Moduli-Induced Gravitino Problem

TL;DR

This work investigates the cosmological moduli problem by studying a modulus decay in detail and finds that the branching ratio of the gravitino production is generically of O(0.01-1), which causes anothercosmological disaster.

Abstract

We investigate the cosmological moduli problem by studying a modulus decay in detail and find that the branching ratio of the gravitino production is generically of O(0.01-1), which causes another cosmological disaster. Consequently, the cosmological moduli problem cannot be solved simply by making the modulus mass heavier than 100 TeV. We also illustrate our results by explicitly calculating the branching ratio into the gravitinos in the mixed modulus--anomaly/KKLT- and racetrack-type models.

Figures (1)

• Figure 1: The cosmological bounds on $m_{3/2}$ and $B_{3/2}$. Shaded regions are excluded by cosmological arguments. See the text for details. The horizontal dashed line denotes the BBN bound from the stau NLSP decay into gravitinos for $m_{\rm NLSP}=100$ GeV. We have chosen $m_X = 10^3$ TeV and $c=1$ as representative values. The bounds become severer for larger $m_X$.