Neutron and proton electric dipole moments from $N_f=2+1$ domain-wall fermion lattice QCD

TL;DR

This paper reports a lattice QCD calculation of neutron and proton electric dipole moments using $N_f=2+1$ domain-wall fermions, providing insights into their chiral behavior and topological correlations.

Contribution

First lattice QCD calculation of nucleon EDMs with $N_f=2+1$ domain-wall fermions, analyzing chiral behavior and topological effects.

Findings

Neutron and proton EDM form factors extracted at next-to-leading order

Chiral behavior of EDMs discussed in baryon chiral perturbation theory context

Numerical evidence links correlation functions with topological distribution

Abstract

We present a lattice calculation of the neutron and proton electric dipole moments (EDM's) with $N_f=2+1$ flavors of domain-wall fermions. The neutron and proton EDM form factors are extracted from three-point functions at the next-to-leading order in the $\theta$ vacuum of QCD. In this computation, we use pion masses 0.33 and 0.42 GeV and 2.7 fm$^3$ lattices with Iwasaki gauge action and a 0.17 GeV pion and 4.6 fm$^3$ lattice with I-DSDR gauge action, all generated by the RBC and UKQCD collaborations. The all-mode-averaging technique enables an efficient and high statistics calculation. Chiral behavior of lattice EDM's is discussed in the context of baryon chiral perturbation theory. In addition, we also show numerical evidence on relationship of three- and two-point correlation function with local topological distribution.