Phenomenological Studies Of New Physics Z’Effects On Two-body Charmless Hadronic B_s-meson Decays

Heavy flavor physics, especially the B physics, are of crucial importance to test the Standard Model (SM), pursue the origin of the CP violation and search for signals of New Physics (NP). B physics is a perfect region for studying the CP violation. So, the study of B-meson decays is one of the currently very active researching fields.At present, the QCD factorization approach is used widely to calculate the non-perturbative part (saying the hadronic matrix elements) of B-meson decays. As is well-known, within QCDF framework, the estimates of the hard-spectator and annihilation corrections, which are numerically important to evaluate the observables, always suffer from end-point divergency. To calculate the hadronic matrix elements, we use the Corn-wall prescription of the infrared finite gluon propagator by introducing a dynamical mass of gluon to avoid enhancements in the soft endpoint region. In this thesis, some basic con-cepts, theoretical tools relevant to B-meson decays (such as the CKM matrix and unitarity triangle, the CP-averaged branching fractions, various CP violations and polarization frac-tions, the renormalization group, the operator product expansion and low-energy effective Haniltonian describing B-meson decays, finally some schemes employed to calculate the hadronic matrix elements including the QCD factorization approach used in the thesis) and the introduction of a family non-universal Z’ model are briefly summarized in the first three chapters. Then, we present the main body of the thesis, which is composed of the following parts:Firstly, motivated by the up-to-date experimental data, we revisit the Bs�'KK(*) decays within QCDF formalism with two schemes (the phenomenological parameterization and the finite gluon propagator) to deal with the end-point divergency in hard spectator and annihilation corrections, and evaluate the effects of a family non-universal Z’ boson on these decays. We find that the two schemes present different predictions for some observ-ables, such as Acp/dir(Bs�'K+K*-), which could be judged by the future accurate measure-ments. Within a family non-universal Z’ model, the observables could be easily enhanced or reduced by the Z’ contributions. In addition, With the well measured observables of Bd/o�'π+K-decay as constraints, in the limit of U-spin symmetry, the branching fraction and direct CP asymmetry of Bs�'K+K-decay are seriously restricted to [27,33] x10-6and [-16.4%,-8.1%], respectively. Based on the above work, using the QCD factorization approach, we present a detailed investigation for two-body hadronic charmless Bs meson decays to two vectors mesons. The up-to-date experimental data of Bs�'ππ, K*0K*0decays data are not consistent with the present theoretical predictions. In order to remove the discrepancy, We pursue possible solutions within QCDF formalism with the infrared finite gluon propagator to deal with the end-point divergence in hard spectator and annihilation corrections and within a family non-universal Z’ model. We find B(Bs�'ππ) can be explained within QCDF formalism with the infrared finite gluon propagator. With the Z’ parameters from the constraint by Bs-Bs mixing and Bu,d�'πK decays, our predictions for B(Bs�'ππ,K*0K*0) are all consistent with the available experimental data within errors. However, the predictions for the polarization fractions deviate from the experimental data, too. Moreover, Bs�'ΦΦ,Φρ, ωΦ decays are sensitive to the Z’ contributions and are very suitable to probe NP model.