Impact of LSP Character on Slepton Reach at the LHC

Impact of LSP Character on Slepton Reach at the LHC Jonathan Eckel1∗, Michael J. Ramsey-Musolf2,3†, William Shepherd4,5‡, Shufang Su1§ 1 Department of Physics, University of Arizona, Tucson, AZ 85721 2 Amherst Center for Fundamental Interactions, Department of Physics University of Massachusetts-Amherst, Amherst, MA 01003 3 Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA 91125 4 Department of Physics, University of California Santa Cruz, Santa Cruz, CA 95064 5 Santa Cruz Institute for Particle Physics, Santa Cruz, CA 95064 Abstract Searches for supersymmetry at the Large Hadron Collider (LHC) have significantly constrained the parameter space associated with colored superpartners, whereas the constraints on color-singlet superpartners are considerably less severe. In this study, we investigate the dependence of slepton decay branching fractions on the nature of the lightest supersymmetric particle (LSP). In particular, in the Higgsino-like LSP scenarios, both decay branching fractions of ̃̀L and ν̃` depend strongly on the sign and value of M1/M2, which has strong implications for the reach of dilepton plus ET searches for slepton pair production. We extend the experimental results for same flavor, opposite sign dilepton plus ET searches at the 8 TeV LHC to various LSP scenarios. We find that the LHC bounds on sleptons are strongly enhanced for a non-Bino-like LSP: the 95% C.L. limit for m ̃̀ L extends from 300 GeV for a Bino-like LSP to about 370 GeV for a Wino-like LSP. The bound for ̃̀L with a Higgsino-like LSP is the strongest (∼ 490 GeV) for M1/M2 ∼ − tan2 θW and is the weakest (∼ 220 GeV) for M1/M2 ∼ tan2 θW . We also calculate prospective slepton search reaches at the 14 TeV LHC. With 100 fb−1 integrated luminosity, the projected 95% C.L. mass reach for the left-handed slepton varies from 550 (670) GeV for a Bino-like (Wino-like) LSP to 900 (390) GeV for a Higgsino-like LSP under the most optimistic (pessimistic) scenario. The reach for the right-handed slepton is about 440 GeV. The corresponding 5σ discovery sensitivity is about 100 GeV smaller. For 300 fb−1 integrated luminosity, the reach is about 50 − 100 GeV higher.