Revisiting the Electron EDM in the NMSSM

TL;DR

This paper investigates two-loop contributions to electron EDMs in the NMSSM with CP violation, revealing cancellations and constraints that impact baryogenesis models.

Contribution

It identifies previously overlooked two-loop diagrams affecting fermion EDMs in the NMSSM, refining the understanding of CP-violating phase constraints.

Findings

Certain CP phases lead to partial cancellations of EDM contributions.

Some diagrams dominate and tighten EDM bounds, requiring fine-tuning.

Results impact the viability of baryogenesis scenarios in the NMSSM.

Abstract

The Next-to-Minimal Supersymmetric Standard Model (NMSSM) with explicit CP violation offers a promising framework for explaining the observed baryon asymmetry while remaining consistent with stringent electric dipole moment (EDM) bounds. In this work, we identify a previously overlooked set of two-loop diagrams that contribute to fermion EDMs in the NMSSM. Our analysis of the electron EDM shows that, for certain NMSSM specific CP-violating phases, these diagrams partially cancel existing contributions, thereby relaxing the associated constraints. In other phases, the diagrams dominate and tighten the bounds, which in turn necessitates more finely tuned parameters to reconcile successful baryogenesis with current EDM limits.