Faint Light from Dark Matter: Classifying and Constraining Dark Matter-Photon Effective Operators

TL;DR

This paper classifies effective operators that enable dark matter to interact with photons, providing model-independent constraints from detection experiments and analyzing implications for various dark matter models.

Contribution

It offers a comprehensive classification of DM-photon operators and derives constraints applicable to a wide range of dark matter models.

Findings

Constraints on DM-photon operators from detection experiments

Classification of operators for Dirac/Majorana fermions and scalars

Implications for UV-complete dark matter models

Abstract

Even if Dark Matter (DM) is neutral under electromagnetism, it can still interact with the Standard Model (SM) via photon exchange from higher-dimensional operators. Here we classify the general effective operators coupling DM to photons, distinguishing between Dirac/Majorana fermion and complex/real scalar DM. We provide model-independent constraints on these operators from direct and indirect detection. We also constrain various DM-lepton operators, which induce DM-photon interactions via RG running or which typically arise in sensible UV-completions. This provides a simple way to quickly assess constraints on any DM model that interacts mainly via photon exchange or couples to SM leptons.