Pqcd Program Double Higgs Model With B_s �� Pp Decay Process

As is well known, the theoretical studies and experimental measurements of the two-body charmless hadronic B and Bs meson decays provide a good opportunity for testing the standard model (SM), probing CP violation and searching for possible new physics(NP) beyond SM. Actually the comprehensive studies of the B meson system in the framework of the standard model have been undertaken frequently by using different factorization methods. In this paper, by employing the pQCD factorization, we calculated the new physics contributions, in the two-Higgs-doublet models, to the branching ratios and CP-violating asymmetries of Bs�'PP decays.In the review part of this thesis, we firstly discussed the main problems of the standard model(SM) and introduced the motivation for building the new physics models. A brief summary of the theoretical frameworks of the standard model and the two-Higgs-doublet-models(2HDMs) were then given in the second chapter. In chapter three, we gave a mini-review about the theoretical framework of B Physics, presented the main points of the pQCD factorization approach to be used in this thesis.Chapter four is the part of our own work. We evaluated the new physics contributions to the the Wilson coefficients Ci(mb) in the third type of 2HDM, and found that the NP corrections to Ci(i=3,…,10) are very small in magnitude and can be neglected safely, but the NP contributions to the Wilson coefficient C8g can be rather large.Also in chapter four, we studied the NP contributions to the 13 Bs�'P2P3 decays, and made some discussion about these channels. For the branching ratios of those chan-nels, only two of them have been measured experimentally. The NP contributions can be help in order to make the theoretical predictions becoming consistent with the cur-rent date. We found numerically that:(a) the NP contributions are very small for those channels without the contributions coming from the chromo-magnetic penguin diagrams. (b) for those O8g-dominated decay modes, the 2HDMⅢcontributions can provide an enhancement about 30%～190% to their branching ratios.In chapter four, we also calculated the CP-violating asymmetries of the considered decays in the SM and the 2HDMⅢ. We found that (a) Compared with the SM pre-diction, in the four decay channels without chrorao-magnetic penguin diagrams, the NP contributions are also generally small. (b) In other decays, besides Bs�'K+π-, the NP on direct CP-violations tend to make the SM predictions decreased. The largest correc-tion is about -57% for decay Bs�'K+K-. (c) Only for Bs�'K+π-, the NP correction can make an increase of 24% respect to the SM prediction.Lastly, in chapter four, we also calculated the mixing-induced CP violation parameters Sf and Hf. For all decays, the 2HDMⅢcorrections to both the Sf and Hf are small or moderate.In the last chapter, we gave a short summary of this thesis and some remarks on future developments of B physics in coining years.