Slow-roll reconstruction for running spectral index

Abstract

We not only reconstruct the slow-roll parameters for fit to the running spectral index from WMAP three-year data in the usual slow-roll inflation model and noncommutative inflation model, but also investigate the evolution of these slow-roll parameters. Requiring slow-roll inflation lasts more than 20 e-folds after CMB scales leave the horizon suggests that the potential at the last stage of inflation takes the form $V(\varphi )=V_0(1+\frac{{\eta }_c}{2}\frac{(\varphi -{\varphi }_c{)}^2}{M_p^2})$, where ${\eta }_c$ is a constant. A natural mechanism to end inflation at $\varphi ={\varphi }_c$ is hybrid type inflation.

Comments: 18 pages, 7 figures; refs added, version for publication in PRD