HEP Theory Journal Club

A little theory of everything

Jim Cline

McGill

I present a minimal model that attempts to address the main missing ingredients of the standard model: inflation, baryogenesis, dark matter, and the origin of neutrino masses. We introduce a complex inflaton that decays into three generations of GeV-scale heavy neutral leptons, creating a lepton asymmetry during inflation. One HNL is stable and provides (partially) asymmetric dark matter. A light scalar singlet is needed to suppress its symmetric relic density. Neutrino masses are generated by the usual seesaw mechanism, with heavy right-handed neutrinos above the inflation scale, and an MFV-like ansatz that relates neutrino masses to the HNL couplings, that are then linked to the light neutrino properties with only one adjustable parameter. The stability of dark matter implies the lightest neutrino is massless. The model is highly testable, and could explain excess events recently seen by KOTO.