Unpolarized and Helicity Generalized Parton Distributions of the Proton within Lattice QCD
Abstract
We present the first calculation of the x dependence of the proton generalized parton distributions (GPDs) within lattice QCD. Results are obtained for the isovector unpolarized and helicity GPDs. We compute the appropriate matrix elements of fastmoving protons coupled to nonlocal operators containing a Wilson line. We present results for proton momenta 0.83,1.25,1.67 GeV, and momentum transfer squared 0.69,1.38 GeV^{2} . These combinations include cases with zero and nonzero skewness. The calculation is performed using one ensemble of two degenerate mass light quarks, a strange quark, and a charm quark of maximally twisted mass fermions with a clover term. The lattice results are matched to the lightcone GPDs using oneloop perturbation theory within the framework of large momentum effective theory. The final GPDs are given in the MS ¯ scheme at a scale of 2 GeV.
 Publication:

Physical Review Letters
 Pub Date:
 December 2020
 DOI:
 10.1103/PhysRevLett.125.262001
 arXiv:
 arXiv:2008.10573
 Bibcode:
 2020PhRvL.125z2001A
 Keywords:

 High Energy Physics  Lattice;
 High Energy Physics  Experiment;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 Main document: 5 pages, Supplementary document (Appendix): 10 pages. Version accepted for publication in Physical Review Letters