格点量子色动力学对次下领头阶部分子分布函数的 Bjorken-x 依赖性的确定。

Lattice QCD Determination of the Bjorken-x Dependence of Parton Distribution Functions at Next-to-Next-to-Leading Order.

作者信息

Gao Xiang, Hanlon Andrew D, Mukherjee Swagato, Petreczky Peter, Scior Philipp, Syritsyn Sergey, Zhao Yong

机构信息

Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China.

Physics Department, Brookhaven National Laboratory, Building 510A, Upton, New York 11973, USA.

出版信息

Phys Rev Lett. 2022 Apr 8;128(14):142003. doi: 10.1103/PhysRevLett.128.142003.

DOI:10.1103/PhysRevLett.128.142003

PMID:35476471

Abstract

We report the first lattice QCD calculation of pion valence quark distribution with next-to-next-to-leading order perturbative matching correction, which is done using two fine lattices with spacings a=0.04 and 0.06 fm and valence pion mass m_{π}=300 MeV, at boost momentum as large as 2.42 GeV. As a crucial step to control the systematics, we renormalize the pion valence quasidistribution in the recently proposed hybrid scheme, which features a Wilson-line mass subtraction at large distances in coordinate space, and develop a procedure to match it to the MS[over ¯] scheme. We demonstrate that the renormalization and the perturbative matching in Bjorken-x space yield a reliable determination of the valence quark distribution for 0.03≲x≲0.80 with 5%-20% uncertainties.

摘要

我们报告了对π介子价夸克分布进行的首次格点量子色动力学计算，其中包含次领头阶微扰匹配修正，该计算使用了两个精细格点，间距分别为a = 0.04和0.06飞米，价π介子质量mπ = 300兆电子伏特，在高达2.42吉电子伏特的推进动量下进行。作为控制系统误差的关键步骤，我们在最近提出的混合方案中对π介子价准分布进行重整化，该方案在坐标空间的大距离处具有威尔逊线质量减法，并开发了一种将其与MS[上划线]方案匹配的程序。我们证明，在比约肯x空间中的重整化和微扰匹配能够可靠地确定0.03≲x≲0.80范围内价夸克分布，不确定性为5%-20%。