CP Violating Bubble Wall Profiles

TL;DR

This paper investigates CP violation in the MSSM bubble walls during the electroweak phase transition, finding limited spontaneous CP violation and discussing implications for baryogenesis.

Contribution

It provides a detailed analysis of CP violating phases in the MSSM bubble wall, challenging previous ideas of spontaneous CP violation and exploring effects of explicit CP violation.

Findings

No evidence of spontaneous CP violation in MSSM bubble walls

Explicit CP violation causes only mild space dependence of phases

Potential for spontaneous CP violation if MSSM is extended with a singlet

Abstract

We solve the equations of motion for a CP violating phase between the two Higgs doublets at the bubble wall of the MSSM electroweak phase transition. Contrary to earlier suggestions, we do not find indications of spontaneous ``transitional'' CP violation in the MSSM. On the other hand, in case there is explicit CP violation in the stop and chargino/neutralino sectors, the relative phase between the Higgses does become space dependent, but only mildly even in the maximal case. We also demonstrate that spontaneous CP violation within the bubble wall could occur, e.g., if the Higgs sector of the MSSM were supplemented by a singlet. Finally we point out some implications for baryogenesis computations.