Nucleon charges, form-factors and neutron EDM

Abstract

We present an update of our analysis of statistical and systematic errors in the calculation of iso-vector scalar, axial and tensor charges of the nucleon. The calculations are done using Nf = 2+1+1 flavor HISQ ensembles generated by the MILC Collaboration at three values of the lattice spacing (a = 0:12; 0:09; and 0:06 fm) and three values of the quark mass (Mπ ≈ 310; 220 and 130 MeV); and clover fermions for calculating the correlation functions, i.e., we use a cloveron- HISQ lattice formulation. The all-mode-Averaging method allows us to increase the statistics by a factor of eight for the same computational cost leading to a better understanding of and control over excited state contamination. Our current results, after extrapolation to the continuum limit and physical pION mass are gu-d A = 1:21(3), gu-dT = 1:005(59) and gu-d S = 0:95(12). Further checks of control over all systematic errors, especially in gu-d A , are still being performed. Using results for the flavor-diagonal charges, guT , gdT and gsT , we analyze contributions of the quark electric dipole moment to the neutron EDM and the consequences for split SUSY model.