Flavor Phenomenology of Light Dark Vectors

Light dark matter with flavor-violating couplings to fermions may be copiously produced in the laboratory as missing energy from decays of SM particles. Here we study the effective Lagrangian of a light dark vector with generic dipole or vector couplings. We calculate the resulting two-body decay rates of mesons, baryons and leptons as a function of the dark vector mass and show that existing experimental limits probe UV scales as large as $10^{12} \,\mathrm{GeV}$. We also derive the general RGEs in order to constrain the flavor-universal UV scenario, where all flavor violation arises radiatively proportional to the CKM matrix.