Higgs, Moduli Problem, Baryogenesis and Large Volume Compactifications

TL;DR

This work addresses cosmology in high-scale SUSY linked to a 125 GeV Higgs by stabilizing moduli within the LARGE Volume Scenario (LVS) to suppress gravitino production from modulus decays. It demonstrates that the Affleck-Dine mechanism, potentially aided by an enhanced inflaton–AD coupling, can generate the observed baryon asymmetry despite large entropy production from modulus domination, with Q-balls decaying safely before BBN. The analysis covers both geometric and singular LVS regimes, showing that in the geometric case the lightest modulus decays early and can dilute unwanted relics, while in the singular case decay patterns, cutoff scales, and dark radiation signatures differ but can still accommodate the observed matter content. Together, these results imply that high-scale SUSY with LVS offers a viable path to simultaneously solving the moduli/gravitino problems and producing the baryon asymmetry, with distinctive observational implications from axionic dark radiation.

Abstract

We consider the cosmological moduli problem in the context of high-scale supersymmetry breaking suggested by the recent discovery of the standard-model like Higgs boson. In order to solve the notorious moduli-induced gravitino problem, we focus on the LARGE volume scenario, in which the modulus decay into gravitinos can be kinematically forbidden. We then consider the Affleck-Dine mechanism with or without an enhanced coupling with the inflaton, taking account of possible Q-ball formation. We show that the baryon asymmetry of the present Universe can be generated by the Affleck-Dine mechanism in LARGE volume scenario, solving the moduli and gravitino problems. We also find that the overall volume modulus decays into a pair of the axionic superpartners, which contribute to the extra relativistic degrees of freedom.