arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0902.4446hep-ph
收藏

魅力企鹅与夸克-强子对偶

Penguins with Charm and Quark-Hadron Duality

M. Beneke, G. Buchalla, M. Neubert, C. T. Sachrajda

摘要:

过程$B\to X_s l^+l^-$的综合分支分数主要由来自窄粲偶素状态的共振背景决定,例如$B\to X_sψ\to X_s l^+l^-$,其超过非共振粲环贡献两个数量级。本文从夸克-强子对偶性的普遍期望出发,讨论了这一事实的起源。$B\to X_s l^+l^-$中的情况与两体强子B衰变的$B\toππ$类型中的粲企鹅振幅进行了对比,证明了共振效应和潜在的非微扰$c\bar c$阈值区域不会使QCD因子分解的标准图像无效。不管粲夸克被当作轻夸克还是重夸克,这都成立。

英文摘要:

The integrated branching fraction of the process $B\to X_s l^+l^-$ is dominated by resonance background from narrow charmonium states, such as $B\to X_sψ\to X_s l^+l^-$, which exceeds the non-resonant charm-loop contribution by two orders of magnitude. The origin of this fact is discussed in view of the general expectation of quark-hadron duality. The situation in $B\to X_s l^+l^-$ is contrasted with charm-penguin amplitudes in two-body hadronic B decays of the type $B\toππ$, for which it is demonstrated that resonance effects and the potentially non-perturbative $c\bar c$ threshold region do not invalidate the standard picture of QCD factorization. This holds irrespective of whether the charm quark is treated as a light or a heavy quark.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑