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arXiv 2302.13673hep-ph
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B介子三粒子分布与FCNC B衰变中的粲夸克圈

Three-particle distribution in B meson and charm-quark loops in FCNC B decays

Dmitri Melikhov

AI总结:

本文研究B介子三粒子Bethe-Salpeter振幅中粲夸克圈对FCNC B衰变振幅的非因子化贡献,证明重夸克极限下主导贡献由硬核与双共线光锥位形下3BS的卷积给出,并揭示了该位形下分布振幅的新约束。

摘要:

我们讨论粲夸克圈对通过B介子三粒子Bethe-Salpeter振幅(3BS)给出的FCNC B衰变振幅的非因子化(NF)贡献。该3BS包含一个重夸克场和两个轻场(一个轻夸克和一个胶子)。我们的讨论旨在阐明为正确描述粲夸克圈对FCNC B衰变振幅的贡献所必需的B介子3BS的性质。我们证明,在重夸克极限下,非因子化粲夸克对FCNC B衰变振幅的主导贡献由某个硬核与处于“双共线”光锥(LC)位形下的B介子3BS的卷积给出:其中一个轻自由度$ϕ(x)$,$x^2=0$,位于光锥的$(+)$方向,而另一个轻自由度$ϕ'(x')$,$x'^2=0$位于$(-)$方向。我们展示了对此双共线位形下参数化3BS的分布振幅所涌现出的新约束。

英文摘要:

We discuss a nonfactorizable (NF) contribution of a charm loop to the FCNC $B$-decay amplitude given through the three-particle Bethe-Salpeter amplitude (3BS) of the $B$-meson. This 3BS contains one heavy-quark field and two light fields (a light quark and a gluon). Our discussion is aimed at clarifying properties of the $B$-meson 3BS necessary to describe properly charm-loop contributions to the amplitudes of FCNC $B$-decays. We demonstrate that the dominant contribution of nonfactorizable charm to FCNC $B$-decay amplitude is given in the heavy-quark limit by a convolution of some hard kernel and the $B$-meson 3BS in a "double-collinear" light cone (LC) configuration: one of the light degrees of freedom $ϕ(x)$, $x^2=0$, lies on the $(+)$-direction of the LC, whereas another light degree of freedom $ϕ'(x')$, $x'^2=0$ lies on the $(-)$-direction. We show the emergence of new constraints on the distribution amplitudes which parametrize the 3BS in this double-collinear configuration.

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。

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