Revisiting a vector-tensor theory of gravitation

Abstract

A certain vector-tensor theory of gravitation has been recently studied. In this theory, the zero-order energy density of the vector field could play the role of dark energy. In such a case, the question is: could the theory explain current cosmological observations as well as the so-called concordance model? Previous papers on the subject only consider a reduced number of current observations. We consider a wider set of observations including supernovae of type Ia, cosmic microwave background anisotropies, and the power spectrum of the energy density fluctuations. Results imply that, for negligible scalar perturbations of the vector field, the theory does not work.