Dark matter annihilation through a lepton-specific Higgs boson

It was recently argued by Hooper and Goodenough [arXiv:1010.2752] that the excess gamma-ray emission from within 1^∘{}--2^∘{} 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 a sizable invisible branching fraction. Part of the favored region leads to invisible decays of both of the $CP$-even neutral Higgs states.