Speaker
Description
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 $SU(2) \times U(1)$), 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 small parameters $\epsilon_{\phi,\chi} \sim O(0.01)$, 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 this 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 $m_\beta$ and the effective Majorana neutrino mass $m_{\beta\beta}$, and also on BSM phenomena such as LFV decays.
