Light stau phenomenology and the Higgs γγ rate

Abstract

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 β and moderate to large values of the Higgsino mass parameter, µ. 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.

NSUSY fits

“…We will not consider light staus (τ ± ), which can also modify the Higgs decays to photons, see refs. [8,9] for recent studies. We neglect these states as we assume a moderate value of tan β O(10), for whichτ ± effects are negligible compared to the stop contribution.…”

“…[25] in the limit where gluino effects and the effect of squark mixing was neglected. 8 This approach also neglects running that would sum large logs if a two stage matching was employed, integrating out each stop eigenstate in sequence. 9 Whether one integrates out the stops and matches onto the local operator approximation or not, there is a relationship between the NP effects on σ gg→h and σ h→γγ that 7 Here we have neglected D term contributions, although we retain the effect of D terms in some of the numerical results presented.…”

Beyond Standard Model Collider Phenomenology of Higgs Physics and Supersymmetry

“…There has been much previous literature which has explored the Higgs sector in a variety of SUSY scenarios, such as the MSSM [80][81][82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99] (also the constrained version [100][101][102][103][104][105][106]), Next-to-MSSM [107][108][109][110][111][112][113][114] and (B-L)SSM [115][116][117][118], including scenarios with light charginos [119], staus [88,120] and stops [88].…”

“…Moreover, light charginos could only alter the h → γγ decay, which is qualitatively similar to the effect from the light staus. However the maximum effect of light staus is much larger [120], and is considered in this study in great detail, together with the light sbottom and light stop scenarios. Therefore, in this study we concentrate on scenario (4) in which sizeable MSSM contributions via scalar loops are possible.…”

MSSM electroweak baryogenesis and LHC data

“…For tan β ≤ 15 light staus do not essentially modify the Higgs phenomenology presented in this paper. However in the presence of cancellations in the EDMs chargino-neutralino contributions larger values of tan β (tan β ∼ 60) would be allowed and consequently light staus would enhance the diphoton Higgs decay rate [67,68] as well as the baryon asymmetry production [69]. We leave this possibility for future studies.…”