The Fate of Massive F-Strings

TL;DR

This paper calculates decay rates of massive string states in different string theories and explores implications for brane-inflation models, revealing suppression or enhancement depending on the final string states.

Contribution

It provides the first detailed semi-inclusive decay rate calculations for average string states in both bosonic and superstring theories, with applications to brane-inflation scenarios.

Findings

Decay rate is suppressed when all final strings are massive.

Decay rate is enhanced if one final string is massless.

Implications challenge certain brane-inflation models.

Abstract

We calculate the semi-inclusive decay rate of an average string state with compactification both in the bosonic string theory and in the superstring theory. We also apply this calculation to a brane-inflation model in a warped geometry and find that the decay rate is greatly suppressed if final strings are all massive and enhanced with one final string massless, which may pose a challenge to this class of models.