Abstract
Abstract The lack of observation of superpartners at the Large Hadron Collider so far has led to a renewed interest in supersymmetric models with R-parity violation (RPV). In particular, imposing the Minimal Flavor Violation (MFV) hypothesis on a general RPV model leads to a realistic and predictive framework. Naturalness suggests that stops and gluinos should appear at or below the TeV mass scale. We consider a simplified model with these two particles and MFV couplings. The model predicts a significant rate of events with same-sign dileptons and b-jets. We re-analyze a recent CMS search in this channel and show that the current lower bound on the gluino mass is about 800 GeV at 95% confidence level, with only a weak dependence on the stop mass as long as the gluino can decay to an on-shell top-stop pair. We also discuss how this search can be further optimized for the RPV/MFV scenario, using the fact that MFV stop decays often result in jets with large invariant mass. With the proposed improvements, we estimate that gluino masses of up to about 1.4 TeV can be probed at the 14 TeV LHC with a 100 fb−1 data set.
Highlights
JHEP04(2013)077 suppresses dangerous operators such as those that induce proton decay
We re-analyze a recent CMS search in this channel and show that the current lower bound on the gluino mass is about 800 GeV at 95% confidence level, with only a weak dependence on the stop mass as long as the gluino can decay to an on-shell top-stop pair
If each top decays leptonically, the final state will contain two same-sign leptons: e±e±, μ±μ±, or e±μ±. Such “same-sign dilepton” (SSDL) events are very rare in the SM, and the SSDL signature already plays a prominent role in the LHC SUSY searches
Summary
Both CMS and ATLAS perform searches for the SSDL signature, accompanied by MET and jets (with or without b-tag requirement), as part of their standard search strategy to look for R-parity conserving (RPC) SUSY with light gluinos and stops. The cross section, acceptance and efficiency are used to compute the number of expected signal events at each (mg, mt) point Comparing this number with the background prediction and data provided by CMS and using the CLs method [27, 28] yields the expected 95% confidence level (CL) exclusion. The results of this analysis are summarized by figure 1, which shows the 95% CL exclusion contours from the four most sensitive signal regions. The remaining differences are accounted for by the slightly higher integrated luminosity of the CMS search, as well as the additional requirement of b-tagged jets imposed by CMS
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