Smuon contribution to muon g-2 in Grand Unified supersymmetric theories

Abstract

In GUT-scale constrained (GUTc) supersymmetric (SUSY) models, the mass of smuon \(\tilde{\mu}_1\) is typically heavier than that of stau \(\tilde{\tau}_1\), and stau co-annihilation is a typical annihilation mechanism of dark matter. However, light smuon is more favored by the muon \(g-2\) anomaly, thus smuon-neutralino loop contribution to muon \(g-2\) is usually smaller than that of sneutrino-chargino. Inspired by the latest muon \(g-2\) results, we take the GUTc- Next-to-Minimal Supersymmetric Model (NMSSM) as an example, where the gaugino (Higgs) masses are not unified to the usual parameter \(M_{1/2}\) (\(M_0\)), exploring its possibility of light smuon and its contribution to muon \(g-2\). After complicated calculations and discussions, we conclude that in GUTc-NMSSM the smuon can be lighter than stau. In this light-smuon scenario, the contribution of smuon-neutralino loop to the muon \(g-2\) can be larger than that of the sneutrino-chargino loop. The annihilation mechanisms of dark matter are dominated by multiple slepton or chargino co-annihilation. In our calculations, we consider also other latest related constraints like Higgs data, SUSY searches, dark matter relic density and direct detections, etc.