Non-perturbative decay of udd and QLd flat directions

TL;DR

This paper investigates the non-perturbative decay mechanisms of certain flat directions in the MSSM, showing that they can decay rapidly through non-adiabatic effects, impacting early universe thermalization.

Contribution

It demonstrates that udd and QLd flat directions can undergo fast non-perturbative decay, extending previous toy model analyses to realistic MSSM flat directions.

Findings

Flat directions can decay non-perturbatively during inflation.

Decay occurs via non-adiabatic evolution of eigenstates.

Decay dynamics can be modeled by gauged toy models.

Abstract

The Minimal Supersymmetric Standard Model has several flat directions, which can naturally be excited during inflation. If they have a slow (perturbative) decay, they may affect the thermalization of the inflaton decay products. In the present paper, we consider the system of udd and QLd flat directions, which breaks the U(1)xSU(2)xSU(3) symmetry completely. In the unitary gauge and assuming a general soft breaking mass configuration, we show that for a range of parameters, the background condensate of flat directions can undergo a fast non-perturbative decay, due to non-adiabatic evolution of the eigenstates. We find that both the background evolution and part of the decay can be described accurately by previously studied gauged toy models of flat direction decay.