核子中部分子携带的自旋和动量分数
Spin and momentum fraction carried by partons in the nucleon
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中文总结 AI 辅助
该研究在格点量子色动力学中，通过特定系综确定质子中夸克和胶子的动量分数与角动量，在连续极限下提取相关量，得出总动量分数和总自旋，验证了动量和自旋求和规则，并与唯象分析结果对比。
中文摘要 AI 辅助
我们在格点量子色动力学中确定质子中夸克和胶子携带的动量分数和角动量。我们使用了四个包含上、下、奇和粲夸克的系综，其质量调至物理值。这些系综有相似物理体积和不同格距，能在物理π介子质量点直接取连续极限。我们在连续极限下提取夸克和胶子动量分数、总角动量以及质子自旋中固有夸克自旋和轨道角动量贡献。结果表明总动量分数⟨x_N⟩ = 0.995(60)(29)，总自旋J_N = 0.507(43)(65)，满足动量和自旋求和规则，并与唯象分析结果作了比较。
英文摘要
We determine the momentum fraction and angular momentum carried by quarks and gluons in the proton in lattice QCD. We use four ensembles simulated with up, down, strange and charm quarks with their masses tuned to their physical values. These ensembles have similar physical volume and different lattice spacings allowing us to take the continuum limit directly at the physical pion mass point. We extract the quark and gluon momentum fractions and total angular momentum in the continuum limit as well as the intrinsic quark spin and orbital angular momentum contributions to the proton spin. We find the total momentum fraction $\langle x_N \rangle= 0.995(60)(29)$ and the total spin $J_N = 0.507(43)(65)$, showing that both the momentum and spin sum rules are satisfied. We compare our results to those extracted from phenomenological analyses.
