Neutron electric dipole moment from isovector quark chromo-electric dipole moment

TL;DR

This study uses lattice QCD to evaluate how the isovector quark chromo-electric dipole moment contributes to the neutron electric dipole moment, providing a first-principles calculation with controlled divergences.

Contribution

It presents a lattice QCD calculation of the neutron EDM from the isovector quark cEDM operator, addressing operator mixing and scheme conversion.

Findings

Neutron EDM contribution from isovector qcEDM calculated.

Controlled power-divergent mixing with pseudoscalar operator.

Results converted to MS scheme at leading-log order.

Abstract

We present results from our lattice QCD study of the contribution of the isovector quark cEDM (qcEDM) operator to the neutron EDM. The calculation was carried out on four 2+1+1-flavor highly improved staggered quark ensembles (provided to us by the MILC collaboration) using Wilson-clover quarks to construct correlation functions. We use the nonsinglet axial Ward identity including corrections up to O(a) to show how to control the power-divergent mixing of the isovector qcEDM operator with the lower dimensional pseudoscalar operator. Results for the nEDM are presented after conversion to the MS scheme at the leading-log order.