Archimedean Lever Leptogenesis

TL;DR

This paper explores a novel mechanism for weak scale leptogenesis involving TeV-scale right-handed neutrinos, a light scalar, and fermion dark matter, proposing a two-component dark matter scenario with early Universe dynamics.

Contribution

It introduces a new leptogenesis model at the weak scale utilizing scalar displacement and fermion mass effects, with implications for dark matter composition.

Findings

Two-component dark matter from scalar and fermion

Leptogenesis feasible at TeV scale with early Universe scalar displacement

Parameter space allows for viable dark matter candidates

Abstract

We propose that weak scale leptogenesis via $\sim 10$ TeV scale right-handed neutrinos could be possible if their couplings had transitory larger values in the early Universe. The requisite lifted parameters can be attained if a light scalar $\phi$ is displaced a long distance from its origin by the thermal population of fermions $X$ that become massive before electroweak symmetry breaking. The fermion $X$ can be a viable dark matter candidate; for suitable choice of parameters, the light scalar itself can be dark matter through a misalignment mechanism. We find that a two-component DM population made up of both $X$ and $\phi$ is a typical outcome in our framework.