English

Nucleon Charges, Form-factors and Neutron EDM

High Energy Physics - Lattice 2016-01-11 v1 Nuclear Theory

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+1N_f=2+1+1 flavor HISQ ensembles generated by the MILC Collaboration at three values of the lattice spacing (a=0.12, 0.09,a=0.12,\ 0.09, and 0.060.06 fm) and three values of the quark mass (Mπ310, 220M_\pi \approx 310,\ 220 and 130130 MeV); and clover fermions for calculating the correlation functions, i.e., we use a clover-on-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 gAud=1.21(3)g_A^{u-d} = 1.21(3), gTud=1.005(59)g_T^{u-d} = 1.005(59) and gSud=0.95(12)g_S^{u-d} = 0.95(12) . Further checks of control over all systematic errors, especially in gAudg_A^{u-d}, are still being performed. Using results for the flavor-diagonal charges, gTug_T^{u} , gTdg_T^{d} and gTsg_T^{s}, we analyze contributions of the quark electric dipole moment to the neutron EDM and the consequences for split SUSY model.

Keywords

Cite

@article{arxiv.1601.01730,
  title  = {Nucleon Charges, Form-factors and Neutron EDM},
  author = {Rajan Gupta and Tanmoy Bhattacharya and Vincenzo Cirigliano and Huey-Wen Lin and Boram Yoon},
  journal= {arXiv preprint arXiv:1601.01730},
  year   = {2016}
}

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Talk at Lattice 2015