Proca in the sky

TL;DR

This paper demonstrates that cubic vector Galileon models can naturally resolve the Hubble tension by combining multiple cosmological observations without prior assumptions on H0.

Contribution

It introduces a simple cubic vector Galileon model that alleviates the H0 tension using existing cosmological data, challenging the belief that late-time solutions are doomed to fail.

Findings

Hubble tension can be reduced with the model

Combining CMB, BAO, and SNe data is effective

Including local H0 measurements further alleviates tension

Abstract

The standard model of cosmology, the $\Lambda$CDM 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 $H_0$ 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 $H_0$ . The tension can be reduced even further by including the local measurement of the Hubble constant.