以“色允许”树图贡献为主的B介子的两体含粲衰变过程，由于没有企鹅图的污染，大大降低了理论预言中来自QCD动力学的不确定性，对于探索B介子的衰变机制有着重要的意义。在本项目中，我们基于k_T因子化定理，保留了部分子横向动量以消除端点奇异性。在微扰QCD的框架下，色允许树图、不可因子化图以及湮灭图贡献都可以微扰计算，其在预言B介子含粲衰变方面有着很大的理论优势。另外，我们考虑了一些重要的下一阶修正效应，如对四夸克算符的单圈修正等。将方法的精度提高到次领头阶水平，其理论预言更加可靠。这些研究对于检验因子化定理、估计SU(3)味对称性破坏、精确抽取碎裂函数f_d/f_s的比值 和寻找新物理迹象等方面都有一定的指导意义，在理论上和实验上都具有重要的学术价值。

The two-body charmed B decays for color-allowed dominant modes are no contribution from penguin diagrams, so that theoretical uncertainties involved in the relevant QCD dynamics become much less. Thus,these modes play an important role in studying B meson decay mechanisms.In this project,by employing the perturbative QCD approach based on k_T factorization, we keep the transverse momentum so that the end point singularity is regularized. The diagrams including color-allowed tree,nonfactorizable and annihilation type are all calculable perturbatively. It has a great theoretical advantage in predicting these modes.In addition, some important next-to-leading order contributions, such as the one-loop correction to four-quark operators and so on, are considered in order to improve the accuracies of the approach and the reliability of the theoretical predictions. The study is instructive to test the factorization hypothesis, to estimate the flavor SU(3) symmetry breaking effects, to extract the ratio f_d/f_s of fragmentation functions precisely and to search the signals of new physics and hence has great.academic value both on the theoretical and experimental sides.