Leptogenesis with TeV Scale $W_R$

TL;DR

This paper proposes an alternative left-right symmetric model where TeV-scale $W_R$ bosons do not hinder leptogenesis, contrasting with conventional models, and suggests that discovering $W_R$ at the LHC would support this new scenario.

Contribution

It introduces a quark seesaw realization of left-right symmetry that avoids the usual $W_R$ mass bound, enabling leptogenesis at the TeV scale through scalar decays.

Findings

Leptogenesis can occur without a high $W_R$ mass bound in the new model.

Detection of $W_R$ at LHC would support the alternative model.

The model also addresses the strong CP problem.

Abstract

Successful leptogenesis within the conventional TeV-scale left-right implementation of type-I seesaw has been shown to require that the mass of the right-handed $W_R^\pm$ boson should have a lower bound much above the reach of the Large Hadron Collider. This bound arises from the necessity to suppress the washout of lepton asymmetry due to $W_R^\pm$-mediated $\Delta L\neq 0$ processes. We show that in an alternative quark seesaw realization of left-right symmetry, the above bound can be avoided. Lepton asymmetry in this model is generated not via the usual right-handed neutrino decay but rather via the decay of new heavy scalars producing an asymmetry in the $B-L$ carrying Higgs triplets responsible for type-II seesaw, whose subsequent decay leads to the lepton asymmetry. This result implies that any evidence for $W_R$ at the LHC 14 will point towards this alternative realization of left-right symmetry, which is also known to solve the strong CP problem.