Dark Higgs Channel for FERMI GeV $\gamma$-ray Excess

TL;DR

This paper explores a dark matter model involving a dark Higgs that explains the Fermi GeV gamma-ray excess through dark matter annihilation, highlighting indirect detection as a key probe of dark sectors.

Contribution

It introduces a dark Higgs channel for dark matter annihilation that fits gamma-ray excess data and discusses its implications for dark matter models with dark gauge symmetries.

Findings

Best-fit dark matter mass around 95 GeV

Dark Higgs mass approximately 87 GeV

Annihilation cross-section near 4.0×10^{-26} cm^3/s

Abstract

Dark Higgs is very generic in dark matter models where DM is stabilized by some spontaneously broken dark gauge symmetries. Motivated by the FERMI observation of $\sim$GeV scale $\gamma$-ray excess from the galactic center (GC), we investigate a scenario that a pair of dark matter $X$ annihilates into a pair of dark Higgs $H_2$, which subsequently decays into standard model particles through its mixing with SM Higgs boson. Besides the two-body decay of $H_2$, we also include multibody decay channels of the dark Higgs. We find that the best-fit point is around $M_X\simeq 95.0$GeV, $M_{H_2}\simeq 86.7$GeV, $\langle \sigma v\rangle\simeq 4.0\times 10^{-26}\textrm{cm}^3\textrm{/s}$ and gives a p-value $\simeq 0.40$. Implication of this result is described in the context of dark matter models with dark gauge symmetries. Since such a dark Higgs boson is very difficult to produce at colliders, indirect DM detections of cosmic $\gamma$-rays could be an important probe of dark sectors, complementary to collider searches.