基于因子化的拓扑图振幅方法研究重味强子弱衰变

重味强子弱衰变对于精确检验标准模型、加深理解强相互作用、研究CP破坏现象具有重要意义。在理论计算上因强子非轻衰变会涉及低标度的QCD效应，我们难以直接对其进行微扰计算。随着近年来Belle(II)、LHCb以及BESIII等实验的进展，我们考虑结合实验解决上述困难。基于因子化的拓扑图振幅方法(FAT)正是这种利用实验数据来整体拟合非微扰QCD贡献的方法，因而它是模型无关的，并且在FAT方法中我们考虑了所利用的SU(3)味对称性的破坏效应，从而减少相应的理论误差以及使得结果最大程度地不依赖于理论参数的输入。. 本项目将采用FAT方法研究重味强子的两类衰变：一是双粲B介子两体非轻衰变。通过精确抽取其中企鹅图和湮灭图贡献，研究其CP破坏现象，精确检验标准模型；二是粲重子Λc两体非轻衰变。理解重子弱衰变动力学机制，预言其CP破坏量，为实验上寻找重子的CP破坏提供参考。

Non-leptonic heavy hadron decays are of importance for testing the Standard Model (SM), understanding of strong interaction and studying CP violation. Theoretically it’s difficult to calculate them in QCD inspired approaches as they involve nonperturbative QCD dynamics. Fortunately Belle(II), LHCb and BESIII have made great efforts in studying heavy hadron decays information in recent years. We try to resolve above problem by utilizing numerous data of branching fractions and CP asymmetries of them measured in experiments. Factorization-assisted topological amplitude approach is just the one to extract the nonperturbative QCD effects from experimental data, e.g. FAT is a model-independent approach. Furthermore, it has included flavor SU(3) breaking effect assisted by a factorization hypothesis. Thus the approximation of flavor SU(3) symmetry will not give rise to the uncertainties of results in FAT. Also It provides a framework with which we can do the least-dependent on parameters...The projects focused on the heavy hadron decays in FAT are included: (1)Studying the decays of B meson to two charmed mesons. We will fit the penguin contribution sensitive to CP asymmetry and annihilation contribution from experimental data. With fitted parameters, we predict their CP violation and test the SM. (2)Analysis of two-body hadronic decays of Λc into a light baryon and a pseudoscalar (or a vector). We expect to understand the mechanism of baryon decays and predict the CP violation in charmed baryon decays on theoretical side to help searching for them in experiment.