New constraints on Higgs-portal scalar dark matter

The simplest Higgs-portal dark matter model, in which a real scalar singlet is added to the standard model, has been comprehensively revisited, by taking into account the constraints from perturbativity, electroweak vacuum stability in the early Universe, dark matter direct detection, and Higgs invisible decay at the LHC. We show that the resonant mass region is totally excluded and the high mass region is reduced to a narrow window 1.1 TeV <= m(s) <= 2.55 TeV, which is slightly reduced to 1.1 TeV <= m(s) <= 2.0 TeV if the perturbativity is further imposed. This high mass region can be fully detected by the Xenon1T experiment.