From New to Large Field Inflation: Comparison with WMAP3

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=0.94-0.97, in very good agreement with the WMAP three year results. The tensor to scalar ratio r<~0.14 while alpha=dn_s/d ln k=~-10^-3. For vacuum energy scales >~10^16 GeV, the inflationary scenario switches from `new' to `large-field' (V\proptoϕ^2) inflation. An SO(10) version naturally explains the observed baryon asymmetry via non-thermal leptogenesis.

7 pages, 4 figures, 1 table. Based on a talk given by Q. Shafi at the 2nd International Conference on The Dark Side of the Universe (DSU 2006), Madrid (Spain), 20-24 June 2006