Pion Valence Quark Distribution at Large $x$ from Lattice QCD

Raza Sabbir Sufian, Colin Egerer, Joseph Karpie, Robert G. Edwards, Bálint Joó, Yan-Qing Ma, 5, 6 Kostas Orginos, 2 Jian-Wei Qiu, and David G. Richards Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA Physics Department, William and Mary, Williamsburg, Virginia 23187, USA Physics Department, Columbia University, New York City, New York 10027, USA School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China Center for High Energy physics, Peking University, Beijing100871, China Collaborative Innovation Center of Quantum Matter, Beijing 100871, China Using a short-distance collinear factorization, the pion valence quark distribution q v (x) is extracted from spacelike correlations of antisymmetrized vector and axial-vector (V-A) currents, where the employed perturbative hard coefficient is derived to one-loop. Finite lattice spacing, volume, and quark mass dependencies are investigated in a simultaneous fit of matrix elements computed on four gauge ensembles, providing a physical limit Ioffe time distribution. Using two different phenomenologically motivated parametrizations of q v (x), the q π v (x) distribution is found to be in very good agreement with that extracted from experimental data. At large x, a softer valence quark distribution is slightly favored by the figure of merit of this calculation. These two distributions are consistent within uncertainty and reproduce the extraction of q v (x) from the experimental data in the entire x-region, showing the robustness of our calculation.