Nuclear parton distributions and structure functions

束缚核子的部分子分布和结构函数不同于自由核子的情况。我们定量地评估了这些介质效应，并对几个核目标进行了计算。在模型计算中，我们采用Nambu-Jona-Lasinio（NJL）模型将核子描述为3夸克束缚态.核物质和有限核是在平均场近似下描述的，考虑到核子的内部夸克结构。核介质中的部分子分布由单个核子中的部分子分布与介质中的核子分布卷积而得。利用这种方法，我们预测了几种核的自旋相关部分子分布，并指出了介质修正的重要性。我们还评估了核部分子分布的味道依赖性，并将我们的结果应用于核目标的深非弹性中微子散射（NuTeV实验）和宇称违反电子散射。我们的主要结论之一是著名的NuTeV异常问题可以通过考虑部分子分布的介质修正来解决。对于碎裂函数的描述，我们也使用了NJL模型。我们描述了半包容性的高能散射过程中的π生产，考虑到多重碎裂过程的框架内的喷流模型。我们比较了我们的结果与最近的分析半包容π介子生产数据，并指出了多重碎裂过程的重要作用。

The parton distributions and structure function of a nucleon bound in the nucleus are different from the case of a free nucleon. We assessed these medium effects quantitatively, and performed calculations for several nuclear targets. We also evaluated the fragmentation functions, which describe meson production in deep inelastic scattering processes.For our model calculations, we used the Nambu-Jona-Lasinio (NJL) model to describe the nucleon as a 3-quark bound state. Nuclear matter and finite nuclei were described in the mean field approximation, taking into account the internal quark structure of the nucleons. The parton distributions in the nuclear medium were obtained by a convolution of the parton distributions in the single nucleon and the nucleon distributions in the medium. Using this method, we predicted the spin-dependent parton distributions for several nuclei, and pointed out the importance of medium modifications. We also assessed the flavor dependence of the nuclear parton distributions, and applied our results to deep inelastic neutrino scattering from nuclear targets (NuTeV experiment) and parity-violating electron scattering. One of our main conclusions was that the famous problem of the NuTeV anomaly can be solved by taking into account the medium modifications of parton distributions.For the description of the fragmentation functions we also used the NJL model. We described pion production in semi-inclusive high energy scattering processes, taking into account the multifragmentation processes in the framework of the jet-model. We compared our results with recent analyses of semi-inclusive pion production data, and pointed out the important role of the multifragmentation processes.