标题： 核子结构函数的卷积模型 显示英文标题

标题： Convolution Model for the Structure Functions of the Nucleon

摘要： 我们从一个MIT-bag模型计算开始，该计算提供了关于核子中组成夸克分布的信息。 然而，组成夸克本身被视为复杂对象，其部分子结构在深度非弹性散射中被解析。 这导致了组成夸克的结构函数，在非极化情况下，这些结构函数通过使用三个模型参数在固定尺度上与数据拟合。 使用$Q^{2}$--演化方程，数据在其他尺度上也得到了很好的描述。 对于自旋相关的结构函数$g_{1}^{p,n}$，我们还需要为价夸克和海夸克引入极化函数，这些函数仅通过利用可用质子数据的$x$--依赖性来确定。 建议在范围$x\geq 0.01$内存在负极化的海。 然后我们能够预测中子结构函数$g_{1}^{n}$的形状，结果与实验高度一致。 最后，我们给出了横向极化的结构函数$g_{2}$的估计，提供了提取扭曲--3贡献并评估其重要性的可能性。 显示英文摘要

摘要： We start from an MIT-bag model calculation which provides information about the constituent quark distributions in the nucleon. The constituent quarks, however, are themselves considered as complex objects whose partonic substructure is resolved in deep inelastic scattering. This gives rise to structure functions of the constituent quarks which, in the unpolarized case, are fitted to data at a fixed scale employing three model parameters. Using $Q^{2}$--evolution equations the data are also well described at other scales. For the spin\-dependent struc\-ture func\-tions $g_{1}^{p,n}$ we additionally have to introduce polar\-izat\-ion functions for valence and sea quarks which are determined by exploiting the $x$--dependence of the available proton data only. A negatively polarized sea in the range $x\geq 0.01$ is suggested. We are then capable of predicting the shape of the neutron structure function $g_{1}^{n}$ which turns out to be in good agreement with experiment. Finally we present an estimate for the trans\-versely polarized structure function $g_{2}$, offering the possibility of extrac\-ting the twist--3 con\-tri\-bution and rating its importance.