Brane inflation revisited after WMAP five-year results

Abstract

In this paper, we revisit brane inflation models with the WMAPfive-year results. The WMAP five-year data favor a red-tilted powerspectrum of primordial fluctuations at the level of two standarddeviations, which is the same as the WMAP three-year resultqualitatively, but quantitatively the spectral index is slightlygreater than the three-year value. This result can bring impacts onbrane inflation models. According to the WMAP five-year data, wefind that the KKLMMT model can survive at the level of one standarddeviation, and the fine-tuning of the parameter β can bealleviated to a certain extent at the level of two standarddeviations.