Measuring smuon-selectron mass splitting at the CERN LHC and patterns of supersymmetry breaking

Abstract

With sufficient data, CERN LHC experiments can constrain the smuon-selectron mass splitting through differences in the dielectron and dimuon edges from supersymmetry (SUSY) cascade decays. We study the sensitivity of the LHC to this mass splitting, which within minimal supergravity may be constrained down to O(10-4) for 30 fb-1 of integrated luminosity. Over substantial regions of SUSY breaking parameter space the fractional edge splitting can be significantly enhanced over the fractional mass splitting. Within models where the selectron and smuon are constrained to be universal at a high scale, edge splittings up to a few percent may be induced by renormalization group effects and may be significantly discriminated from zero. The edge splitting provides important information about high-scale SUSY breaking terms and should be included in any fit of LHC data to high-scale models.