Bc->kK衰变中的QCD效应分析
一直以来，尽管人们已经在实验和理论上做出了各种努力，标量粒子的内部结构不为世人所了解。在本文中，我们基于朴素的两夸克结构假设，利用PQCD因子化方法分析 弱衰变过程，以期为理解轻标量介子的动力学内容提供理论指导。文章绪论中，介绍相关研究背景。第二章，介绍轻标量介子和PQCD方法，并给出了Bc介子，轻标量，赝标量的波函数和分布振幅。在三，四章中通过对 衰变过程的分支比进行计算，分析其非微扰和微扰 贡献，得到一些结论。论文结尾部分,作者对全文进行了概括并作展望。
毕业论文关键词: PQCD因子化法 介子衰变 分支比
Analysis of QCD impacts in the decays
In 1998, the CDF Collaboration found the first semileptonic Bc meson decay, then both D0 and CDF Collaborations found the first hadronic decay of Bc meson. The LHC has run since the end of 2009. It provided to the scientists with more samples of Bc meson decays. In this April, LHC began a new run with higher energy after the inspection, which will provide strongly experimental basis to us for further understanding the Bc meson physics. At the theoretical aspect, studies on Bc meson decays can help us to test the standard model, understand the QCD and perturbative QCD dynamics, and investigate new physics beyond the standard model. Therefore, Bc meson decays are very important.
All along, the internal structure of scalar particles was not well understood, although many efforts have been made theoretically and experimentally. In this dissertation, we study the decay process with the pQCD factorization approach based on the two-quark assumption, in order to provide the theoretical guides to understand the dynamics of light scalar mesons. First, the author gives a brief introduction to scalar meson, pQCD factorization approach, and the related meson wave functions. The author calculates the branching ratio of the decays numerically and analyzes the QCD and pQCD effects phenomenologically in the third and fourth part. Then we can obtain some interesting conclusions. At the end of the paper , the author summarizes the main contents and makes an outlook.
Keywords : factorization approach meson decay branching ratio
目录
摘要 i
Abstract ii
第一章 绪论 1
第二章 微扰QCD因子化方法、理论框架及介子波函数 2
2.1 微扰QCD因子化方法 2
2.2 理论框架 2
2.3 介子波函数 3
第三章 微扰QCD因子化方法下的解析计算 6
第四章 结果与分析 9
4.1 输入参数 9
4.2 结果及分析 9
第五章 总结与展望 12
致谢 13
参考文献 14
第一章 绪论
粒子物理标准模型是量子色动理论[1]和电弱统一模型[2]一同构成的，并且在过去的几十年里取得了巨大的成功[3]，例如在 实验中被精确检验, 但是标准模型并不能解释质量起源问题以及为何会有19个参数。LHC发现了疑似希格斯玻色子的粒子，这预示着标准模型理论的巨大成功。