Indirect Detection Constraints on s and t Channel Simplified Models of Dark Matter

TL;DR

This paper extends gamma-ray observational constraints on dark matter annihilation by analyzing multiple final states in simplified models, providing limits on dark matter and mediator parameters, and comparing with effective field theory approaches.

Contribution

It introduces a joint-likelihood analysis for multi-final state dark matter annihilation in simplified models, enhancing the interpretation of gamma-ray data.

Findings

Constraints on dark matter mass and mediator parameters derived.

Comparison between simplified models and EFT contact interactions.

Enhanced limits from combined dwarf galaxy observations.

Abstract

Recent Fermi-LAT observations of dwarf spheroidal galaxies in the Milky Way have placed strong limits on the gamma-ray flux from dark matter annihilation. In order to produce the strongest limit on the dark matter annihilation cross-section, the observations of each dwarf galaxy have typically been "stacked" in a joint-likelihood analysis, utilizing optical observations to constrain the dark matter density profile in each dwarf. These limits have typically been computed only for singular annihilation final states, such as $b\bar{b}$ or $\tau^+\tau^-$. In this paper, we generalize this approach by producing an independent joint-likelihood analysis to set constraints on models where the dark matter particle annihilates to multiple final state fermions. We interpret these results in the context of the most popular simplified models, including those with s- and t-channel dark matter annihilation through scalar and vector mediators. We present our results as constraints on the minimum dark matter mass and the mediator sector parameters. Additionally, we compare our simplified model results to those of Effective Field Theory contact interactions in the high-mass limit.