# Baryogenesis, Dark Matter, and Flavor Structure in Non-thermal Moduli Cosmology

## TL;DR

This paper proposes a string-inspired non-thermal moduli cosmology framework that addresses key issues in particle physics and cosmology, including baryogenesis, dark matter, and flavor structure, while avoiding common supersymmetric model problems.

## Contribution

It introduces a novel model based on discrete symmetries and anomaly cancellation that simultaneously explains fermion masses, neutrino smallness, baryogenesis, and dark matter abundance.

## Key findings

- Moduli decay explains baryon and dark matter densities.
- Model avoids the μ-problem and rapid proton decay issues.
- Compatible with SU(5) Grand Unification.

## Abstract

The appearance of scalar/moduli fields in the early universe, as motivated by string theory, naturally leads to non-thermal "moduli cosmology". Such cosmology provides a consistent framework where the generation of radiation, baryons, and dark matter can occur while maintaining successful Big Bang Nucleosynthesis and avoiding the cosmological moduli problem. We present a relatively economical construction with moduli cosmology, building on a variety of string-inspired components (e.g. supersymmetry, discrete symmetries, Green-Schwarz anomaly cancellation). We address a range of outstanding problems of particle physics and cosmology simultaneously, including the fermion mass hierarchy and flavor puzzle, the smallness of neutrino masses, baryogenesis and dark matter. Our setup, based on discrete $\mathrm{Z}_{12}^{R}$ symmetry and anomalous $\mathrm{U}(1)_A$, is void of the usual issues plaguing the Minimal Supersymmetric Standard Model, i.e. the $\mu$-problem and the overly-rapid proton decay due to dimension-4,-5 operators. The model is compatible with $\mathrm{SU}(5)$ Grand Unification. The smallness of Dirac neutrino masses is automatically established by requiring the cancellation of mixed gravitational-gauge anomalies. The decay of the moduli field provides a common origin for the baryon number and dark matter abundance, explaining the observed cosmic coincidences, $\Omega_{B} \sim \Omega_{DM}$.