Neutron electric dipole moments with clover fermions

Abstract

We present preliminary results for the contributions to the neutron EDM arising from the QCD θ-term, the Weinberg three-gluon and the quark chromo-EDM operators from our ongoing lattice calculations using clover valence quarks on the MILC HISQ lattices. We use the gradient-flow technique to smooth the lattices and renormalize the gluonic operators, and use the Schwinger source method to incorporate the quark chromo-EDM interactions in the quark propagator. For the QCD θ-term and the Weinberg three-gluon operator, we report results in the gradient-flow scheme from 8 ensembles at four lattice spacings and three pion masses, including 2 physical pion mass ensembles described in Table 1. For the quark chromo-EDM, unrenormalized results are presented at two lattice spacings, a = 0.12 and 0.09 fm, and two pion masses, Mπ = 310 MeV and 220 MeV.