Apostolos Pilaftsis: Resonant Leptogenesis and Charged Lepton Flavour Violation

by Apostolos Pilaftsis (University of Manchester)

Friday 19 May 2023, 12:30 → 14:00 Europe/London

Niels Bohr Seminar Room (Schuster)

The observed ultralight neutrinos may hold the key to understanding several puzzles in our universe, including the origin of the matter–antimatter asymmetry and the nature of the dark matter. In this talk, 
I will present a novel class of resonant leptogenesis (RL) models where the ultralight neutrinos acquire their observed mass through a symmetry-motivated construction rather than through the usual seesaw mechanism. I will consider an extension of the Standard Model with three singlet neutrinos that have mass splittings comparable to their decay widths. I will show how such a tri-resonant structure leads to an appreciable increase in the observed CP asymmetry over that found previously in typical bi-resonant models. In particular, I will highlight the fact that small variations at high temperatures can have major implications for the evolution of the baryon asymmetry when the singlet neutrino mass scale is below 
100 GeV. I will then illustrate how this variation significantly affects the ability to find successful models of leptogenesis at these low masses. Finally, I will give predictions of tri-RL models for charged lepton-flavour and lepton-number violation and discuss the prospects for them to be tested at the LHC and in current and projected experiments.

 

The seminar will be given in person in Niels Bohr, Schuster.

PILAFTSIS_tri-RL_UoM_2023.pdf