论文标题
质子GPD的夸克自旋和轨道角动量
Quark spin and orbital angular momentum from proton GPDs
论文作者
论文摘要
我们计算质量染色体动力学（QCD）的Nambu-Jona-Lasinio（NJL）模型中有限偏度的质子的主要旋转螺旋依赖性的普遍分布（GPD）。从这些（且先前计算的无螺旋性与GPD）中，我们获得了质子的自旋分解，包括预测夸克内在的自旋和轨道角动量。发现包含多种diquarks对风味分解具有显着影响，并且解决这些动态diquark相关性的内部结构被证明对质子的机械稳定性至关重要。 At a scale of $Q^2=4\,$GeV$^2$ we find that the up and down quarks carry an intrinsic spin and orbital angular momentum of $S_u=0.534$, $S_d=-0.214$, $L_u=-0.189$, and $L_d=0.210$, whereas the gluons have a total angular momentum of $ J_G = 0.151 $。因此，由于自旋和轨道贡献之间的取消，下夸克几乎没有总角动量。这些自旋分解结果与晶格QCD计算之间进行了比较。
We calculate the leading-twist helicity-dependent generalized parton distributions (GPDs) of the proton at finite skewness in the Nambu--Jona-Lasinio (NJL) model of quantum chromodynamics (QCD). From these (and previously calculated helicity-independent GPDs) we obtain the spin decomposition of the proton, including predictions for quark intrinsic spin and orbital angular momentum. The inclusion of multiple species of diquarks is found to have a significant effect on the flavor decomposition, and resolving the internal structure of these dynamical diquark correlations proves essential for the mechanical stability of the proton. At a scale of $Q^2=4\,$GeV$^2$ we find that the up and down quarks carry an intrinsic spin and orbital angular momentum of $S_u=0.534$, $S_d=-0.214$, $L_u=-0.189$, and $L_d=0.210$, whereas the gluons have a total angular momentum of $J_g=0.151$. The down quark is therefore found to carry almost no total angular momentum due to cancellations between spin and orbital contributions. Comparisons are made between these spin decomposition results and lattice QCD calculations.
