Searching SUSY Leptonic Partner at the CERN LHC

Motivated by the observed excess of the di-photon signal in Higgs searches, $σ_{γγ}/σ_{\rm SM}\simeq 1.5$, we argue that models with enhanced $Γ(h\to γγ)$ alone are the most favorable scenarios when the latest LHC/Tevatron results are all taken into account. We study the phenomenology of a supersymmetric scenario of light stau first proposed by \textit{Carena et. al. \cite{carlos}} that predicts a 125 GeV SM-like Higgs boson with enhanced diphoton decay through light stau loops. Since it is extremely challenging to search the Drell-Yan stau pair at the LHC due to the small production rate, we focus on the parameter space with enhanced production of inclusive stau pairs, in particular, via $b\bar{b}$ fusion or gaugino pairs. We study its phenomenology in both pure leptonic tau $τ^\pm_\ell$ channels and hadronic tau tagged $τ_h$ channels. We find the same-sign dilepton from $\tildeχ^\pm_1 \tildeχ^0_2 \to τ^\pm_\ell τ^\pm_\ell+X$ may significantly improve the discovery potential with even 7--8 TeV LHC of ${\cal O}(30 \text{fb}^{-1})$ data. In the case of hadronic tau pair, we use the final state $j+τ_h τ_h +\cancel{E}_T$ to search and find that even with the most optimistic region of $M_2\sim 200-300$ GeV, it requires at least 50 fb$^{-1}$ data of 14 TeV LHC to reach a significance of 3.5 $σ$. Therefore, we conclude it is difficult to claim discovery only through hadronic tau based on the data by the 2012 shut-down. 5 $σ$ reach for our most optimistic region then requires 100 fb$^{-1}$ data with 14 TeV running.

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