The effective field theory of vector-tensor theories

Abstract We investigate a systematic formulation of vector-tensor theories based on the effective field theory (EFT) approach. The input our EFT is that spacetime symmetry spontaneously broken by existence preferred timelike direction in accordance with cosmological principle. After clarifying difference breaking pattern from conventional inflation/dark energy, we find an description around background. This approach not only serves as unified but also highlights universal differences between scalar-tensor and theories. having different patterns are distinguished phenomenological function consistency relations coefficients. study linear perturbations within framework discuss characteristic properties context dark energy. In particular, compute gravitational coupling slip parameter for matter density contrast terms