Inelastic dark matter revives the dark photon explanation of the muon g-2 anomaly

A massive U(1)' gauge boson known as a “dark photon” or A', has long been proposed as a potential explanation for the muon g-2 anomaly. Recently, experimental results have excluded this possibility for a dark photon decaying visibly and invisibly. I revisit this idea and consider a model where A' couples to inelastic dark matter, leading to a semi-visible decay mode. I show that for large mass splittings between the dark sector states this decay mode is enhanced, weakening the invisibly decaying dark photon bounds.