Phenomenology of wavelike vector dark matter nonminimally coupled to gravity

Abstract

We study three astrophysical/cosmological consequences of nonminimal couplings to gravity in wavelike vector dark matter. In the nonrelativistic limit, the nonminimal coupling with the lowest mass dimension leads to effective self-interactions that affect the mass-radius relation of vector solitons, growth of linear perturbations during structure formation, and the speed of gravitational waves (GWs). Based on the success of cold dark matter on large-scale perturbations and the current limits on GW speed, we constrain the dark matter mass and nonminimal coupling strength to be within the range $|\xi_1| / m^2 \ll 10^{50} \mathrm{eV^{-2}}$ and $-3\times 10^{46} \mathrm{eV^{-2}} \lesssim \xi_2 / m^2 \lesssim 8 \times 10^{48} \mathrm{eV^{-2}}$.