Current experimental constraints on the lightest Higgs boson mass in the constrained MSSM

TL;DR

This paper analyzes experimental constraints on the lightest Higgs boson mass within the constrained MSSM, finding an upper bound around 124-126 GeV and implications for collider signals and superpartner masses.

Contribution

It provides the first comprehensive analysis combining collider, dark matter, and flavor constraints to bound the Higgs mass in the constrained MSSM.

Findings

Higgs mass upper bound is about 124-126 GeV.

Di-photon Higgs signal is suppressed compared to the SM.

Top-squark mass lower bound increases with Higgs mass, reaching 600 GeV at 124 GeV.

Abstract

We examine the parameter space of the constrained MSSM by considering various experimental constraints. For the dark matter sector, we require the neutralino dark matter to account for the relic density measured by the WMAP and satisfy the XENON limits on its scattering rate with the nucleon. For the collider constraints, we consider all relevant direct and indirect limits from LEP, Tevatron and LHC as well as the muon anomalous magnetic moment. Especially, for the limits from B_s->\mu^+\mu^-, we either directly consider its branching ratio with the latest LHC data or alternatively consider the double ratio of the purely leptonic decays defined by [Br(B_s->\mu^+\mu^-)/Br(B_u->\tau \nu_\tau)]/[Br(D_s->\tau \nu_\tau)/Br(D->\tau \mu_\tau)]. We find that under these constraints, the mass of the lightest Higgs boson (h) in both the CMSSM and the NUHM2 is upper bounded by about 124 GeV (126 GeV) before (after) considering its theoretical uncertainty. We also find that for these models the di-photon Higgs signal at the LHC is suppressed relative to the SM prediction, and that the lower bound of the top-squark mass goes up with m_h, reaching 600 GeV for m_h=124 GeV.