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.
Highlights
The anomalous magnetic moment of the muon, aμ 1⁄4 ðg − 2Þμ=2, is an accurately measured quantity, which, at the same time, is precisely predicted within the standard model (SM) [1]
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 ðg − 2Þμ 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)
Summary
The anomalous magnetic moment of the muon, aμ 1⁄4 ðg − 2Þμ=2, is an accurately measured quantity, which, at the same time, is precisely predicted within the standard model (SM) [1]. The goal of the present study is to revisit the current constraints on the dominant contribution to ðg − 2Þμ in the MSSM, namely that of the chargino and muon-sneutrino loop, in the light of recent data from both the 8 and 13 TeV runs of the LHC. In the most general scenario, the MSSM parameters relevant for the electroweak searches of our interest in this study are the mass parameters for the bino (M1), wino (M2) and Higgsino (μ), the masses of the lighter (Mτ1) and heavier stau (Mτ2), the mixing angle in the stau sector (θτ), the soft masses of the left-smuon (MμL) and left-selectron (MeL ), and the ratio of the vacuum expectation values of the two Higgs doublets (tan β). We have used the above expressions for Δaμ in the weak eigenstate basis in the subsequent sections, we have checked that using the mass eigenstate basis expressions do not lead to any significant difference for the decoupled right-smuon scenario
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
