# A Robust Method for Treating Astrophysical Mismodeling in Dark Matter Annihilation Searches of Dwarf Spheroidal Galaxies

## TL;DR

This paper introduces a new analysis method that accounts for background mismodeling in dark matter searches using dwarf spheroidal galaxies, resulting in more reliable constraints and detections.

## Contribution

The authors develop an improved joint-likelihood analysis technique that directly addresses background mismodeling effects in dark matter annihilation searches.

## Key findings

- More robust limits on dark matter annihilation cross-section.
- Differences of nearly a factor of two in limits compared to previous analyses.
- Enhanced reliability of dark matter detection claims.

## Abstract

Fermi-LAT observations have strongly constrained dark matter annihilation through the joint-likelihood analysis of dwarf spheroidal galaxies (dSphs). These constraints are expected to be robust because dSphs have measurable dark matter content and produce negligible astrophysical emission. However, each dSph is dim, with a predicted flux that typically falls below the accuracy of the background model. We show that this significantly diminishes the reliability of previous joint-likelihood algorithms, and develop an improved analysis that directly accounts for the effect of background mismodeling. This method produces more robust limits and detections of dark matter in both real and mock data. We calculate improved limits on the dark matter annihilation cross-section, which differ by nearly a factor of two from previous analyses - despite examining identical data.