Neutrino CP violation and sign of baryon asymmetry in the minimal seesaw model

TL;DR

This paper explores how the CP violating phase in the lepton sector relates to the observed baryon asymmetry in the universe within a minimal seesaw framework, linking low-energy neutrino data to cosmological observations.

Contribution

It establishes a direct connection between the low-energy CP phase and baryon asymmetry in a minimal seesaw model with two right-handed neutrinos and trimaximal mixing.

Findings

The sign of the CP violating phase is determined by the baryon asymmetry.

The model is consistent with recent T2K and NOvA data for normal hierarchy.

The Dirac neutrino mass matrix is fixed by the observed asymmetry.

Abstract

We discuss the correlation between the CP violating Dirac phase of the lepton mixing matrix and the cosmological baryon asymmetry based on the leptogenesis in the minimal seesaw model with two right-handed Majorana neutrinos and the trimaximal mixing for neutrino flavors. The sign of the CP violating Dirac phase at low energy is fixed by the observed cosmological baryon asymmetry since there is only one phase parameter in the model. According to the recent T2K and NO$\nu$A data of the CP violation, the Dirac neutrino mass matrix of our model is fixed only for the normal hierarchy of neutrino masses.