Can electron and muon g-2 anomalies be jointly explained in SUSY?

Abstract

The FNAL+BNL measurements for muon g-2 is 4.2sigma above the SM prediction, and the Berkeley ^{133}Cs measurement for the fine-structure constant alpha _mathrm{em} leads to the SM prediction for electron g-2 which is 2.4sigma above the experimental value. Hence, a joint explanation of both anomalies requires a positive contribution to muon g-2 and a negative contribution to electron g-2, which is rather challenging. In this work we explore the possibility of such a joint explanation in the minimal supersymmetric standard model (MSSM). Assuming no universality between smuon and selectron soft masses, we find out a part of parameter space for a joint explanation at 2sigma level, i.e., mu M_1,mu M_2<0, m_{L1}, m_{E2}<200 GeV, m_{L2} being much larger than the soft masses of other sleptons, |M_1|<125 GeV and mu <400 GeV. This part of parameter space can survive LHC and LEP constraints, but gives an over-abundance for dark matter if the bino-like lightest neutralino is assumed to be the dark matter candidate. With the assumption that the dark matter candidate is a superWIMP (say a pseudo-goldstino in multi-sector SUSY breaking scenarios, whose mass can be as light as GeV and produced from the late-decay of the thermally freeze-out lightest neutralino), the dark matter problem can be avoided. So, we conclude that the MSSM may give a joint explanation for the muon and electron g-2 anomalies at 2sigma level (the muon g-2 anomaly can be even ameliorated to 1sigma ).