Nuclear Electric Dipole Moments in Chiral Effective Field Theory

TL;DR

This paper presents a comprehensive calculation of electric dipole moments for light nuclei within chiral effective field theory, including novel contributions from the three-pion operator, to better understand CP violation.

Contribution

It provides the first calculation of EDM contributions from the CP-violating three-pion operator and compares contact interaction effects with phenomenological models.

Findings

CP-violating nucleon-nucleon contact interactions are more significant than previously thought.

Results are applicable to various CP violation models, including the QCD θ-term and left-right symmetric models.

The study advances the theoretical understanding of nuclear EDMs in chiral EFT.

Abstract

We provide a consistent and complete calculation of the electric dipole moments of the deuteron, helion, and triton in the framework of chiral effective field theory. The CP-conserving and CP-violating interactions are treated on equal footing and we consider CP-violating one-, two-, and three-nucleon operators up to next-to-leading-order in the chiral power counting. In particular, we calculate for the first time EDM contributions induced by the CP-violating three-pion operator. We find that effects of CP-violating nucleon-nucleon contact interactions are larger than those found in previous studies based on phenomenological models for the CP-conserving nucleon-nucleon interactions. Our results which apply to any model of CP violation in the hadronic sector can be used to test various scenarios of CP violation. As examples, we study the implications of our results on the QCD $\theta$-term and the minimal left-right symmetric model.