Quark-parton models and hadron structure

1.Q^2发展方程我们开发了一个求解Altarelli-Parisi Q^2发展方程的计算机程序。首先，研究了拉盖尔多项式方法。我们发现，只需20个多项式就足以获得准确的演化结果。接下来，研究了一种蛮力方法。在这种方法中，将变量x和q^2分成小步，然后简单地计算微分和积分。我们发现，要得到准确的结果，需要2000个x步长和200个q^2步长。通过与实验数据的比较，我们明确地表明高扭转效应在小Q^2区域是重要的。将该方法应用于极化结构函数g_1.2。在核子[(u-d)_A，F_&lt；A(1)3&gt；(X)]中考虑部分子复合效应的情况下，我们发现不明确的相互作用可以产生有限的u-d分布，即使它消失在核子中。因此，我们在比较不清楚的Drell-yan数据和NMC数据时必须谨慎。其次，采用两种不同的描述方法：部分子复合模型和定向喷流模型，研究了F_3结构函数中的阴影现象。我们发现它们在小x处给出了非常不同的预测，因此它们可以被未来的实验所检验。3.反夸克分布u-d在核子NMC发现的Gottfred和规则违犯中表明了u和d之间的差异。关于这个主题发表了许多论文。我写了一篇总结论文，并将其提交给物理报告。

1.Q^2 evolution equation We developed a computer program for solving the Altarelli-Parisi Q^2 evolution equations. First, a Laguerre-polynomial method is studied. We find that merely twenty polynomials are enough for obtaining accurate evolution results. Next, a brute-force method is investigated. In this method, the variables x and Q^2 are divided into small steps, then differentiation and integration are simply calculated. We find that 2000 x steps and 200 Q^2 steps are necessary for getting accurate results. We explicitly showed that higher-twist effects are important in the small Q^2 region in comparison with experimental data. The method was applied to the polarized structure function g_1.2.Parton distributions in nuclei [(u-d)_A, F_<A(1)3>(x)] Considering parton recombination effects in a uncleus, we find that unclear interactions could create a finite u-d distribution even it vanishes in the nucleon. Therefore, we have to be careful in comparing unclear Drell-Yan data with the NMC data. Next, shadowing in the F_3 structure function is investigated by using two different descriptions : parton-recombination and aligned-jet models. We find that they give very different predictions at small x, so that they could be tested by future experiments.3.Antiquark distribution u-d in the nucleon NMC finding of the Gottfried sum rule violation indicated the difference between u and d. Many papers are published on this topic. I wrote a summary paper and submitted it to Physics Reports.