Shedding light on dark matter with recent muon (g − 2) and Higgs exotic decay measurements

Recently, we have witnessed two hints of physics beyond the standard model: a 3.3σ local excess ( $$ {M}_{A_0} $$ = 52 GeV) in the search for H0 → A0A0 → b $$ \overline{b} $$ μ+μ− and a 4.2σ deviation from the SM prediction in the (g − 2)μ measurement. The first excess was found by the ATLAS collaboration using 139 fb−1 data at $$ \sqrt{s} $$ = 13 TeV. The second deviation is a combination of the results from the Brookhaven E821 and the recently reported Fermilab E989 experiment. We attempt to explain these deviations in terms of a renormalizable simplified dark matter model. Inspired by the null signal result from dark matter (DM) direct detection, we interpret the possible new particle, A0, as a pseudoscalar mediator connecting DM and the standard model. On the other hand, a new vector-like muon lepton can explain these two excesses at the same time while contributing to the DM phenomenology.