Study Of B Meson Two-boday Non-leptonic Decays With Perturbative QCD Approach

The Standard Model(SM) is a basic theory, which describes strong, weak and electromagnetic interaction and it has achieved great success. Along with the prosperous running of the two B meson factories in the United States and Japan, B meson physics has become an important research field. Especially the study of B meson decays, which can not only provide us a lot of information for testing the standard model, but also build a platform for researching the new physics beyond SM.Because the B meson decays have important scientific status in the field of B physics, people made a lot of exploring and managed to find many case of B meson decays. However, many confusion remain unresolved, the most headaching is about theB~0→π~0π~0 decays in the B meson two-body non-leptonic decays. It is also called“pp ” puzzle and the essence is the branching rations of the theoretical results are much smaller than the experiment. Before this, theorists had estimated the branching ratio and CP asymmetry of B~0→π~0π~0 decays by different methods(such as perturbative QCD approach). Recently, some other scholars have recalculated this branching ratio and their work have take the next-to-leading-order(NLO) contributions from various sources into consideration in the PQCD factorization approach. But all this results are not consistent with the latest experimental data. Therefore, we revisit theB~0→π~0π~0 dacays by the p QCD approach, hoping the accuracy can be improved.In this paper, starting with the perturbative QCD method, we revisit and analyze theB~0→π~0π~0 decays. Firstly, we introduce the basic theory for the study of B meson decay and describe the perturbative QCD approach in detail. Secondly, the research section shows our work in detail. From the stand of energy, i.e. The low-energyeffective Hamiltonian theory of B meson decay, and using the PQCD approach based on thek_T factorization, we divided the convolution of the decay amplitude into three part:wave functions, solid-scattering nuclei and Wilson coefficient respectively. In this progress factorization, light-cone coordinate, Sudakov factor are act usefull and have very importantly. We consider all the possible diagrams including non-factorizable contributions and annihilation contributions, and identity principle is also taken into account. Finally, we obtain the averaged branching ratio of theB~0→π~0π~0 decay, and only to find this result is consistent with the Belle and HFAG results. we also forecast the CP asymmetry ofB~0→π~0π~0 decay, which would be a good theoretical basis for the experimental research on this decay in the future.