Non-Unitary Lepton Mixing Matrix, Leptogenesis and Low Energy CP Violation

TL;DR

This paper explores how non-unitary lepton mixing matrices can link low-energy CP violation with leptogenesis, potentially leading to observable effects in neutrino experiments and baryon asymmetry generation.

Contribution

It demonstrates that non-unitarity in lepton mixing matrices can connect low-energy CP violation with leptogenesis, unlike the standard case.

Findings

Non-unitary matrices induce observable CP phases.

Potential observable effects in neutrino oscillations.

Possible contributions to baryon asymmetry.

Abstract

It is well-known that for unflavored leptogenesis there is in general no connection between low and high energy CP violation. We stress that for a non-unitary lepton mixing matrix this may not be the case. We give an illustrative example for this connection and show that the non-standard CP phases that are induced by non-unitarity can be responsible for observable effects in neutrino oscillation experiments as well as for the generation of the baryon asymmetry of the Universe. Lepton Flavor Violation in decays such as tau -> mu gamma can also be induced at an observable level. We also comment on neutrino mass limits from leptogenesis, which get barely modified in case of a non-unitary mixing matrix.