标题： 坐标空间中的核子夸克和胶子分布 显示英文标题

标题： Nuclear Quark and Gluon Distributions in Coordinate Space

摘要： 在坐标空间中，核子的夸克和胶子分布定义为涉及两个由光锥距离$y^+ = 2l$分离的场算符的相关函数。 我们研究这些分布的核修改。 最大的效应是在大纵向距离处部分子分布（阴影效应）的强烈耗尽，所有部分子种类在$l=2$法米时开始发生，即在核中的平均核子-核子分离处。 另一方面，核半径并不起重要作用。 在$l \lsim 1$法米时，部分子分布的核修改很小。 单个核子的内在结构显然并未受到核结合的很大影响。 特别是，没有证据表明束缚核子中的夸克或胶子关联长度有显著增加。 显示英文摘要

摘要： In coordinate space, quark and gluon distributions of the nucleon are defined as correlation functions involving two field operators separated by a light-cone distance $y^+ = 2l$. We study the nuclear modifications of these distributions. The largest effect is a strong depletion of parton distributions (shadowing) at large longitudinal distances, which starts for all parton species at $l=2$ fm, i.e. at the average nucleon-nucleon separation in nuclei. On the other hand, the nuclear radius does not play a significant role. At $l \lsim 1$ fm, nuclear modifications of parton distributions are small. The intrinsic structure of individual nucleons is evidently not very much affected by nuclear binding. In particular, there is no evidence for a significant increase of the quark or gluon correlation length in bound nucleons.