Dark photon superradiance quenched by dark matter

TL;DR

This paper demonstrates that superradiance bounds on dark photons are not universally robust and can be bypassed if dark photons interact with a larger dark sector containing dark matter particles.

Contribution

It reveals that superradiance constraints on dark photons can be invalidated by extensions involving dark matter coupling, challenging previous assumptions of model independence.

Findings

Superradiance bounds can be circumvented with dark sector extensions.

Dark matter coupling affects the robustness of superradiance constraints.

Model extensions can invalidate previous bounds on dark photons.

Abstract

Black-hole superradiance has been used to place very strong bounds on a variety of models of ultralight bosons such as axions, new light scalars, and dark photons. It is common lore to believe that superradiance bounds are broadly model independent and therefore pretty robust. In this work we show however that superradiance bounds on dark photons can be challenged by simple, compelling extensions of the minimal model. In particular, if the dark photon populates a larger dark sector and couples to dark fermions playing the role of dark matter, then superradiance bounds can easily be circumvented, depending on the mass and (dark) charge of the dark matter.