Dark Matter Effective Field Theory and an Application to Vector Dark Matter

TL;DR

This paper classifies gauge-invariant interactions involving dark matter particles within effective field theories and applies this framework to a model with vector dark matter, exploring its viability in the freeze-in scenario.

Contribution

It provides a comprehensive classification of dimension-six gauge-invariant interactions for dark matter in EFTs and applies this to a vector dark matter model with stability and phenomenological analysis.

Findings

Vector dark matter model with dimension-six interactions is viable for freeze-in production.

Tree-level matching conditions between SMEFT and LEFT are established.

Dark vector particles can interact with the SM via dimension-six operators.

Abstract

The Standard Model Effective Field Theory (SMEFT) and the Low Energy Effective Field Theory (LEFT) can be extended by adding additional spin 0, 1/2 and 1 dark matter particles which are singlets under the Standard Model (SM) gauge group. We classify all gauge invariant interactions in the Lagrangian up to terms of dimension six, and present the tree-level matching conditions between the two theories at the electroweak scale. The most widely studied dark matter models, such as those based on the Higgs portal or on kinetic mixing between the photon and a dark photon, are based on dimension-four interactions with the SM sector. We consider a model with dark vector particles with a $\mathbb{Z}_2$ symmetry, so that the lightest dark matter particle is stable. The leading interaction with the SM is through dimension-six operators involving two dark vector field-strength tensors and the electromagnetic field-strength tensor. This model is a viable dark matter model in the freeze-in scenario for a wide range of parameters.