We employ dimension-4 operators to improve the local vector and axial-vector currents and calculate the nucleon isovector axial coupling g3A with overlap valence on 2 + 1-flavor domain wall fermion (DWF) sea. Using the equality of g3A from the spatial and temporal components of the axial-vector current as a normalization condition, we find that g3A is increased by a few percent towards the experimental value. The excited-state contamination has been taken into account with three time separations between the source and sink. The improved axial charges g3A(24I) = 1.22(4)(3) and g3A(32I) = 1.21(3)(3) are obtained on a 243 × 64 lattice at pion mass of 330 MeV and a 323 × 64 lattice at pion mass 300 MeV and are increased by 3.4% and 1.7% from their unimproved values, respectively. We have also used clover fermions on the same DWF configurations and find the same behavior for the local axial charge as that with overlap fermions.
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This work is supported in part by the U.S. DOE Grant No. DE-SC0013065. This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. This work also used Stampede time under the Extreme Science and Engineering Discovery Environment (XSEDE) , which is supported by National Science Foundation Grant No. ACI-1053575.
Liang, Jian; Yang, Yi-Bo; Liu, Keh-Fei; Alexandru, Andrei; Draper, Terrence; and Sufian, Raza Sabbir, "Lattice Calculation of Nucleon Isovector Axial Charge with Improved Currents" (2017). Physics and Astronomy Faculty Publications. 541.