Mixed Axion/Axino Dark Matter in mSUGRA and Yukawa-unified SUSY

TL;DR

This paper investigates mixed axion/axino dark matter within mSUGRA and Yukawa-unified SUSY GUT models, highlighting the components, conditions for high reheat temperatures, and implications for baryogenesis and BBN.

Contribution

It presents a detailed analysis of axion/axino dark matter scenarios in specific SUSY models, emphasizing the required parameters for high reheat temperatures and baryogenesis.

Findings

Relic dark matter has three components: cold axions, warm axinos from neutralino decay, and thermally produced axinos.

Reheat temperatures above 10^6 GeV are necessary for solving gravitino/BBN problems and enabling non-thermal leptogenesis.

High Peccei-Quinn scale ($10^{11}$-$10^{12}$ GeV) is essential for achieving these conditions.

Abstract

Axion/axino dark matter (DM) is explored in the minimal supergravity (mSUGRA) and Yukawa-unified supersymmetric grand-unified theory (SUSY GUT) models with surprising results. For this type of scenario, relic DM abundance has three components: {\it i}.) cold axions, {\it ii.}) warm axinos from neutralino decay, and {\it iii.}) cold or warm thermally produced axinos. Reheat temperatures $T_R$ exceeding $10^6$ GeV are required in order to solve the gravitino/Big Bang Nucleosynthesis (BBN) problem while also allowing for baryogensis via non-thermal leptogenesis. In order to attain high enough reheat temperatures, we also need high values of the Peccei-Quinn (PQ) breaking scale $f_a$ on the order $10^{11}$-$10^{12}$ GeV.