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Charmless B(s) → VV Decays in Factorization-Assisted Topological-Amplitude Approach

Chao Wang; Qi-An Zhang; Ying Li; Cai-Dian LuSubjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Within the factorization-assisted topological-amplitude approach, we studied the 33 charmless B(s) → VV decays, where V stands for a light vector meson. According to the flavor flows, the amplitude of each process can be decomposed into 8 different topologies. In contrast to the conventional flavor diagrammatic approach, we further factorize each topological amplitude into decay constant, form factors and unknown universal parameters. By χ2 fitting 46 experimental observables, we extracted 10 theoretical parameters with χ2 per degree of freedom around 2. Using the fitted parameters, we calculated the branching fractions, polarization fractions, CP asymmetries and relative phases between polarization amplitudes of each decay mode. The decay channels dominated by tree diagram have large branching fractions and large longitudinal polarization fraction. The branching fractions and longitudinal polarization fractions of color-suppressed decays become smaller. Current experimental data of large transverse polarization fractions in the penguin dominant decay channels can be explained by only one transverse amplitude of penguin annihilation dia-gram. Our predictions of those not yet measured channels can be tested in the ongoing LHCb experiment and the Belle-II experiment in future. |

Subjects: Physics >> Nuclear Physics

Within the factorization-assisted topological-amplitude approach, we study the two-body charmed?B?meson decays?Bu,d,s→D(?)M, with?M?denoting a light pseudoscalar (or vector) meson. The meson decay constants and transition form factors are factorized out from the hadronic matrix element of topological diagrams. Therefore the effect of SU(3) symmetry breaking is retained, which is different from the conventional topological diagram approach. The number of free nonperturbative parameters to be fitted from experimental data is also much less. Only four universal nonperturbative parameters?χC,??C,?χE?and??E?are introduced to describe the contribution of the color suppressed tree and?W-exchanged diagrams for all the decay channels. With the fitted parameters from 31 decay modes induced by?b→c?transition, we then predict the branching fractions of 120 decay modes induced by both?b→c?and?b→u?transitions. Our results are well consistent with the measured data or to be tested in the LHCb and Belle-II experiments in the future. Besides, the SU(3) symmetry breaking, isospin violation and?CP?asymmetry are also investigated. |

Constrain the UT angle $\gamma$ by CP violation parameters in $B^0 \to \pi^+ \pi^-$

Qin Qin; Zhi-Tian Zou; Cai-Dian Lu; Ying LiSubjects: Physics >> Nuclear Physics

We calculate the tree and penguin amplitudes in the?B0→π+π??decay channel employing the perturbative QCD factorization approach. Using the amplitudes as input with the theoretical uncertainties sufficiently considered, we constrain the UT angle?γ?to?53?≤γ≤70?, from the measurements of the CP violation parameters?Cπ+π??and?Sπ+π??in?B0→π+π?. The U-spin breaking effect between?B0→π+π??and?B0s→K+K??is estimated to be around 30\%. |

Subjects: Physics >> Nuclear Physics

By assuming that the scalar meson?K?0(1430)?belongs to the first excited states or the lowest lying ground states, we study the pure annihilation-type decays?B→K?±0(1430)K(?)??in the QCD factorization approach. Within the standard model, the branching fractions are at the order of?10?8?10?7, which is possible to be measured in the ongoing LHCb experiment or forthcoming Belle-II experiment. We also study these decays in the family non-universal?Z′?model. The results show that if?mZ′≈600GeV?(ζ=0.02), both the branching fractions and?CPasymmetries of?B????0→K?+0(1430)K??could be changed remarkably, which provides us a place for probing the effect of new physics. These results could be used to constrain the parameters of?Z′?model. |

Study of $B \to K_0^*(1430)K^(*)$ decays in QCD Factorization Approach

Ying Li; Hong-Yan Zhang; Ye Xing; Zuo-Hong Li; Cai-Dian L╱Subjects: Physics >> Nuclear Physics

Within the QCD factorization approach, we calculate the branching fractions and?CP?asymmetry parameters of 12?B→K?0(1430)K(?)?decay modes under the assumption that the scalar meson?K?0(1430)?is the first excited state or the lowest lying ground state in the quark model. We find that the decay modes with the scalar meson emitted, have large branching fractions due to the enhancement of large chiral factor?rK?0χ. The branching fractions of decays with the vector meson emitted, become much smaller owing to the smaller factor?rK?χ. Moreover, the annihilation type diagram will induce large uncertainties because of the extra free parameter dealing with the endpoint singularity. For the pure annihilation type decays, our predictions are smaller than that from PQCD approach by 2-3 orders of magnitudes. These results will be tested by the ongoing LHCb experiment, forthcoming Belle-II experiment and the proposing circular electron-positron collider. |

Improved Estimates of The $B_(s)\to V V$ Decays in Perturbative QCD Approach

Zhi-Tian Zou; Ahmed Ali; Cai-Dian L╱; Xin Liu; Ying LiSubjects: Physics >> Nuclear Physics

We reexamine the branching ratios,?CP-asymmetries, and other observables in a large number of?Bq→VV(q=u,d,s)?decays in the perturbative QCD (PQCD) approach, where?V?denotes a light vector meson?(ρ,K?,ω,?). The essential difference between this work and the earlier similar works is of parametric origin and in the estimates of the power corrections related to the ratio?r2i=m2Vi/m2B(i=2,3)?(mV?and?mB?denote the masses of the vector and?B?meson, respectively). In particular, we use up-to-date distribution amplitudes for the final state mesons and keep the terms proportional to the ratio?r2i?in our calculations. Our updated calculations are in agreement with the experimental data, except for a limited number of decays which we discuss. We emphasize that the penguin annihilation and the hard-scattering emission contributions are essential to understand the polarization anomaly, such as in the?B→?K??and?Bs→???decay modes. We also compare our results with those obtained in the QCD factorization (QCDF) approach and comment on the similarities and differences, which can be used to discriminate between these approaches in future experiments. |

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