B介子衰变振幅的精确计算及相关新物理的探讨

重味物理尤其是B物理是粒子物理研究中的前沿课题之一。现运行的LHCb与即将运行的Belle II实验将为精确检验粒子物理标准模型及理解重夸克衰变的强相互作用机制等提供了宝贵的契机。本项目将密切联系格点 QCD 等方法，选择理论研究中几个关键且难度系数较大的问题进行攻关，包括：1) 结合格点计算，首次给出B介子LCDA等参数；利用有效理论方法，研究两介子分布振幅；2)计算遍举B介子衰变振幅的幂次修正，从有效场论出发，构建合适的QCD因子化定理，深入理解幂次修正的因子化特性；3)进一步深化B介子衰变的唯象研究，建立适用于多体B介子的因子化定理；基于目前B物理中“反常现象”并结合LHC实验，分析新物理效应。这些研究的方法可应用至粲物理过程，为BESIII物理研究增加新的生命力；另一方面，本项目的突破可为未来CEPC/Z-Factory时代的重味物理理论研究提供新的参考。

Heavy quark physics in particular B physics is one frontier in particle physics research. The ongoing LHCb and forthcoming Belle II experiments provide an ideal platform to precisely test the standard model of particle physics and understand the underlying dynamics in the heavy quark decays. This research proposal will be focused on a few key problems in heavy flavor physics. They include: 1) the Lattice QCD simulation of the B meson quasi LCDA, which allows us for the first time to fully understand the B meson LCDA; the derivation of two-meson generalized LCDA using the chiral perturbation theory; 2)power corrections in exclusive decays of B meson and others; 3)phenomenological study of B decays, including multi-body B decays, and other new important processes; the analysis of new physics effects based on the B physics anomaly like B->K*l+l-. The progress in this proposal can be applied to investigate the anomalies that could be studied at BESIII, even though the concerned energy for charm is much lower. Moreover our study would provide very valuable references for analyzing the data obtained by the future CEPC/Z-factory.