Coleman-Weinberg potential in good agreement with WMAP

Abstract

We briefly summarize and update a class of inflationary models from the early eighties based on a quartic (Coleman-Weinberg) potential for a gauge singlet scalar (inflaton) field. For vacuum energy scales comparable to the grand unification scale, the scalar spectral index ${n}_{s}\ensuremath{\simeq}0.94--0.97$, in very good agreement with the WMAP 3-year results. The tensor-to-scalar ratio $r\ensuremath{\lesssim}0.14$ while $\ensuremath{\alpha}\ensuremath{\equiv}\mathrm{d}{n}_{s}/\mathrm{d}\mathrm{ln}k$ is $\ensuremath{\simeq}\ensuremath{-}{10}^{\ensuremath{-}3}$. An $SO(10)$ version naturally explains the observed baryon asymmetry via nonthermal leptogenesis.