We present the first attempt to access the x dependence of the gluon unpolarized parton-distribution function (PDF), based on lattice simulations using the large-momentum effective theory approach. The lattice calculation is carried out with pion masses of 340 and 678 MeV on a (2+1)-flavor domain-wall fermion configuration with lattice spacing a = 0.111 fm, for the gluon quasi-PDF matrix element with the nucleon momentum up to 0.93 GeV. Taking the normalization from similar matrix elements in the rest frame of the nucleon and pion, our results for these matrix elements are consistent with the Fourier transform of the global fit CT14 and PDF4LHC15 NNLO of the gluon PDF, within statistical uncertainty and the systematic one up to power corrections, perturbative O(αs) matching and the mixing from the quark PDFs.
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Funded by SCOAP3.
Z. F., H. L., and Y. Y. are supported by the U.S. National Science Foundation under Grant No. PHY 1653405 “CAREER: Constraining Parton Distribution Functions for New-Physics Searches.” K. L. is partially supported by DOE Grant No. DE-SC0013065 and DOE TMD topical collaboration. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 through ALCC and ERCAP; facilities of the USQCD Collaboration, which are funded by the Office of Science of the U.S. Department of Energy, and supported in part by Michigan State University through computational resources provided by the Institute for Cyber-Enabled Research.
Fan, Zhou-You; Yang, Yi-Bo; Anthony, Adam; Lin, Huey-Wen; and Liu, Keh-Fei, "Gluon Quasi-Parton-Distribution Functions from Lattice QCD" (2018). Physics and Astronomy Faculty Publications. 620.