标题： 夸克模型对部分子分布中对称性破缺的计算 显示英文标题

标题： Quark Model Calculations Of Symmetry Breaking in Parton Distributions

摘要： 使用夸克模型，我们计算核子价夸克分布中的对称性破缺效应。 特别是，我们研究了颜色磁效应导致的夸克模型SU(4)对称性的破缺，并发现颜色磁性为比值$d_V(x)/u_V(x)$偏离$1/2$提供了解释。 此外，我们计算了质子和中子价夸克分布中的电荷对称性破缺效应，并发现，与其它作者不同，这种效应太小，无法在实验中观察到。 显示英文摘要

摘要： Using a quark model, we calculate symmetry breaking effects in the valence quark distributions of the nucleon. In particular, we examine the breaking of the quark model SU(4) symmetry by color magnetic effects, and find that color magnetism provides an explanation for deviation of the ratio $d_V(x)/u_V(x)$ from $1/2$. Additionally, we calculate the effect of charge symmetry breaking in the valence quark distributions of the proton and neutron and find, in contrast to other authors, that the effect is too small to be seen experimentally.