Nuclear parton distributions and structure functions

束缚在原子核中的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，并对几个核靶进行了计算。在我们的模型计算中，我们使用Nambu-Jona-Lasinio(NJL)模型将核子描述为3夸克束缚态。核物质和有限核在平均场近似下被描述，考虑了核子的内部夸克结构。通过将单核子中的部分子分布与介质中的核子分布进行卷积，得到了核介质中的部分子分布。利用这种方法，我们预测了几个原子核的自旋相关的部分子分布，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关系，并将我们的结果应用于核靶的深度非弹性中微子散射(NuTeV实验)和宇称破坏电子散射。我们的主要结论之一是，通过考虑部分子分布的介质修正，可以解决著名的NuTeV反常问题。对于碎裂函数的描述，我们也使用了NJL模型。我们在JET模型的框架下，考虑了多重碎裂过程，描述了半包含高能散射过程中的介子产生。我们将我们的结果与最近对半包含性π介子生产数据的分析进行了比较，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.