide some insight on more recent developments.
| |
ore 16:00
| Rettaroli Mirko (DOTTORATO IN FISICA) | Viable fit to neutrino observables in possible U(2) flavor models
The explanation of neutrino masses and mixing still represents one of the open questions of the so-called “SM flavor puzzle” today. The purpose of my work is to provide a possible explanation of this problem, introducing an extension of the Standard Model based on a continuous U(2) flavor symmetry (which is locally isomorphic to SU(2) x U(1)), indicated as U(2)F . This symmetry is spontaneously broken by the VEVs of two scalar fields, called flavons. Since the flavon VEVs depend on two small parameters, all hierarchies in fermion masses and mixings arise from powers of these small order parameters.
Assuming that neutrinos are Majorana particles and that the light neutrinos take mass via the type-I see-saw mechanism, we can obtain a list of possible structures for the neutrino mass matrix (which we call patterns), depending on the choice of the U(2)F quantum numbers for the three RH neutrino representations.
After a numerical fit of these matrices to the neutrino observables, we obtain 13 viable patterns, which provide us interesting predictions on neutrino observables, such as the effective electron neutrino mass and the effective Majorana neutrino mass, and also on BSM phenomena such as LFV decays.
| |
|
Ph.D. in Physics