Speaker
Matthias Le Dall
(University of Victoria)
Description
The baryonic matter-antimatter asymmetry in the universe is a well known fact, and measured to be $n_B-n_{\overline
B}\sim6\cdot10^{-10}n_\gamma$. Standard Leptogenesis is among the simplest and most natural theories to explain the asymmetry, making use of the
family of three heavy right-handed Majorana neutrinos, already well motivated to explain the active neutrino masses, which puts the model at mass
scales of the order $M\sim10^9$GeV and above. We enlarge the model with a hidden sector consisting of a singlet scalar $S$, coupled via the Higgs portal
$\beta SHH$, and a RHN-scalar coupling $\alpha SNN$. These two interactions open up new sources of CP-asymmetry, with a scaling as
$\epsilon\propto\alpha\beta/M$. The direct consequence is the possibility of lowering the RHN mass scale, yet keeping the CP-asymmetry at a level
necessary to generate the baryon asymmetry. We explore the dynamics of this model, and show it allows for RHN mass scales as low as the Electroweak
scale.
Paper to appear shortly, "Leptogenesis and the Higgs Portal", Matthias Le Dall and Adam Ritz.
Author
Matthias Le Dall
(University of Victoria)
Co-author
Adam Ritz
(University of Victoria)
