Implications for constrained supersymmetry of combined H.E.S.S. observations of dwarf galaxies, the Galactic halo and the Galactic Centre

TL;DR

This study uses H.E.S.S. gamma-ray data from dwarf galaxies, the Galactic halo, and the Galactic Centre to constrain supersymmetric dark matter models, revealing strong limits on coannihilation scenarios within the CMSSM.

Contribution

It performs detailed scans of the CMSSM parameter space incorporating realistic gamma-ray spectra and combines multiple observational data sets for robust constraints.

Findings

Dwarf galaxy observations strongly disfavor coannihilation regions.

Constraints on models with large annihilation cross-sections are significant.

Galactic Centre data show no effect due to complex gamma-ray backgrounds.

Abstract

In order to place limits on dark matter (DM) properties using $\gamma$-ray observations, previous analyses have often assumed a very simple parametrisation of the $\gamma$-ray annihilation yield; typically, it has been assumed that annihilation proceeds through a single channel only. In realistic DM models, annihilation may occur into many different final states, making this quite a rough ansatz. With additional processes like virtual internal bremsstrahlung and final state radiation, this ansatz becomes even more incorrect, and the need for scans of explicit model parameter spaces becomes clear. Here we present scans of the parameter space of the Constrained Minimal Supersymmetric Standard Model (CMSSM), considering $\gamma$-ray spectra from three dwarf galaxies, the Galactic Centre region and the broader Galactic halo, as obtained with the High-Energy Stereoscopic System (H.E.S.S.). We present a series of likelihood scans combining the H.E.S.S. data with other experimental results. We show that observations of the Sagittarius, Carina and Sculptor dwarf galaxies disfavour the coannihilation region of the CMSSM and models with large annihilation cross-sections. This is true even under reasonable assumptions about the DM density profiles, and constitutes the strongest constraint to date on coannihilation models within the CMSSM. The Galactic halo has a similar, but weaker, effect. The Galactic Centre search is complicated by a strong (unknown) $\gamma$-ray source, and we see no effect on the CMSSM parameter space when assuming a realistic Galactic Centre DM density profile.