Brane inflation revisited after WMAP five-year results

TL;DR

This paper analyzes how the five-year WMAP data impacts brane inflation models, showing that some models like KKLMMT remain viable with less fine-tuning, due to the observed spectral index.

Contribution

It revisits brane inflation models in light of WMAP five-year data, demonstrating the models' viability and reduced fine-tuning requirements.

Findings

KKLMMT model can survive at one standard deviation

Spectral index slightly greater than three-year value

Fine-tuning of parameter β can be alleviated

Abstract

In this paper, we revisit brane inflation models with the WMAP five-year results. The WMAP five-year data favor a red-tilted power spectrum of primordial fluctuations at the level of two standard deviations, which is the same as the WMAP three-year result qualitatively, but quantitatively the spectral index is slightly greater than the three-year value. This result can bring impacts on brane inflation models. According to the WMAP five-year data, we find that the KKLMMT model can survive at the level of one standard deviation, and the fine-tuning of the parameter $\beta$ can be alleviated to a certain extent at the level of two standard deviations.