Proca in the sky

Abstract

The standard model of cosmology, the ΛCDM model, describes the evolution of the Universe since the Big Bang with just a few parameters, six in its basic form. Despite being the simplest model, direct late-time measurements of the Hubble constant compared with the early-universe measurements result in the so-called H0 tension. It is claimed that a late time resolution is predestined to fail when different cosmological probes are combined. In this work, we shake the ground of this belief with a very simple model. We show how, in the context of cubic vector Galileon models, the Hubble tension can naturally be relieved using a combination of CMB, BAO and SNe observations without using any prior on H0. The tension can be reduced even further by including the local measurement of the Hubble constant.