Nucleon charges and electromagnetic form factors from 2+1+1-flavor lattice QCD

作者：Bhattacharya Tanmoy^*; Cohen Saul D; Gupta Rajan; Joseph Anosh; Lin Huey Wen; Yoon Boram

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2014, 89(9): 094502.

DOI：10.1103/PhysRevD.89.094502

We present lattice-QCD results on the nucleon isovector axial, scalar and tensor charges, the isovector electromagnetic Dirac and Pauli form factors, and the connected parts of the isoscalar charges. The calculations have been done using two ensembles of highly improved staggered quarks lattices generated by the MILC collaboration with 2 + 1 + 1 dynamical flavors at a lattice spacing of 0.12 fm and with light-quark masses corresponding to pions with masses 310 and 220 MeV. We perform a systematic study including excited-state degrees of freedom and examine the dependence of the extracted nucleon matrix elements on source-sink separation. This study demonstrates with high-statistics data that including excited-state contributions and generating data at multiple separations is necessary to remove contamination that would otherwise lead to systematic error. We also determine the renormalization constants of the associated quark bilinear operators in the RI-sMOM scheme and make comparisons of our renormalized results with previous dynamical-lattice calculations.

• 出版日期2014-5-6
• 单位Los Alamos