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

Abstract

AbstractThe FNAL+BNL measurements for muon $$g-2$$ g - 2 is $$4.2\sigma $$ 4.2 σ above the SM prediction, and the Berkeley $$^{133}$$ 133 Cs measurement for the fine-structure constant $$\alpha _\mathrm{em}$$ α em leads to the SM prediction for electron $$g-2$$ g - 2 which is $$2.4\sigma $$ 2.4 σ above the experimental value. Hence, a joint explanation of both anomalies requires a positive contribution to muon $$g-2$$ g - 2 and a negative contribution to electron $$g-2$$ 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 $$2\sigma $$ 2 σ level, i.e., $$\mu M_1,\mu M_2<0$$ μ M 1 , μ M 2 < 0 , $$m_{L1}, m_{E2}<200$$ m L 1 , m E 2 < 200 GeV, $$m_{L2}$$ m L 2 being much larger than the soft masses of other sleptons, $$|M_1|<125$$ | M 1 | < 125 GeV and $$\mu <400$$ μ < 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 $$g-2$$ g - 2 anomalies at $$2\sigma $$ 2 σ level (the muon $$g-2$$ g - 2 anomaly can be even ameliorated to $$1\sigma $$ 1 σ ).