Why the early Universe preferred the non-supersymmetric vacuum: Part II

TL;DR

This paper investigates the early Universe's preference for the non-supersymmetric vacuum in ISS models, showing that thermal effects and gauge dynamics favor the metastable SUSY-breaking vacuum under realistic conditions.

Contribution

It extends previous work by analyzing the impact of gauge sector mass gaps and MSSM back reaction, demonstrating these factors reinforce the Universe's tendency to settle in the SUSY-breaking vacuum.

Findings

Mass-gap effects lower the temperature threshold for vacuum transition.

Thermal effects strongly favor the metastable SUSY-breaking vacuum.

MSSM sector coupling has negligible impact on vacuum stability.

Abstract

It was recently shown in hep-th/0610334 that in the context of the ISS models with a metastable supersymmetry breaking vacuum, thermal effects generically drive the Universe to the metastable vacuum even if it began after inflation in the supersymmetry-preserving one. We continue this programme and specifically take into account two new effects. First is the effect of the mass-gap of the gauge degrees of freedom in the confining supersymmetry preserving vacua, and second, is the effect of the back reaction of the MSSM sector on the SUSY breaking ISS sector. It is shown that, even though the mass-gap is parametrically smaller than the <\phi> vevs, it drastically reduces the temperature required for the Universe to be driven to the metastable vacuum: essentially any temperature larger than the supersymmetry breaking scale \mu is sufficient. On the other hand we also find that any reasonable transmission of SUSY breaking to the MSSM sector has no effect on the vacuum transitions to, and the stability of the SUSY breaking vacuum. We conclude that for these models the early Universe does end up in the SUSY breaking vacuum.