Sharing but not Caring: Dark Matter and the Baryon Asymmetry of the Universe

TL;DR

This paper explores models where Dark Matter carries baryon/lepton numbers, sharing asymmetry with the Standard Model, and investigates their phenomenology at colliders and detection experiments.

Contribution

It introduces minimal scenarios linking Dark Matter to the Standard Model via operators with baryon/lepton numbers, detailing asymmetry sharing mechanisms and collider signatures.

Findings

Operators fix asymmetry transfer between sectors.

Rich LHC phenomenology with specific signatures.

Framework consistent with observed baryon asymmetry.

Abstract

We consider scenarios where Dark Matter (DM) particles carry baryon and/or lepton numbers, which can be defined if there exist operators connecting the dark to the visible sector. As a result, the DM fields become intimately linked to the Standard Model (SM) ones and can be maximally asymmetric just like the ordinary matter. In particular, we discuss minimal scenarios where the DM is a complex scalar or a Dirac fermion coupled to operators with nonzero baryon and/or lepton numbers, and that consist of only SM fields. We consider an initial asymmetry stored in either the SM or the DM sector; the main role of these operators is to properly $share$ the asymmetry between the two sectors, in accordance with observations. After the chemical decoupling, the DM and SM sectors do $not$ $care$ about each other as there is only an ineffective communication between them. Once the DM mass is specified, the Wilson coefficients of these operators are fixed by the requirement of the correct transfer of the asymmetry. We study the phenomenology of this framework at colliders, direct detection and indirect detection experiments. In particular, the LHC phenomenology is very rich and can be tested in different channels such as the two same-sign leptons with two jets, monojet and monojet with a monolepton.