Viability of light-boson hairy black holes

Ascertain whether the mass parameter space for ultralight bosons that source scalar/vector hair around black holes will be entirely closed by observations, and whether additional families of hairy rotating black holes remain conceivable and astrophysically relevant.

Background

Ultralight bosons (scalars/vectors) can form clouds around spinning black holes through superradiance, yielding hairy solutions and observable signatures. However, pulsar timing arrays and superradiance constraints are increasingly restricting their mass range.

Determining the fate of this parameter space and the existence of further solutions impacts both particle physics and astrophysics.