Light Stau Phenomenology and the Higgs \gamma\gamma Rate

TL;DR

This paper explores how light staus with large mixing in supersymmetric models could explain the enhanced Higgs to gamma gamma rate observed at the LHC, analyzing phenomenology, constraints, and collider signatures.

Contribution

It provides a detailed phenomenological analysis of light staus with large mixing as a source of Higgs gamma gamma enhancement, including collider prospects and consistency with experimental data.

Findings

Light staus can enhance the Higgs gamma gamma decay rate.

Collider signatures of light staus are detectable at 8 TeV and 14 TeV LHC.

Parameter space consistent with electroweak precision tests and dark matter constraints.

Abstract

Recently, an excess of events consistent with a Higgs boson with mass of about 125 GeV was reported by the CMS and ATLAS experiments. This Higgs boson mass is consistent with the values that may be obtained in minimal supersymmetric extensions of the Standard Model (SM), with both stop masses less than a TeV and large mixing. The apparently enhanced photon production rate associated with this potential Higgs signal may be the result of light staus with large mixing. Large stau mixing and large coupling of the staus to the SM-like Higgs boson may be obtained for large values of tan \beta, and moderate to large values of the Higgsino mass parameter, \mu. We study the phenomenological properties of this scenario, including precision electroweak data, the muon anomalous magnetic moment, Dark Matter, and the evolution of the soft supersymmetry-breaking parameters to high energies. We also analyze the possible collider signatures of light third generation sleptons and demonstrate that it is possible to find evidence of their production at the 8 TeV and the 14 TeV LHC. The most promising channel is stau and tau sneutrino associated production, with the sneutrino decaying into a W boson plus a light stau.