Emergent Dark Matter, Baryon, and Lepton Numbers

TL;DR

This paper introduces a novel early-universe mechanism for transferring asymmetries from baryons or leptons to dark matter via dynamically induced mass mixing, avoiding complex higher-dimensional operators.

Contribution

It proposes a new mass mixing mechanism for asymmetric dark matter transfer, applicable during early universe phase transitions and involving generic operators.

Findings

Mass mixing can generate dark matter asymmetries from baryon/lepton asymmetries.

Models accommodate dark matter masses from 1 GeV to 100 TeV.

The mechanism simplifies asymmetric dark matter models by removing the need for higher-dimensional operators.

Abstract

We present a new mechanism for transferring a pre-existing lepton or baryon asymmetry to a dark matter asymmetry that relies on mass mixing which is dynamically induced in the early universe. Such mixing can succeed with only generic scales and operators and can give rise to distinctive relationships between the asymmetries in the two sectors. The mixing eliminates the need for the type of additional higher-dimensional operators that are inherent to many current asymmetric dark matter models. We consider several implementations of this idea. In one model, mass mixing is temporarily induced during a two-stage electroweak phase transition in a two Higgs doublet model. In the other class of models, mass mixing is induced by large field vacuum expectation values at high temperatures - either moduli fields or even more generic kinetic terms. Mass mixing models of this type can readily accommodate asymmetric dark matter masses ranging from 1 GeV to 100 TeV and expand the scope of possible relationships between the dark and visible sectors in such models.