Observing the dark scalar doublet and its impact on the standard-model Higgs boson at colliders

Abstract

If the standard model of particle interactions is extended to include a second scalar doublet $[{H}^{+},({H}^{0}+i{A}^{0})/\sqrt{2}]$, which is odd under an unbroken ${Z}_{2}$ discrete symmetry, it may be called the dark scalar doublet, because its lightest neutral member, say ${H}^{0}$, is one possible component for the dark matter of the Universe. We discuss the general phenomenology of the four particles of this doublet, without assuming that ${H}^{0}$ is the dominant source of dark matter. We also consider the impact of this dark scalar doublet on the phenomenology of the standard-model Higgs boson $h$.