CoGeNT Interpretations

TL;DR

This paper investigates various dark matter interaction models to explain the CoGeNT excess events, examining their compatibility with existing constraints and potential to unify signals from CoGeNT and DAMA.

Contribution

It explores generalized dark matter scattering models, including momentum dependence and inelastic interactions, to reconcile the CoGeNT excess with other experimental limits.

Findings

Some generalized interactions can explain CoGeNT events without conflicting with constraints.

Momentum-dependent couplings can align CoGeNT and DAMA signals.

A dark matter model with a light boson mediator can support these scenarios.

Abstract

Recently, the CoGeNT experiment has reported events in excess of expected background. We analyze dark matter scenarios which can potentially explain this signal. Under the standard case of spin independent scattering with equal couplings to protons and neutrons, we find significant tensions with existing constraints. Consistency with these limits is possible if a large fraction of the putative signal events is coming from an additional source of experimental background. In this case, dark matter recoils cannot be said to explain the excess, but are consistent with it. We also investigate modifications to dark matter scattering that can evade the null experiments. In particular, we explore generalized spin independent couplings to protons and neutrons, spin dependent couplings, momentum dependent scattering, and inelastic interactions. We find that some of these generalizations can explain most of the CoGeNT events without violation of other constraints. Generalized couplings with some momentum dependence, allows further consistency with the DAMA modulation signal, realizing a scenario where both CoGeNT and DAMA signals are coming from dark matter. A model with dark matter interacting and annihilating into a new light boson can realize most of the scenarios considered.