Can brane cosmology with a vanishing Λ explain the observations?

Abstract

A plethora of models of the universe have been proposed in recent years claiming that the present universe is accelerating, being driven by some hypothetical source with negative pressure collectively known as dark energy, which do not appear to resemble any known form of matter tested in the laboratory. These models are motivated by the high-redshift supernovae (SN) Ia observations. Though low-density models, without dark energy, also appear to fit the SN Ia data reasonably well, however, they are ruled out by the cosmic microwave background (CMB) observations.In this paper, we present a warped brane model with an additional surface term of brane curvature scalar in the action. This results in shifting the dynamical curvature of the model from its geometrical counterpart, which creates profound consequences. Even for Λ = 0, the low-energy decelerating model successfully explains the observed locations of the peaks in the angular power spectrum of CMB. This model also fits the high-redshift SN Ia observations, taken together with the recently observed SN 1997ff at z ≈ 1.7, very well. Additionally, it also fits the data on the angular size and redshift of the compact radio sources very well.