Claudia Hagedorn (IFIC, Valencia)
2:00pm Friday July 14, 2023
Geoff Opat Seminar Room
Phenomenology of low-scale seesaw with flavour and CP symmetries
We consider a type-I seesaw framework endowed with a flavour symmetry, belonging to the series of non-abelian groups Delta (3 n^2) and Delta (6 n^2), and a CP symmetry. Breaking these symmetries in a non-trivial way results in the right-handed neutrinos being degenerate in mass up to possible (further) symmetry-breaking splittings, while the neutrino Yukawa coupling matrix encodes the entire flavour structure in the neutrino sector. For a fixed combination of flavour and CP symmetry and residual groups, this matrix contains five real free parameters. Four of them are determined by the light neutrino mass spectrum and by accommodating experimental data on lepton mixing well, while the fifth parameter is related to right-handed neutrinos. We scrutinise for all four types of lepton mixing patterns the potential to generate the baryon asymmetry of the Universe through low-scale leptogenesis numerically and analytically. The possibility to directly search for the heavy neutrinos is also commented.