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

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 Because of this great loss, some of this research are yet unpublished or unsolved.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介子的光锥波函数（WF）和形状函数（SF）是B介子衰变率理论计算中不可缺少的。我们系统地研究了基于QCD的WF和SF，包括B介子内部动态胶子的效应。我们分别计算了WF和SF的QCD辐射校正，并将相应的算子插入off-shell Green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出现在壳上，也出现在壳外；紫外散度的结构与红外散度的结构完全不同；相关的红外行为与“软模式”相关联，作为局部算子的矩阵元素。在此基础上，我们利用算子积展开，将WF、SF分解为短分量和长分量。在ms方案中，短距离威尔逊系数的计算精度达到单环精度，而远距离威尔逊系数则由一组完备的局部算子表示。利用QCD运动方程，第5维和第6维的算符可以精确地用显式动态胶子表示，即夸克-反夸克-胶子算符，其矩阵元素已经由QCD求和规则估计出来。Wilson系数包含重整化尺度的双对数；即考虑动态胶子效应，WF、SF受“两步”重整化群演化控制，与尖端反常维数和局部算子的反常维数相关。(在完成研究之前，小平教授突然去世了。由于这个巨大的损失，一些研究尚未发表或未解决。这些将由首席研究员完成。)在其他模型中，动态胶子起着至关重要的作用。我们关注了极化强子束硬过程中动态胶子的相关机制，并建立了相应的QCD预测。少

项目成果

QCD prediction of A_<TT> for small Q_T dimuon production in pp and p anti-p collisions

pp 和 p 反 p 碰撞中小 Q_T dimuon 产生的 A_<TT> 的 QCD 预测

• 发表时间: 2007
• 期刊: American Institute of Physics Conference Proceedings 915(印刷中)
• 作者: T.Kai;H.Kozaki;K.Nakao;Y.Nambu;W.Bentz;Hiroyuki Kawamura
• 通讯作者: Hiroyuki Kawamura

Radiative corrections and enhanced power corrections for the shape function in inclusive B decays

包含 B 衰变中形状函数的辐射校正和增强功率校正

• 发表时间: 2006
• 期刊: Nuclear Physics B (Proc.Suppl.) 157
• 作者: H.Fukaya;T.Onogi;S.Hashimoto;T.Hirohashi;K.Ogawa;H.Kawamura
• 通讯作者: H.Kawamura

The dilepton Q_T spectrum in transversely polarized Drell-Yan process in QCD

QCD中横向偏振Drell-Yan过程中的双轻子Q_T谱

• 发表时间: 2006
• 期刊: Progress of Theoretical Physics 115・No.3(掲載予定)
• 作者: S.Negishi;H.Matsufuru;T.Onogi;T.Umeda;H.Kawamura;若松 正志;K.Terasaki;H.Kawamura
• 通讯作者: H.Kawamura

A new approach for single transverse-spin asymmetries from twist-3 soft-gluon mechanism

Twist-3软胶子机制单横向自旋不对称的新方法

• 发表时间: 2007
• 期刊: American Institute of Physics Conference Proceedings 915(印刷中)
• 作者: A.I.Titov;A.Hosaka;S.Date;Y.Ohashi;O.Yasuda;W.Bentz;Yuji Koike
• 通讯作者: Yuji Koike

Unravelling Soft Components in the Shape Function for Inclusive B Decays

解开包含 B 衰变的形状函数中的软分量

• 发表时间: 2005
• 期刊: Progress of Theoretical Physics 113
• 作者: S.Nishida;T.Iijima et al.;T.Fujihara;T.Fujihara;H.Kawamura
• 通讯作者: H.Kawamura