Dark matter coupling to electroweak gauge and Higgs bosons: an effective field theory approach

TL;DR

This paper investigates how dark matter particles, potentially scalar or fermionic, could interact with standard-model particles through electroweak and Higgs bosons using effective field theory, analyzing annihilation processes and detection signals.

Contribution

It systematically explores WIMP couplings to electroweak and Higgs bosons via effective operators up to dimension 8, providing detailed annihilation calculations and phenomenological implications.

Findings

Calculated dark matter annihilation channels and cross sections.

Identified correlations among different final states.

Estimated the effective field theory scale for correct relic density.

Abstract

If dark matter is a new species of particle produced in the early universe as a cold thermal relic (a weakly-interacting massive particle-WIMP), its present abundance, its scattering with matter in direct-detection experiments, its present-day annihilation signature in indirect-detection experiments, and its production and detection at colliders, depend crucially on the WIMP coupling to standard-model (SM) particles. It is usually assumed that the WIMP couples to the SM sector through its interactions with quarks and leptons. In this paper we explore the possibility that the WIMP coupling to the SM sector is via electroweak gauge and Higgs bosons. In the absence of an ultraviolet-complete particle-physics model, we employ effective field theory to describe the WIMP--SM coupling. We consider both scalars and Dirac fermions as possible dark-matter candidates. Starting with an exhaustive list of operators up to dimension 8, we present detailed calculation of dark-matter annihilations to all possible final states, including gamma gamma, gamma Z, gamma h, ZZ, Zh, W+ W-, hh, and f fbar, and demonstrate the correlations among them. We compute the mass scale of the effective field theory necessary to obtain the correct dark-matter mass density, and well as the resulting photon line signals.