B^0(B+s)→γvv decays are useful to determining the decay constants f_B(f_B_s) and B(B_s) meson wavefunction.Using the B meson wave function determined in hadronic B(Bs) decays,we study the uncertainties due tothe typ...B^0(B+s)→γvv decays are useful to determining the decay constants f_B(f_B_s) and B(B_s) meson wavefunction.Using the B meson wave function determined in hadronic B(Bs) decays,we study the uncertainties due tothe types of B meson wave functions.We find that the branching ratios are sensitive to the type of wave functions andinput parameters,but the energy spectrum is independent.The predicted branching ratios are (0.45-1.04) ×10^(-9) and(2.14-3.27) × 10^(-8) for B^0 and B_s decay,respectively.展开更多
By employing the QCD factorization approach for the exclusive B→Vу decays, we study the exclusive decay B→K^＊у in the top-quark two-Higgs-doublet mode/（T2HDM）. Within the considered parameter space, we find the...By employing the QCD factorization approach for the exclusive B→Vу decays, we study the exclusive decay B→K^＊у in the top-quark two-Higgs-doublet mode/（T2HDM）. Within the considered parameter space, we find the following conclusions （a） A hght charged-Higgs boson with a mass about 200 GeV is clearly excluded by the date of B→K^＊у decay, and this lower limit is comparable with that from the inclusive B→X8＊у decay; （b） The theoretical predictions for CP asymmetry of B→K^＊у in the T2HDM is always less than 1% in size; and （c） The isospin symmetry breaking for B→K^＊у decay in the SM and T2HDM considered here is around 6% in size and well consistent with the data and the general expectations.展开更多
In this paper,we calculate the branching ratios for B^+→D_s^+η,B^+→D_s^+η′,B^+→D_s^(*+)η and B^+→D_s^(*+)η′decays by employing the perturbative QCD (pQCD) factorization approach.Under the two kinds of η-η...In this paper,we calculate the branching ratios for B^+→D_s^+η,B^+→D_s^+η′,B^+→D_s^(*+)η and B^+→D_s^(*+)η′decays by employing the perturbative QCD (pQCD) factorization approach.Under the two kinds of η-η′ mixingschemes,the quark-flavor mixing scheme and the singlet-octet mixing scheme,we find that the calculated branchingratios agree well with the currently available experimental upper limits.We also consider the so called 'f_D_s puzzle',byusing two groups of parameters about the D_s^((*)) meson decay constants,that are f_D_s = 241 MeV,f_D_s~* = 272 MeV andf_D_s = 274 MeV,f_D_s~* = 312 MeV,to calculate the branching ratios for the considered decays.We find that the resultschange 30% by using these two different kinds of paramters.展开更多
By employing the perturbative QCD （pQCD） factorization approach, we calculate the full leading and the partial next-to-leading order （NLO） contributions to the seven B →πη（′） and η（′）η（′） decays. For...By employing the perturbative QCD （pQCD） factorization approach, we calculate the full leading and the partial next-to-leading order （NLO） contributions to the seven B →πη（′） and η（′）η（′） decays. For B^＋→ π＋η（′） decays, the pQCD predictions for their decay rates agree very well with the data after the inclusion of the small NLO contributions. For neutral decays, the pQCD predictions are also consistent with the experimental upper limits and can be tested by the LHC experiments. The measured value of dir .Acp^dir（π＋η）= 19±7% can also be accommodated by the pQCD approach.展开更多
In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0（980）π^0, a0^＋ （980）π^-, a0^-（980）π^＋ and B^- → a0^0 （980）π^-, a0^- （980）π^0 by employin...In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0（980）π^0, a0^＋ （980）π^-, a0^-（980）π^＋ and B^- → a0^0 （980）π^-, a0^- （980）π^0 by employing the perturbative QCD （pQCD） factorization approach at the leading order. We found that （a） the pQCD predictions for the branching ratios are around （0.4-2.8） × 10^-6, consistent with currently available experimental upper limits; （b） the CP asymmetries of B^0→ a0^0（980）π^0 and B^- → a0^- （980）π^0 decays can be large, about （70-80）% for α= 100°.展开更多
We calculate the branching ratios of pure annihilation type decays B0→Ds- K2＊＋ and Bs→Da2 using the perturbative QCD approach based on kT factorization. The branching ratios are predicted to be （60.6-16.5-10.4-2....We calculate the branching ratios of pure annihilation type decays B0→Ds- K2＊＋ and Bs→Da2 using the perturbative QCD approach based on kT factorization. The branching ratios are predicted to be （60.6-16.5-10.4-2.1＋17.3＋4.3＋3.2 ）× 10-6 for B0→Ds- K2＊＋, （1.1-0.4-0.2-0.1＋0.4＋0.1＋0.1）×10-6 for Bs→D0a20 and （2.3-0.8-0.4-0.1＋0.8＋0.2＋0.1）×10-6 for Bs→D-a2＋. They are large enough to be measured in the ongoing experiment. Due to the shortage of contributions from penguin operators, there are no direct CP asymmetries for these decays in the Standard Model. We also derive simple relations among these decay channels to reduce theoretical uncertainties for the experiments ,to test the accuracy of theory, and to search for a signal of new physics.展开更多
Motivated by the large rates of B→(χc0,χc2,hc)K decays observed by the BABAR and Belle collaborations,we investigate the nonfactorizable contributions to these factorization-forbidden decays,which can occur through...Motivated by the large rates of B→(χc0,χc2,hc)K decays observed by the BABAR and Belle collaborations,we investigate the nonfactorizable contributions to these factorization-forbidden decays,which can occur through a gluon exchange between the cc system and the spectator quark.Our numerical results demonstrate that the spectator contributions are capable of producing a large branching ratio consistent with the experiments.As a by-product,we also study the Cabibbo-suppressed decays,such as B→(χc0,χc2,hc)πand the U-spin-related Bs decay,which have so far received less theoretical and experimental attention.The calculated branching ratios reach the order of 10−6,which is within the scope of the Belle-Ⅱ and LHCb experiments.Further,the CP-asymmetry parameters are also calculated for these decays.The obtained results are compared with the available experimental data and numbers from other predictions.We also investigate the sources of theoretical uncertainties in our calculation.展开更多
We consider the effects of the fourth generation quarks on the rare B decay processes described by the b → s（d）vv processes at the quark level. We find that the values of the branching ratios for some of these rare...We consider the effects of the fourth generation quarks on the rare B decay processes described by the b → s（d）vv processes at the quark level. We find that the values of the branching ratios for some of these rare decay processes are much larger than the standard model （SM） predictions. These processes can be used to constrain the relevant free parameters.展开更多
Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e ＋ e ￣ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the r...Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e ＋ e ￣ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the rare decays B → K （＊） l ＋ l￣ in two di-lepton mass bins above and below the J/ψ resonance.For the B → K＊ l ＋ l￣ decay,we also measure the K＊ longitudinal polarization fraction and the di-lepton forwardbackward asymmetry.展开更多
基金Supported by National Science Foundation of Hebei Province of China under Grant No.A2008000421the Natural Science Foundation of Zhejiang Province of China under Grant No.Y606252the Scientific Research Fund of Zhejiang Provincial Education Department of China under Grant No.20051357
文摘B^0(B+s)→γvv decays are useful to determining the decay constants f_B(f_B_s) and B(B_s) meson wavefunction.Using the B meson wave function determined in hadronic B(Bs) decays,we study the uncertainties due tothe types of B meson wave functions.We find that the branching ratios are sensitive to the type of wave functions andinput parameters,but the energy spectrum is independent.The predicted branching ratios are (0.45-1.04) ×10^(-9) and(2.14-3.27) × 10^(-8) for B^0 and B_s decay,respectively.
基金The project partially supported by National Natural Science Foundation of China under Grant Nos. 10275035 and 10575052 and the Specialized Research Fund for Doctoral Program of Higher Education （SRFDP） under Grant No. 20050319008.We are very grateful to GU0 Li-Bo for helpful discussions.
文摘By employing the QCD factorization approach for the exclusive B→Vу decays, we study the exclusive decay B→K^＊у in the top-quark two-Higgs-doublet mode/（T2HDM）. Within the considered parameter space, we find the following conclusions （a） A hght charged-Higgs boson with a mass about 200 GeV is clearly excluded by the date of B→K^＊у decay, and this lower limit is comparable with that from the inclusive B→X8＊у decay; （b） The theoretical predictions for CP asymmetry of B→K^＊у in the T2HDM is always less than 1% in size; and （c） The isospin symmetry breaking for B→K^＊у decay in the SM and T2HDM considered here is around 6% in size and well consistent with the data and the general expectations.
文摘In this paper,we calculate the branching ratios for B^+→D_s^+η,B^+→D_s^+η′,B^+→D_s^(*+)η and B^+→D_s^(*+)η′decays by employing the perturbative QCD (pQCD) factorization approach.Under the two kinds of η-η′ mixingschemes,the quark-flavor mixing scheme and the singlet-octet mixing scheme,we find that the calculated branchingratios agree well with the currently available experimental upper limits.We also consider the so called 'f_D_s puzzle',byusing two groups of parameters about the D_s^((*)) meson decay constants,that are f_D_s = 241 MeV,f_D_s~* = 272 MeV andf_D_s = 274 MeV,f_D_s~* = 312 MeV,to calculate the branching ratios for the considered decays.We find that the resultschange 30% by using these two different kinds of paramters.
基金Supported by National Natural Science Foundation of China (10575052, 10735080)Specialized Research Fund for Doctoral Program of Higher Education (SRFDP) (20050319008)
文摘By employing the perturbative QCD （pQCD） factorization approach, we calculate the full leading and the partial next-to-leading order （NLO） contributions to the seven B →πη（′） and η（′）η（′） decays. For B^＋→ π＋η（′） decays, the pQCD predictions for their decay rates agree very well with the data after the inclusion of the small NLO contributions. For neutral decays, the pQCD predictions are also consistent with the experimental upper limits and can be tested by the LHC experiments. The measured value of dir .Acp^dir（π＋η）= 19±7% can also be accommodated by the pQCD approach.
基金Supported by National Natural Science Foundation of China (10575052,10735080)
文摘In this paper, we calculate the branching ratios and the direct CP-violating asymmetries for decays B^0 → a0^0（980）π^0, a0^＋ （980）π^-, a0^-（980）π^＋ and B^- → a0^0 （980）π^-, a0^- （980）π^0 by employing the perturbative QCD （pQCD） factorization approach at the leading order. We found that （a） the pQCD predictions for the branching ratios are around （0.4-2.8） × 10^-6, consistent with currently available experimental upper limits; （b） the CP asymmetries of B^0→ a0^0（980）π^0 and B^- → a0^- （980）π^0 decays can be large, about （70-80）% for α= 100°.
基金Supported by National Natural Science Foundation of China （11075168）
文摘We calculate the branching ratios of pure annihilation type decays B0→Ds- K2＊＋ and Bs→Da2 using the perturbative QCD approach based on kT factorization. The branching ratios are predicted to be （60.6-16.5-10.4-2.1＋17.3＋4.3＋3.2 ）× 10-6 for B0→Ds- K2＊＋, （1.1-0.4-0.2-0.1＋0.4＋0.1＋0.1）×10-6 for Bs→D0a20 and （2.3-0.8-0.4-0.1＋0.8＋0.2＋0.1）×10-6 for Bs→D-a2＋. They are large enough to be measured in the ongoing experiment. Due to the shortage of contributions from penguin operators, there are no direct CP asymmetries for these decays in the Standard Model. We also derive simple relations among these decay channels to reduce theoretical uncertainties for the experiments ,to test the accuracy of theory, and to search for a signal of new physics.
基金Supported in part by the National Natural Science Foundation of China(11605060,11547020)the Natural Science Foundation of Hebei Province(A2019209449)Department of Education of Hebei Province(BJ2016041)。
文摘Motivated by the large rates of B→(χc0,χc2,hc)K decays observed by the BABAR and Belle collaborations,we investigate the nonfactorizable contributions to these factorization-forbidden decays,which can occur through a gluon exchange between the cc system and the spectator quark.Our numerical results demonstrate that the spectator contributions are capable of producing a large branching ratio consistent with the experiments.As a by-product,we also study the Cabibbo-suppressed decays,such as B→(χc0,χc2,hc)πand the U-spin-related Bs decay,which have so far received less theoretical and experimental attention.The calculated branching ratios reach the order of 10−6,which is within the scope of the Belle-Ⅱ and LHCb experiments.Further,the CP-asymmetry parameters are also calculated for these decays.The obtained results are compared with the available experimental data and numbers from other predictions.We also investigate the sources of theoretical uncertainties in our calculation.
基金Supported in part by the National Natural Science Foundation of China under Grant No. 10975067the Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) under Grant No. 200801650002
文摘We consider the effects of the fourth generation quarks on the rare B decay processes described by the b → s（d）vv processes at the quark level. We find that the values of the branching ratios for some of these rare decay processes are much larger than the standard model （SM） predictions. These processes can be used to constrain the relevant free parameters.
文摘Based on a data sample of 384 million BB pairs collected with the BABAR detector at the PEP-Ⅱ asymmetric e ＋ e ￣ storage ring,we measure branching fractions,direct CP,isospin and lepton-flavor asymmetries for the rare decays B → K （＊） l ＋ l￣ in two di-lepton mass bins above and below the J/ψ resonance.For the B → K＊ l ＋ l￣ decay,we also measure the K＊ longitudinal polarization fraction and the di-lepton forwardbackward asymmetry.
