Leptonic ALP portal to the dark sector

We discuss the leptonic axionlike particle (ALP) portal as a simple scenario that connects observed discrepancies in anomalous magnetic moments to the dark matter relic abundance. In this framework an axionlike particle in the multi-MeV range couples to SM leptons and a dark matter (DM) fermion, with mass above the ALP mass but below 1 GeV. The ALP contributes to $(g−2)_μ$ and $(g−2)_e$ dominantly through two-loop Barr-Zee diagrams, while the DM abundance is generated by $p$-wave annihilation to ALP pairs. Constraints from beam-dump experiments, colliders, and cosmic microwave background probes are very stringent, and restrict the viable parameter space to a rather narrow region that will be tested in the near future.