Warped Reheating in Multi-Throat Brane Inflation

TL;DR

This paper analyzes reheating mechanisms in multi-throat brane inflation, showing that KK modes preferentially tunnel to the Standard Model throat and reheat it efficiently, with viability maintained even with additional throats.

Contribution

It provides a detailed quantitative analysis of reheating processes in multi-throat brane inflation, including decay rates and tunneling probabilities within string theory.

Findings

KK modes decay into KK modes rather than gravitons in the inflationary throat.

KK modes tunnel to other throats, including the Standard Model, instead of decaying to gravitons.

Reheating remains viable with multiple throats, especially with small warping.

Abstract

We investigate in some quantitative details the viability of reheating in multi-throat brane inflationary scenarios by estimating and comparing the time scales for the various processes involved. We also calculate within perturbative string theory the decay rate of excited closed strings into KK modes and compare with that of their decay into gravitons; we find that in the inflationary throat the former is preferred. We also find that over a small but reasonable range of parameters of the background geometry, these KK modes will preferably tunnel to another throat (possibly containing the Standard Model) instead of decaying to gravitons due largely to their suppressed coupling to the bulk gravitons. Once tunneled, the same suppressed coupling to the gravitons again allows them to reheat the Standard Model efficiently. We also consider the effects of adding more throats to the system and find that for extra throats with small warping, reheating still seems viable.