Perturbative QCD and New Development of Spin Physics

本研究计划针对高能自旋物理的新发展，在微扰QCD框架下，利用算符乘积展开（OPE）和重整化群，以及由DGS型演化方程描述的部分子图像，对高能自旋物理进行了研究。第一年我们研究了极化正负电子碰撞测量的光子自旋结构函数g_1和极化虚光子中夸克和胶子的自旋相关部分子分布，达到了QCD的次领先对数级。在这方面，我们已经表明，部分子分布依赖于因式分解方案以及基于实际微扰计算的每个方案的特征，在高阶微扰理论。另一方面，在该研究项目的第二年和第三年（最后），我们澄清了高扭转效应，特别是存在的影响 ...更多信息 Pears认为twist-3效应是偏振虚光子的g_2结构函数。我们首先用QED盒图计算说明了这一点，然后对纯QED相互作用的情况进行了OPE分析。我们进一步将这个结果推广到包括QCD相互作用的情形，特别是g_2结构函数的精确三阶矩达到了首对数级，以及味非单态部分的x依赖性的大N_c极限。在O（4）展开和Nachtmann矩的框架下，我们研究了虚光子八个结构函数的正性约束和虚光子靶的靶质量效应.在目前的研究过程中，与相关领域人士的讨论和交流非常有益。特别感谢与东京大学、广岛大学、横滨国立大学、理研所、DESY等研究机构的交流。我们已经在JPS会议和国内外研究机构的国际研讨会上发表了我们的结果。这些结果已发表在上述期刊上。少

In the present research project, we have investigated the high-energy spin physics aiming at its new development, based on the framework of the perturbative QCD, utilizing the Operator Product Expansion (OPE) together with the renormalization group as well as the parton picture described by the DGLAP type evolution equation. In the first year, we have studied the spin structure function g_1 of the photon measured by the polarized electron-positron collision and the spin-dependent parton distributions of the quark and gluon inside the polarized virtual photon, to the next-to-leading-log order of QCD. In this respect, we have shows that the parton distributions depend on the factorization scheme as well as the characteristic features of each scheme based on the actual perturbative calculation, in the higher-order of the perturbation theory. On the other hand, in the second and the third (last) years of this research project, we clarified the higher-twist effects, especially that there ap … More pears the twist-3 effect is the g_2 structure function of the polarized virtual photon. We have shows this first by the QED Box diagram calculation and then the OPE analysis for the case of pure QED interaction. We further extruded this result to the case including the QCD interaction, in particular, the exact third moment of g_2 structure function to the leading-log order as well as the large N_c limit of the x dependence of the flavor-nonsinglet part. We also investigated the positivity constraint on the eight structure functions of the virtual photon and intiated the target mass effects of virtual photon target in the framework of O(4) expansion and Nachtmann moments. In the course of the present research, discussions and communications with the people in the related fields were very useful. Especially, we are very much indebted to the communications with the researchers at University of Tokyo, Hiroshima University, Yokohama National University, RIKEN and DESY. We have published our results at JPS meeting and the international workshops at the domestic as well as foreign research Institutes. These results have been published in the journals listed above. Less