Origin of neutrino masses, dark matter, leptogenesis, and inflation in a seesaw model with triplets

TL;DR

This paper proposes a comprehensive model extending the Standard Model with triplet fermions and scalars to simultaneously explain neutrino masses, dark matter, baryogenesis, and inflation, consistent with current cosmological observations.

Contribution

It introduces a unified framework with specific Z2 symmetries that accounts for multiple fundamental cosmological phenomena in a single model.

Findings

The model explains neutrino oscillation data and dark matter relic density.

Inflationary parameters are consistent with Planck-2018 constraints.

The model can generate the observed baryon asymmetry at TeV scales.

Abstract

We consider a new physics model, where the Standard Model (SM) is extended by hyperchargeless $Y=0$ triplet fermions and Higgs triplet with hypercharge $Y=2$. The first two generation fermion triplets are even under the $Z_2$ transformation. In contrast, the third fermion triplet and scalar triplet are odd under the same $Z_2$ transformation. It is a unifying framework for the simultaneous explanation of neutrino mass and mixing, dark matter, baryogenesis, inflation, and reheating temperature of the Universe. The two $Z_2$ even neutral fermions explain the neutrino low energy variables, whereas the third one can serve as a viable dark matter candidate, explaining the exact relic density. The scalar triplet is coupled nonminimally to gravity and forms the inflaton. We calculate the inflationary parameters and find them consistent with the new Planck-2018 constraints. We also do the reheating analysis for the inflaton decays/annihilations to relativistic SM particles. The triplet fermions associated with $Z_2$ even sector can provide the observed baryon asymmetry of the Universe at the TeV scale.