Vector Dark Matter in the Fundamental Representation of $SU(2{)}_L$: Sommerfeld Enhancement and Indirect Detection

Abstract

In this work, we study an extension of the Standard Model that includes a new massive vector field in the fundamental representation of $SU(2{)}_L$. The neutral component of this field provides a natural dark matter candidate. We compute the annihilation cross-section including Sommerfeld enhancement and the gamma-ray flux arising from dark matter annihilation. We derive constraints on the model parameter space using current gamma-ray observations and investigate the prospects for future searches. We find that the model exhibits resonances for dark matter masses in the range $2-10$ TeV, whose properties are influenced by the value of the Higgs portal coupling. We show that part of the remaining parameter space can be probed by CTA in the near future.

Comments: This is a completely revised and expanded version of the original paper. New calculations were added. The discussion and conclusions were expanded and reformulated