The semileptonic decays of B/Bs meson in the perturbative QCD approach： a short review

In this short review, we present the current status about the theoretical and experimental studies for some important semileptonic decays of B/Bs mesons. We firstly gave a brief introduction for the experimental measurements for B/Bs → P（l＋l-, l-v-l, vv-） decays, the BaBar＇s R（D） and R（D＊） anomaly, the P′5 deviation for B0→ K＊0μ＋μ decay. We then made a careful discussion about the evaluations for the relevant form factors in the light-cone QCD sum rule, the heavy quark effective theory, and the perturbative QCD factorization approach. By using the form factors calculated in the perturbative （pQCD） approach, we then calculate and show the pQCD predictions for the decay rates of many semileptonic decays of B/Bs mesons. We also made careful phenomenological analysis for these pQCD predictions and found, in general, the following points： （a） For all the considered B/Bs semileptonic decays, the next-to-leading order pQCD predictions for their decay rates agree well with the data and those from other different theoretical methods; （b） For R（D） and R（D＊）, the pQCD predictions agree very well with the data, the B aBar＇s anomaly of R （D（＊）） are therefore explained successfully in the standard model by employing the pQCD approach; and （c） We defined several new ratios RD^l,τ and RDs^l,τ, they may be more sensitive to the QCD dynamics which controls the B/Bs→（D（＊）, Ds（＊）） transitions than the old ratios, we therefore strongly suggest LHCb and the forthcoming Super-B experiments to measure these new ratios.     

微扰QCD方法下的B→Ds^（＊）ρ（ω）衰变

在微扰QCD因子化方法的框架下计算了B→Ds^（＊）ρ^0,B＋→Dx^（＊）＋ρω^0和B^0→Ds^（＊）ρ-衰变道的分支比．通过计算发现衰变道B→Ds^（＊）＋ρ^0,B^＋→Ds^（＊）＋ω^0和B^0→Ds^＋ρ^-的分支比在10^-5量级,而B^0→Ds^（＊）＋ρ^-衰变道的分支比最大,约为1．2×10^-4．在这些衰变道中,对于末态包含两个矢量介子的衰变,径向激化的贡献是主要的,并且大于80％;而两个横向激化的贡献是被rDs^（＊）,rρ（ω）的幂次压低的．     

The two-body hadronic decays of Bc meson in the perturbative QCD approach： a short review

Along with the running of Large Hadron Collider （LHC） located at CERN in November 2009, a large number of data samples of Bc meson have been collected and some hadronic Bc decay modes have been measured by the LHC experiments. In view of the special and important roles of Bc meson decays playing in the heavy flavor sector, we here give a short review on the status of two body hadronic decays Bc→M1M2 at both experimental and theoretical aspects. For the theoretical progresses, specifically, we will show lots of theoretical studies on two body hadronic Bc decays involving pseudoscalar, vector, scalar, axial-vector, even tensor meson（s） in the final states by employing the perturbative QCD （pQCD） factorization approach. We will present a general analysis about the two- body hadronic decays of the heavy Bc meson and also provide some expectations for the future developments.     

微扰QCD方法下的B→D_s~(*)ρ(ω)衰变(英文)

在微扰QCD因子化方法的框架下计算了B+→Ds(*)ρ0,B+→Ds(*)ω0和B+→Ds(*)+ρ-衰变道的分支比.通过计算发现衰变道B+→Ds(*)+ρ0,B+→D(s*)+ω0和B0→Ds(*)+ρ-的分支比在10-5量级,而B0D(s*)+ρ-衰变道的分支比最大,约为1.2×10-4.在这些衰变道中,对于末态包含两个矢量介子的衰变,径向激化的贡献是主要的,并且大于80%;而两个横向激化的贡献是被rDs(*)、rρ(ω)的幂次压低的.