Dark matter annihilation through a lepton-specific Higgs boson

TL;DR

This paper proposes a model where a lepton-specific Higgs boson mediates dark matter annihilation, explaining gamma ray excesses near the galactic center with a natural extension of the two-Higgs-doublet framework.

Contribution

It introduces a lepton-specific two-Higgs-doublet model with a stable singlet scalar dark matter candidate that naturally produces the observed gamma ray excess.

Findings

A light Higgs state below 200 GeV with enhanced lepton couplings is favored.

The model predicts invisible decays of CP-even neutral Higgs states.

The scenario aligns with gamma ray observations from the galactic center.

Abstract

It was recently argued by Hooper and Goodenough [arXiv:1010.2752] that the excess gamma ray emission from within 1-2 degrees of the galactic center can be well-described by annihilation of ~8 GeV dark matter particles into tau pairs. I show that such a dark matter signal can be obtained naturally in the lepton-specific two-Higgs-doublet model extended by a stable singlet scalar dark matter candidate. The favored parameter region prefers a light Higgs state (below 200 GeV) with enhanced couplings to leptons and sizable invisible branching fraction. Part of the favored region leads to invisible decays of both of the CP-even neutral Higgs states.