%0 Journal Article
%T Early-universe constraints on a time-varying fine structure constant
%A P. P. Avelino
%A S. Esposito
%A G. Mangano
%A C. J. A. P. Martins
%A A. Melchiorri
%A G. Miele
%A O. Pisanti
%A G. Rocha
%A P. T. P. Viana
%J Physics
%D 2001
%I arXiv
%R 10.1103/PhysRevD.64.103505
%X Higher-dimensional theories have the remarkable feature of predicting a time (and hence redshift) dependence of the `fundamental' four dimensional constants on cosmological timescales. In this paper we update the bounds on a possible variation of the fine structure constant alpha at the time of BBN (z =10^10) and CMB (z=10^3). Using the recently-released high-resolution CMB anisotropy data and the latest estimates of primordial abundances of 4He and D, we do not find evidence for a varying alpha at more than one-sigma level at either epoch.
%U http://arxiv.org/abs/astro-ph/0102144v4