Impacts of the Higgs mass on vacuum stability, running fermion masses, and two-body Higgs decays

The recent results of the ATLAS and CMS experiments indicate 116 GeVMH131 GeV and 115 GeVMH127 GeV, respectively, for the mass of the Higgs boson in the standard model (SM) at the 95% confidence level. In particular, both experiments point to a preferred narrow mass range MH(124⋯126) GeV. We examine the impact of this preliminary result of MH on the SM vacuum stability by using the two-loop renormalization-group equations, and arrive at the cutoff scale ΛVS~4×10¹² GeV (for MH=125 GeV, Mₜ=172.9 GeV, and αₛ(MZ)=0.1184), where the absolute stability of the SM vacuum is lost and some kind of new physics might take effect. We update the values of running lepton and quark masses at some typical energy scales, including the ones characterized by MH, 1 TeV and ΛVS, with the help of the two-loop renormalization-group equations. The branching ratios of some important two-body Higgs decay modes, such as H→bb̄, H→τ⁺τ^-, H→γγ, H→W⁺W^-, and H→ZZ, are also recalculated by inputting the values of relevant particle masses at MH.