arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0904.1735hep-ph
收藏

质子的自旋和轨道angular momentum

Spin and orbital angular momentum of the proton

A. W. Thomas

摘要:

自从欧洲μ子合作组织宣布质子自旋危机以来,在解开质子内自旋和轨道角动量的分布方面取得了相当大的进展。我们回顾了目前的状况的问题,表明不仅有强大的上限已被放置在质子的极化胶的量,但自旋内容的实验测定已变得更加精确。现在很清楚,实验和对质子中夸克和反夸克携带的自旋分数的天真期望之间的差异的根源在于质子的非微扰结构。我们解释如何在一个现代的,相对论性和手征对称的描述核子结构的功能,自然解释目前的数据。本文评述了这一解释对夸克和胶子轨道角动量存在的影响,并与最近的格点量子色动力学和实验结果作了比较。

英文摘要:

Since the announcement of the proton spin crisis by the European Muon Collaboration there has been considerable progress in unravelling the distribution of spin and orbital angular momentum within the proton. We review the current status of the problem, showing that not only have strong upper limits have been placed on the amount of polarized glue in the proton but that the experimental determination of the spin content has become much more precise. It is now clear that the origin of the discrepancy between experiment and the naive expectation of the fraction of spin carried by the quarks and anti-quarks in the proton lies in the non-perturbative structure of the proton. We explain how the features expected in a modern, relativistic and chirally symmetric description of nucleon structure naturally explain the current data. The consequences of this explanation for the presence of orbital angular momentum on quarks and gluons is reviewed and comparison made with recent results from lattice QCD and experimental data.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑