论文标题
晶格QCD的质子结构的新见解：twist-3 parton发行函数$ g_t（x）$
New insights on proton structure from lattice QCD: the twist-3 parton distribution function $g_T(x)$
论文作者
论文摘要
在这项工作中，我们介绍了从Lattice QCD的质子质量的twist-3 Parton分布函数的等值器风味组合的第一个计算。我们使用两种简并光的仪表配置合奏，一个奇怪的和一个魅力夸克（$ n_f = 2+1+1+1 $）的最大扭曲的质量费米子，并改善了三叶草。晶格的空间范围为3 〜fm，晶格间距为0.093〜fm，并且重现了$ 260 $ MEV的茶质量。我们使用准分布方法，并采用质子动量增强的三个值，0.83 GEV，1.25 GEV和1.67 GEV。我们使用1.12〜FM的源 - 链接分离来抑制激发态的污染。晶格数据非扰动地重新归一化。我们计算大动量有效理论中的匹配方程，该理论应用于晶格数据以获得$ g_t $。最终分布以$ \ Overline {\ rm MS} $方案的比例为2 GEV。我们还计算了螺旋分布$ g_1 $，以测试$ g_t $的wandzura-wilczek近似。我们发现近似值在$ x $的广泛范围内很好地效果很好。这项工作证明了从晶格QCD中的新方法访问Twist-3 Parton分布函数的可行性，并可以为Hadron的结构提供基本的见解。
In this work, we present the first-ever calculation of the isovector flavor combination of the twist-3 parton distribution function $g_T(x)$ for the proton from lattice QCD. We use an ensemble of gauge configurations with two degenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with a clover improvement. The lattice has a spatial extent of 3~fm, lattice spacing of 0.093~fm, and reproduces a pion mass of $260$ MeV. We use the quasi-distribution approach and employ three values of the proton momentum boost, 0.83 GeV, 1.25 GeV, and 1.67 GeV. We use a source-sink separation of 1.12~fm to suppress excited-states contamination. The lattice data are renormalized non-perturbatively. We calculate the matching equation within Large Momentum Effective Theory, which is applied to the lattice data in order to obtain $g_T$. The final distribution is presented in the $\overline{\rm MS}$ scheme at a scale of 2 GeV. We also calculate the helicity distribution $g_1$ to test the Wandzura-Wilczek approximation for $g_T$. We find that the approximation works well for a broad range of $x$. This work demonstrates the feasibility of accessing twist-3 parton distribution functions from novel methods within lattice QCD and can provide essential insights into the structure of hadrons.
