Higgs portal vector dark matter for<i>GeV</i>scale γ-ray excess from galactic center

Abstract

We show that the $\\mathinner{\\mathrm{GeV}}$ scale $\\gamma$-ray excess from\nthe direction of the Galactic Center can be naturally explained by the pair\nannihilation of Abelian vector dark matter (VDM) into a pair of dark Higgs\nbosons $VV \\rightarrow \\phi \\phi$, followed by the subsequent decay of $\\phi$\ninto $\\phi \\rightarrow b\\bar{b} , \\tau \\bar{\\tau} $. All the processes are\ndescribed by a renormalizable VDM model with the Higgs portal, which is\nnaturally flavor-dependent. Some parameter space of this scenario can be tested\nat the near future direct dark matter search experiments such as LUX and\nXENON1T.\n