Lookback time as a test for brane cosmology

Abstract

The observed late-time acceleration of the Universe may be the result of unknown physical processes involving either modifications of gravitation theory or the existence of new fields in high energy physics. In the former case, such modifications are usually related to the possible existence of extra dimensions (which is also required by unification theories), giving rise to the so-called brane cosmology. In this paper we investigate the viability of this idea by considering a particular class of brane scenarios in which a large scale modification of gravity arises due to a gravitational \emph{leakage} into extra dimensions. To this end, differently from other recent analyses, we combine \emph{orthogonal} age and distance measurements at intermediary and high redshifts. We use observations of the lookback time to galaxy clusters, indirect estimates of the age of the Universe from the most recent Large-Scale Structure (LSS) and Cosmic Microwave Background (CMB) data, along with the recent detection of the baryon acoustic oscillations at $z = 0.35$. In agreement with other recent analyses we show that, although compatible with these age and distance measurements, a spatially closed scenario is largely favoured by the current observational data. By restricting our analysis to a spatially flat universe, we also find that the standard $\Lambda$CDM model is favoured over the particular braneworld scenario here investigated.