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

TL;DR

This paper investigates how the Higgs boson mass influences the stability of the Standard Model vacuum, updates running fermion masses at various energy scales, and recalculates key Higgs decay branching ratios based on recent experimental data.

Contribution

It provides a detailed analysis of vacuum stability considering the Higgs mass range and updates fermion masses and decay rates using two-loop RGEs and current experimental inputs.

Findings

Vacuum stability cutoff scale around 4 x 10^{12} GeV for M_H = 125 GeV

Updated running fermion masses at multiple energy scales

Recalculated Higgs decay branching ratios with current parameters

Abstract

The latest results of the ATLAS and CMS experiments indicate 116 GeV \lesssim M_H \lesssim 131 GeV and 115 GeV \lesssim M_H \lesssim 127 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 M_H \simeq (124 ... 126) GeV. We examine the impact of this preliminary result of M_H on the SM vacuum stability by using the two-loop renormalization-group equations (RGEs), and arrive at the cutoff scale \Lambda_VS \sim 4 \times 10^{12} GeV (for M_H = 125 GeV, M_t = 172.9 GeV and \alpha_s(M_Z) = 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 M_H, 1 TeV and \Lambda_VS, with the help of the two-loop RGEs. The branching ratios of some important two-body Higgs decay modes, such as H \to b\bar{b}, H \to \tau^+ \tau^-, H\to \gamma\gamma, H\to W^+ W^- and H \to Z Z, are also recalculated by inputting the values of relevant particle masses at M_H.