The $\textit{Fermi}$-LAT gamma-ray excess at the Galactic Center in the singlet-doublet fermion dark matter model

TL;DR

This paper investigates the singlet-doublet fermion dark matter model's ability to explain the Fermi-LAT gamma-ray excess at the Galactic Center, analyzing its compatibility with current and future detection experiments.

Contribution

It identifies parameter regions in the SDFDM model that fit the gamma-ray excess and assesses their testability with upcoming experimental data.

Findings

DM particles near 99 GeV and 173-190 GeV fit the GCE.

Future experiments like LZ and XENON-1T can exclude much of the parameter space.

LUX data is already probing the best-fit regions.

Abstract

The singlet-doublet fermion dark matter model (SDFDM) provides a good DM candidate as well as the possibility of generating neutrino masses radiatively. The search and identification of DM requires the combined effort of both indirect and direct DM detection experiments in addition to the LHC. Remarkably, an excess of GeV gamma rays from the Galactic Center (GCE) has been measured with the \textit{Fermi} Large Area Telescope (LAT) which appears to be robust with respect to changes in the diffuse galactic background modeling. Although several astrophysical explanations have been proposed, DM remains a simple and well motivated alternative. In this work, we examine the sensitivities of dark matter searches in the SDFDM scenario using $\textit{Fermi}$-LAT, CTA, IceCube/DeepCore, LUX, PICO and LHC with an emphasis on exploring the regions of the parameter space that can account for the GCE. We find that DM particles present in this model with masses close to $\sim 99$ GeV and $\sim (173-190)$ GeV annihilating predominantly into the $W^+W^-$ channel and $t\bar{t}$ channel respectively, provide an acceptable fit to the GCE while being consistent with different current experimental bounds. We also find that much of the obtained parameter space can be ruled out by future direct search experiments like LZ and XENON-1T, in case of null results by these detectors. Interestingly, we show that the most recent data by LUX is starting to probe the best fit region in the SDFDM model.