Searching for vector dark matter via Higgs portal at the LHC

Abstract

A Higgs portal dark matter model for explaining the gamma-ray excess from the galactic center can be realized with the extension of local $SU(2)_X$ gauge symmetry with one quadruplet. Due to the residual $Z_3$ discrete symmetry of $SU(2)_X$, the new gauge bosons are the stable dark matter candidates. Due to the mixture of the standard model Higgs doublet and the introduced quadruplet, dark matter could annihilate into the standard model particles through the Higgs portal and new scalar portal. We study the discovery significance of the vector dark matter at the Large Hadron Collider. The involved parameters are consistent with the constraints from relic density and direct detection and with the data of the galactic center gamma-ray excess. With $\sqrt{s}=14$ TeV and luminosities of $100$ and $300$ fb$^{-1}$, we find that a discovery significance of $S/\sqrt{B}=5$ can be easily reached if the production of dark matter is through the invisible decays of the Higgs boson and a new scalar boson.