Study Of B_s�'η_c (J/ψ)D Decay With Perturbative QCD Approach

With the advent of LHCb, many B decay modes can be studied in detail. It is estimated that about5.9×108Bs mesons are collected per year in the SuperKEKB. More and more Bs decays will make the Standard Model and new physics subject to a series of increasingly stringent tests, through observables such as branching ratios, CP-violationg asymmetries and kinematic distributions.The W-exchange processes Bs�'ηc(J/ψ)D are studied with the perturbative QCD (pQCD) approach. Firstly, we introduce the basic theory for the study of B meson decays—the low energy effective theory. Then, we discuss the present methods for the hadronic matrix elements. And we dwell on the perturbative QCD approach.Our major work is presented in the chapter three. We study the Bs�'ηc(J/ψ)D process with the pQCD method. In our study three kinds of wave functions of Bs mesons and two forms of wave functions of ηc(J/ψ) mesons are considered. It is found that the decay processes in question are dominated by hard gluon exchange. The perturbative QCD approach is applicable to BsBs�'ηc(J/ψ)D processes. We analysis the contributions of WFs ΦB/+and ΦB/-, twist-2and twist-3WFs of ηc(J/ψ) mesons, and also contributions from different topologies. The the branching ratios of BsBs�'ηc(J/ψ)D decay are estimated.Our study shows the branching ratios for BsBs�'ηcD,ηcD, J/ψD, J/ψD decays are the order of10-7,10-8,10-8,10-9, respectively. We also investigate the uncertainties from the shape parameters and hard scales. It is found that the largest uncertainty is mainly from the meson wave function.