We present a detailed analysis of statistical and systematic errors in the calculation of matrix elements of iso-vector scalar, axial and tensor charges between a neutron and a proton state. These analyses are being done on dynamical Nf=2+1+1 HISQ configurations generated by the MILC Collaboration using valence clover fermions. Using ensembles 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) we find that the estimates of the tensor charge are stable and it can be extracted with 5% precision with O(10,000) measurements. We also find that higher statistics are needed to resolve the various uncertainties in the calculation of gA and improve the signal in gS, which with present data has large errors. A brief status report on the mixing and renormalization of novel operators contributing to nEDM is also given.
@article{arxiv.1501.07639,
title = {Precision calculations of nucleon charges $g_A$, $g_S$, $g_T$},
author = {Rajan Gupta and Tanmoy Bhattacharya and Anosh Joseph and Huey-Wen Lin and Boram Yoon},
journal= {arXiv preprint arXiv:1501.07639},
year = {2015}
}