From Dirac neutrino masses to baryonic and dark matter asymmetries

TL;DR

This paper proposes a model with a dark sector mirroring the Standard Model, where decays of heavy particles generate both baryon asymmetry and dark matter relic density, linking neutrino masses to cosmological asymmetries.

Contribution

It introduces a novel framework connecting Dirac neutrino masses with baryon and dark matter asymmetries via messenger sectors in a dark mirror model.

Findings

Dark nucleon mass around 5 GeV as dark matter candidate

Simultaneous generation of baryon and dark matter asymmetries

Neutrino masses derived from integrating out heavy mediators

Abstract

We consider an SU(3)'_c\times SU(2)'_L\times U(1)'_Y dark sector, parallel to the SU(3)_c\times SU(2)_L\times U(1)_Y ordinary sector. The hypercharges, baryon numbers and lepton numbers in the dark sector are opposite to those in the ordinary sector. We further introduce three types of messenger sectors: (i) two or more gauge-singlet Dirac fermions, (ii) two or more [SU(2)_L\times SU(2)'_L]-bidoublet Higgs scalars, (iii) at least one gauge-singlet Dirac fermion and at least one [SU(2)_L\times SU(2)'_L]-bidoublet Higgs scalar. The lepton number conserving decays of the heavy fermion singlet(s) and/or Higgs bidoublet(s) can simultaneously generate a lepton asymmetry in the [SU(2)_L]-doublet leptons and an opposite lepton asymmetry in the [SU(2)'_L]-doublet leptons to account for the cosmological baryon asymmetry and dark matter relic density, respectively. The lightest dark nucleon as the dark matter particle should have a mass about 5 GeV. By integrating out the heavy fermion singlet(s) and/or Higgs bidoublet(s), we can obtain three light Dirac neutrinos composed of the ordinary and dark neutrinos. If a mirror discrete symmetry is further imposed, our models will not require more unknown parameters than the traditional type-I, type-II or type-I+II seesaw models.