A simple model for particle physics and cosmology

TL;DR

This paper introduces a simple extension to the minimal supersymmetric standard model that addresses key issues in particle physics and cosmology, including neutrino masses, dark matter, and baryogenesis, through thermal inflation and axion-related mechanisms.

Contribution

It presents a minimal supersymmetric model extension incorporating a gauge singlet and right-handed neutrinos, unifying solutions to multiple cosmological and particle physics problems.

Findings

Model naturally explains neutrino masses and the MSSM μ-parameter.

Predicts axino dark matter with a mass around 1 GeV.

Constrains axion coupling and decay temperature for consistent cosmology.

Abstract

We propose a simple extension of the minimal supersymmetric standard model by introducing a gauge singlet in addition to right-handed neutrinos. The model resolves the strong CP problem by Pecci-Quinn symmetry, explains the origin of left-handed neutrino masses as well as MSSM $\mu$-parameter. It also gives rise to thermal inflation, baryogenesis and dark matter in a remarkably consistent way. Interestingly, resolution of moduli problem by thermal inflation constrains tightly axion coupling constant and flaton decay temperature to be $f_a \sim 10^{12} \GeV$ and $T_\mathrm{d} \sim 100 \MeV$, respectively. Model parameters in this case are likely to give right amount of baryon asymmetry and dark matter at present. The main component of dark matter is expected to be the axino whose mass is nearly fixed to be about $1 \GeV$.