QCD study of B meson decays: investigation of dynamical gluon effects inside B meson

B介子衰变的QCD研究：B介子内部动态胶子效应的研究

• 批准号: 16540266
• 负责人: TANAKA Kazuhiro
• 金额: $ 1.86万
• 依托单位: Juntendo University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540266/
• 关键词: B meson; decay; QCD; light-cone wave function; shape function; heavy quark; gluon; HQET; 重いクォーク; B meson; decay; QCD; light-cone wave function; shape function; heavy quark; gluon; HQET; 重いクォーク

The lightcone wavefunction (WF) and the shape function (SF) for B meson are indispensable for theoretical calculation of B-meson decay rates. We developed systematic investigation of WF and SF based on QCD, including effects induced by dynamical gluons inside B meson. We computed QCD radiative corrections for WF and SF, respectively, inserting the corresponding operators into off-shell Green functions. Our results reproduced the singular behavior, noticed in the literature, and revealed: the singular behavior arises not only for on-shell but also for off-shell cases; the structure of ultra-violet divergence is completely different from that of infra-red divergence; the relevant infra-red behavior is associated with "soft modes", as matrix elements of local operators. Based on this observation, we performed the decomposition of WF, SF into the short-and long-distance components, using the operator product expansion. The short-distance Wilson coefficients are calculated to one-loop accur … More acy in the MS-scheme, while the long-distance components are expressed by a complete set of local operators. Using QCD equations of motion, the operators of dimension five and six can be exactly reexpressed in terms of explicit dynamical gluon, i.e., as the quark-antiquark-gluon operators, whose matrix elements were already estimated from QCD sum rules. The Wilson coefficients contain the double logarithms of renormalization scale; namely, taking dynamical gluon effects into account, the WF, SF are governed by the "two-step" renormalization-group evolution, associated with the cusp anomalous dimension, and with the anomalous dimensions of local operators. (Before completing research, Professor Kodaira died suddenly. Because of this great loss, some of this research are yet unpublished or unsolved. These will be completed by the head investigator.) As other model cases where dynamical gluons play essential roles. we paid attention to mechanisms associated with dynamical gluons in hard processes with polarized hadron beams, and developed the corresponding QCD predictions. Less

B Meson的LightCone波函数（WF）和形状函数（SF）对于B-Meson衰减速率的理论计算是必不可少的。我们基于QCD开发了WF和SF的系统投资，包括由B Meson内部动态振荡引起的效果。我们分别为WF和SF计算了QCD辐射校正，将相应的运算符插入了脱离绿色函数中。我们的结果再现了文献中注意到的奇异行为，并揭示了：奇异行为不仅是出于壳的，而且是针对脱壳案件而产生的。紫外线差异的结构与红外差异完全不同。相关的红外行为与“软模式”有关，作为本地运营商的矩阵元素。基于此观察，我们使用操作员产品扩展将WF，SF分解为短距离组件。短距离威尔逊系数计算为单循环的精度……在MSCheme中更具acy，而长距离组件则由完整的本地运算符表达。使用QCD运动方程式，可以通过显式动态gluon（即，作为Quark-Antiquark-Gluon运算符，其矩阵元素已经从QCD总规则估算出来的Quark-Antiquark-Gluon运算符。威尔逊系数包含重新归一化量表的双对数；也就是说，考虑到动态的臀肌效应，WF，SF受“两步”的重新归化组进化的控制，与尖尖异常的尺寸以及与地方操作员的异常维度相关联。 （在完成研究之前，Kodaira教授突然去世了。由于这种巨大的损失，一些研究尚未出版或未解决。这些研究将由首席调查员完成。我们注意与具有极化强子梁的硬过程中与动态臀肌相关的机制，并开发了相应的QCD预测。较少的