Examining leptogenesis with lepton flavor violation and the dark matter abundance

TL;DR

This paper investigates leptogenesis within a supersymmetric seesaw model, exploring how it can explain the Universe's baryon asymmetry while considering dark matter constraints and lepton flavor violation signals.

Contribution

It analyzes thermal and non-thermal leptogenesis scenarios in SUSY models, highlighting conditions that reconcile baryon asymmetry, dark matter, and lepton flavor violation.

Findings

Thermal leptogenesis is highly constrained by reheat temperature and gravitino problem.

Non-thermal leptogenesis relaxes these constraints, allowing for consistent baryon asymmetry and dark matter.

LFV processes could be observed in current or future experiments in certain parameter regions.

Abstract

Within a supersymmetric (SUSY) type-I seesaw framework with flavor-blind universal boundary conditions, we study the consequences of requiring that the observed baryon asymmetry of the Universe be explained by either thermal or non-thermal leptogenesis. In the former case, we find that the parameter space is very constrained. In the bulk and stop-coannihilation regions of mSUGRA parameter space (that are consistent with the measured dark matter abundance), lepton flavor-violating (LFV) processes are accessible at MEG and future experiments. However, the very high reheat temperature of the Universe needed after inflation (of about 10^{12} GeV) leads to a severe gravitino problem, which disfavors either thermal leptogenesis or neutralino dark matter. Non-thermal leptogenesis in the preheating phase from SUSY flat directions relaxes the gravitino problem by lowering the required reheat temperature. The baryon asymmetry can then be explained while preserving neutralino dark matter, and for the bulk or stop-coannihilation regions LFV processes should be observed in current or future experiments.