Detectable dark photon dark matter

Dark photons are excellent dark matter candidates and offer compelling experimental targets. However, recently it has been shown that the simplest production scenarios (e.g. inflationary production and axion-dark photon conversion) lead to the formation of topological defects rather than nonrelativistic dark matter, substantially restricting the viable parameter space. I will first explain how defect formation constrains dark photon production on a model-independent basis. Then I will present a construction that avoids these constraints by delaying production until very late times, re-opening a large part of the experimentally accessible parameter space and offering additional cosmological signatures.