Archimedean Lever Leptogenesis

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.