Connecting Dark Matter Annihilation to the Vertex Functions of Standard Model Fermions

TL;DR

This paper links dark matter annihilation processes to Standard Model fermion vertex functions, proposing that future collider measurements could significantly improve constraints on dark matter properties beyond current methods.

Contribution

It introduces a novel approach connecting dark matter annihilation to fermion vertex corrections, enabling potential collider-based constraints.

Findings

Dark matter annihilation cross sections relate to fermion charge form factor corrections.

Future colliders could improve dark matter constraints by orders of magnitude.

Current collider data are insufficient for strong dark matter constraints.

Abstract

We consider scenarios in which dark matter is a Majorana fermion which couples to Standard Model fermions through the exchange of charged mediating particles. The matrix elements for various dark matter annihilation processes are then related to one-loop corrections to the fermion-photon vertex, where dark matter and the charged mediators run in the loop. In particular, in the limit where Standard Model fermion helicity mixing is suppressed, the cross section for dark matter annihilation to various final states is related to corrections to the Standard Model fermion charge form factor. These corrections can be extracted in a gauge-invariant manner from collider cross sections. Although current measurements from colliders are not precise enough to provide useful constraints on dark matter annihilation, improved measurements at future experiments, such as the International Linear Collider, could improve these constraints by several orders of magnitude, allowing them to surpass the limits obtainable by direct observation.