Closing in on the chargino contribution to the muon g-2 in the MSSM: current LHC constraints

Abstract

We revisit the current LHC constraints on the electroweak-ino sector parameters in the minimal supersymmetric standard model (MSSM) that are relevant to explaining the $(g-2{)}_{\mu }$ anomaly via the dominant chargino and muon sneutrino loop. Since the LHC bounds on electroweak-inos become weaker if they decay via an intermediate stau or a tau sneutrino instead of the first two generation sleptons, we perform a detailed analysis of the scenario with a bino as the lightest supersymmetric particle (LSP) and a light stau as the next-to-lightest one (NLSP). Even in this scenario, the chargino sector parameters in the MSSM that can account for the $(g-2{)}_{\mu }$ anomaly within $1\sigma$ are already found to be significantly constrained by the 8 TeV LHC and the available subset of the 13 TeV LHC limits. We also estimate the current LHC exclusions in the left-smuon (and/or left-selectron) NLSP scenario from multilepton searches, and further combine the constraints from the multi-tau and multi-lepton channels for a mass spectrum in which all three generations of sleptons are lighter than the chargino. In the latter two cases, small corners of the $1\sigma$ favoured region for $(g-2{)}_{\mu }$ are still allowed at present.

Comments: 28 pages, 14 figures; v2: Note added with updated 13 TeV LHC constraints using 36.1 fb^{-1} results, version to appear in Physical Review D