The branching ratios and CP violations of the B →Dπ decays, including both the color-allowed and the color-suppressed modes, are investigated in detail within QCD framework by considering all diagrams that lead to t...The branching ratios and CP violations of the B →Dπ decays, including both the color-allowed and the color-suppressed modes, are investigated in detail within QCD framework by considering all diagrams that lead to three effective currents of two quarks. An intrinsic mass scale as a dynamical gluon mass is introduced to treat the infrared divergence caused by the soft collinear approximation in the endpoint regions, and the Cutkosky rule is adopted to deal with a physical-region singularity of the on mass-shell quark propagators. When the dynamical gluon mass μg is regarded as a universal sca/e, it is extracted to be around μg = 440 MeV from one of the well-measured B →Dπ decay modes. The resulting predictions for all branching ratios are in agreement with the current experimental measurements. As these decays have no penguin contributions, there are no direct CP asymmetries. Due to interference between the Cabibbo-suppressed and the Cabibbo-favored amplitudes, mixing-induced CP violations are predicted in the B →D^±π^±↓ decays to be consistent with the experimental data at 1-σ level. More precise measurements will be helpful to extracting weak angle 2β＋γ.展开更多
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
There are different approaches for the hadronic B decay calculations,recently.In this paper,we upgrade three of them,namely factorization,QCD factorization and the perturbative QCD approach based on kT factorization,u...There are different approaches for the hadronic B decay calculations,recently.In this paper,we upgrade three of them,namely factorization,QCD factorization and the perturbative QCD approach based on kT factorization,using new parameters and full wave functions.Although they get similar results for many of the branching ratios,the direct CP asymmetries predicted by them are different,which can be tested by recent experimental measurements of B factories.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
We study the unexpectedly large rate for the factorization-forbidden decay B →xcoK within the QCD factorization approach. We use a non-zero gluon mass to regularize the infrared divergences in vertex corrections. The...We study the unexpectedly large rate for the factorization-forbidden decay B →xcoK within the QCD factorization approach. We use a non-zero gluon mass to regularize the infrared divergences in vertex corrections. The end-point singularities arising from spectator corrections are regularized and carefully estimated by the off-shellness of quarks. We find that the contributions arising from the vertex and leading-twist spectator corrections are numerically small, and the twist-3 spectator contribution with chiral enhancement and linear end-point singularity becomes dominant. With reasonable choices for the parameters, the branching ratio for B → XcoK decay is estimated to be in the range （2 ～ 4）× 10^-4, which is compatible with the Belle and BaBar data.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
In this paper, we study the upper bounds on the mass insertion parameters （δAB^q）ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l＋l...In this paper, we study the upper bounds on the mass insertion parameters （δAB^q）ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l＋l- decay can help us to improve the upper bounds on the mass insertions parameters （δAB^u,d）3j,i3 Some regions allowed by the data of Br（B→ X8γ） are excluded by the requirement of an SM-like C7γ （rnb） imposedby the data of Br（B→ X8γ, X8l＋l- ）.展开更多
Ultrafast anisotropic decay is a prominent parameter revealing ultrafast energy and electron transfer; however, it is dimcult to be determined reliably owing to the requirement of a simultaneous availability of the pa...Ultrafast anisotropic decay is a prominent parameter revealing ultrafast energy and electron transfer; however, it is dimcult to be determined reliably owing to the requirement of a simultaneous availability of the parallel and perpendieular polarized decay kinetics. Nowadays, any measurement of anisotropic decay is a kind of approach to the exact simultaneity. Here we report a novel method for a synchronous ultrafast anisotropy decay measurement, which can well determine the anisotropy, even at a very early time, as the rising phase of the excitation laser pulse. The anisotropic decay of the B850 in bacteriM light harvesting antenna complex LH2 of rhodobacter sphaeroides in solution at room temperature with coherent excitation is detected by this method, which shows a polarization response time of 30 fs, and the energy transfer from the initial excitation to the bacteriochlorophylls in B850 ring takes about 7Ors. The anisotropic decay that is probed at the red side of the absorption spectrum, such as 880 nm, has an initial value of 0.4, corresponding to simulated emission, while the blue side with an anisotropy of 0.1 contributes to the ground-state bleaching. Our results show that the coherent excitation covering the whole ring might not be realized owing to the symmetry breaking of LH2： from C9 symmetry in membrane to C2 symmetry in solution.展开更多
The direct CP asymmetry in quasi-two-body decays of B→(V→π^(+)π^(-))P is investigated using the perturbative QCD(PQCD)method,where P represents a pseudoscalar meson,and V refers toρ,ω,andΦmesons.We present the ...The direct CP asymmetry in quasi-two-body decays of B→(V→π^(+)π^(-))P is investigated using the perturbative QCD(PQCD)method,where P represents a pseudoscalar meson,and V refers toρ,ω,andΦmesons.We present the amplitude of the quasi-two-body decay process and investigate the effects of mixed resonances involvingρ^(0)-ω,ρ^(0)-Φ,andω-Φwhile considering the impact of isospin symmetry breaking.We observe significant CP asymmetry when the invariant mass of theπ^(+)π^(-)pair is within the resonance ranges ofρ,ω,andΦmesons.Consequently,we quantify the regional CP asymmetry in these resonance regions.A significant difference is observed when comparing the results obtained with and without the interference of the three vector mesons and isospin conservation.The CP asymmetry results obtained from the three-body decay process,without interference owing to isospin conservation by the PQCD method,are in agreement with the newly updated data acquired by the LHCb experiment.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
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
We present the novel V→K^(+)K^(-)(V=ϕ,ρ,ω)resonance,which generates a strong phase associated with vector meson resonances,leading to significant CP asymmetry in the interference region.Theϕ→K^(+)K^(-),ρ→K^(+)K^...We present the novel V→K^(+)K^(-)(V=ϕ,ρ,ω)resonance,which generates a strong phase associated with vector meson resonances,leading to significant CP asymmetry in the interference region.Theϕ→K^(+)K^(-),ρ→K^(+)K^(-),andω→K^(+)K^(-)resonances arise from the mixing of the vector mesonsϕ,ρ,andω.We calculate the CP asymmetry from the decay mode of B→KKπ(K).Meanwhile,the localized CP asymmetries are presented and a detailed analysis is performed.The CP asymmetry from the decay mode of B−→ϕπ^(-)→K^(+)K^(-)π^(-)is also presented in our framework,which is highly consisted with that of the LHC experiment.The introduced CP asymmetry can provide a favorable theoretical support for experimental exploration in the future.展开更多
By assuming that the scalar meson K＊0 （1430） belongs to the first excited states or the lowest lying ground states of qq＇, we study the pure annihilation-type decays B→K＊0±（1430）K（＊）（-/＋） in the QCD...By assuming that the scalar meson K＊0 （1430） belongs to the first excited states or the lowest lying ground states of qq＇, 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 of the order of 10-8-10-7, which is possible to measure 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＇≈600 GeV（ζ0.02）,both the branching fractions and CP asymmetries of -0B→K＊0±（1430）K-could be changed remarkably, which provides us with a place for probing the effect of new physics. These results could be used to constrain the parameters of the Zj model.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
We investigate CP violation in the decay process B_(s)→ϕ(ρ,ω)P→K^(+)K^(-)P by considering the interference effects ofϕ→K^(+)K^(-),ρ→K^(+)K^(-),andω→K^(+)K^(-)within the framework of the perturbative QCD metho...We investigate CP violation in the decay process B_(s)→ϕ(ρ,ω)P→K^(+)K^(-)P by considering the interference effects ofϕ→K^(+)K^(-),ρ→K^(+)K^(-),andω→K^(+)K^(-)within the framework of the perturbative QCD method(P refers toπ,K,η,andη′pseudoscalar mesons).We analyze the mixings ofϕ−ρ^(0),ϕ−ω,andω−ρ0 and provide the amplitudes of the quasi-two-body decay processes.The CP violation for the B_(s)→K^(+)K^(-)P decay process is obvious in the ranges of the three vector meson interferences.Meanwhile,the localized CP violation can be found to compare with the experimental results from the three-body decay process at the LHC in the near future.展开更多
Based on the assumption of a two-quark structure of the scalar meson f0（980） ,we calculate the branching ratios and CP-violating asymmetries for the four B → f0（980） π and B → f0（980） η^（＇） decays by empl...Based on the assumption of a two-quark structure of the scalar meson f0（980） ,we calculate the branching ratios and CP-violating asymmetries for the four B → f0（980） π and B → f0（980） η^（＇） decays by employing the perturbative QCD（pQCD） factorization approach. The leading order pQCD predictions for branching ratios are,Br（B^-→ f0（980） π^-） ～ 2.5×10^-6,Br（Bˉ^0 → f0（980） π^0） ～ 2.6×10^-7,Br（Bˉ^0 → f0（980） η） ～ 2.5×10^-7 and Br（Bˉ^0 → f0（980） η ） ～ 6.7×10^-7,which are consistent with both the QCD factorization predictions and the experimental upper limits.展开更多
The physical state of ρ−ω−φ mesons can be mixed using the unitary matrix.The decay processes ω→π^(+)π^(−)and φ→π^(+)π^(−)originate from isospin symmetry breaking.The ρ−ω,ρ−φ,and ω−φ interferences lead...The physical state of ρ−ω−φ mesons can be mixed using the unitary matrix.The decay processes ω→π^(+)π^(−)and φ→π^(+)π^(−)originate from isospin symmetry breaking.The ρ−ω,ρ−φ,and ω−φ interferences lead to a resonance contribution to produce strong phases.CP violation is considered from isospin symmetry breaking due to the new strong phase of the first order.CP violation can be enhanced greatly for the decay process B^(0)→π^(+)π^(−)η^((′))when the invariant masses of π^(+)π^(−) pairs are in the area around the ω resonance range and φ resonance range in perturbative QCD.We also discuss the possibility of searching for the predicted CP violation at the LHC.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
We calculate the branching ratio of B → J/ψπ0 with a mixed formalism that combines the QCDimproved factorization and the perturbative QCD approaches.The result is consistent with experimental data.The quite small p...We calculate the branching ratio of B → J/ψπ0 with a mixed formalism that combines the QCDimproved factorization and the perturbative QCD approaches.The result is consistent with experimental data.The quite small penguin contribution in B → J/ψπ0 decay can be calculated with this method.We suggest two methods to extract the weak phase β.One is through the dependence of the mixing induced CP asymmetry SJ/ψπ0 on the weak phase β,the other is from the relation of the total asymmetry ACP with the weak phase β.Our results show that the deviation ΔSJ/ψπ0 of the mixing induced CP asymmetry from sin（-2β） is of O（10-3） and has much less uncertainty.The above O（10-3） deviation can provide a good reference for identifying new physics.展开更多
基金supported by National Natural Science Foundation of China (NSFC) under Grant Nos.10475105,10491306,and 10675039the Knowledge Innovation Program (PKIP) of the Chinese Academy of Sciences
文摘The branching ratios and CP violations of the B →Dπ decays, including both the color-allowed and the color-suppressed modes, are investigated in detail within QCD framework by considering all diagrams that lead to three effective currents of two quarks. An intrinsic mass scale as a dynamical gluon mass is introduced to treat the infrared divergence caused by the soft collinear approximation in the endpoint regions, and the Cutkosky rule is adopted to deal with a physical-region singularity of the on mass-shell quark propagators. When the dynamical gluon mass μg is regarded as a universal sca/e, it is extracted to be around μg = 440 MeV from one of the well-measured B →Dπ decay modes. The resulting predictions for all branching ratios are in agreement with the current experimental measurements. As these decays have no penguin contributions, there are no direct CP asymmetries. Due to interference between the Cabibbo-suppressed and the Cabibbo-favored amplitudes, mixing-induced CP violations are predicted in the B →D^±π^±↓ decays to be consistent with the experimental data at 1-σ level. More precise measurements will be helpful to extracting weak angle 2β＋γ.
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This work was suported by the National Natural Science Foundation of China(Grant Nos.90103013,10475085,10135060).
文摘There are different approaches for the hadronic B decay calculations,recently.In this paper,we upgrade three of them,namely factorization,QCD factorization and the perturbative QCD approach based on kT factorization,using new parameters and full wave functions.Although they get similar results for many of the branching ratios,the direct CP asymmetries predicted by them are different,which can be tested by recent experimental measurements of B factories.
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.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10421503, 10675003 and the Key Grant Project of Ministry of Education under Grant No. 305001
文摘We study the unexpectedly large rate for the factorization-forbidden decay B →xcoK within the QCD factorization approach. We use a non-zero gluon mass to regularize the infrared divergences in vertex corrections. The end-point singularities arising from spectator corrections are regularized and carefully estimated by the off-shellness of quarks. We find that the contributions arising from the vertex and leading-twist spectator corrections are numerically small, and the twist-3 spectator contribution with chiral enhancement and linear end-point singularity becomes dominant. With reasonable choices for the parameters, the branching ratio for B → XcoK decay is estimated to be in the range （2 ～ 4）× 10^-4, which is compatible with the Belle and BaBar data.
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The project partly supported by National Natural Science Foundation of China under Grant Nos. 10275035 and 10575052 and the Research Foundation of Nanjing Normal University under Grant No. 214080A916 .
文摘In this paper, we study the upper bounds on the mass insertion parameters （δAB^q）ij in the minimal super symmetric standard model. We found that the information from the measured branching ratio of B→ X8γ, X8l＋l- decay can help us to improve the upper bounds on the mass insertions parameters （δAB^u,d）3j,i3 Some regions allowed by the data of Br（B→ X8γ） are excluded by the requirement of an SM-like C7γ （rnb） imposedby the data of Br（B→ X8γ, X8l＋l- ）.
基金Supported by the National Natural Science Foundation of China under Grant Nos 20925313,21227003,and 11004236the National Basic Research Program of China under Grant No 2009CB930700the Innovation Program of Chinese Academy of Sciences under Grant No KJCX2-YW-W25
文摘Ultrafast anisotropic decay is a prominent parameter revealing ultrafast energy and electron transfer; however, it is dimcult to be determined reliably owing to the requirement of a simultaneous availability of the parallel and perpendieular polarized decay kinetics. Nowadays, any measurement of anisotropic decay is a kind of approach to the exact simultaneity. Here we report a novel method for a synchronous ultrafast anisotropy decay measurement, which can well determine the anisotropy, even at a very early time, as the rising phase of the excitation laser pulse. The anisotropic decay of the B850 in bacteriM light harvesting antenna complex LH2 of rhodobacter sphaeroides in solution at room temperature with coherent excitation is detected by this method, which shows a polarization response time of 30 fs, and the energy transfer from the initial excitation to the bacteriochlorophylls in B850 ring takes about 7Ors. The anisotropic decay that is probed at the red side of the absorption spectrum, such as 880 nm, has an initial value of 0.4, corresponding to simulated emission, while the blue side with an anisotropy of 0.1 contributes to the ground-state bleaching. Our results show that the coherent excitation covering the whole ring might not be realized owing to the symmetry breaking of LH2： from C9 symmetry in membrane to C2 symmetry in solution.
基金Supported by the Natural Science Foundation of Henan Province,China(252300420319)the National Natural Science Foundation of China(12275024)。
文摘The direct CP asymmetry in quasi-two-body decays of B→(V→π^(+)π^(-))P is investigated using the perturbative QCD(PQCD)method,where P represents a pseudoscalar meson,and V refers toρ,ω,andΦmesons.We present the amplitude of the quasi-two-body decay process and investigate the effects of mixed resonances involvingρ^(0)-ω,ρ^(0)-Φ,andω-Φwhile considering the impact of isospin symmetry breaking.We observe significant CP asymmetry when the invariant mass of theπ^(+)π^(-)pair is within the resonance ranges ofρ,ω,andΦmesons.Consequently,we quantify the regional CP asymmetry in these resonance regions.A significant difference is observed when comparing the results obtained with and without the interference of the three vector mesons and isospin conservation.The CP asymmetry results obtained from the three-body decay process,without interference owing to isospin conservation by the PQCD method,are in agreement with the newly updated data acquired by the LHCb experiment.
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.
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.
基金Supported by the Natural Science Foundation of Henan Province,China(232300420115)the National Natural Science Foundation of China(12275024).
文摘We present the novel V→K^(+)K^(-)(V=ϕ,ρ,ω)resonance,which generates a strong phase associated with vector meson resonances,leading to significant CP asymmetry in the interference region.Theϕ→K^(+)K^(-),ρ→K^(+)K^(-),andω→K^(+)K^(-)resonances arise from the mixing of the vector mesonsϕ,ρ,andω.We calculate the CP asymmetry from the decay mode of B→KKπ(K).Meanwhile,the localized CP asymmetries are presented and a detailed analysis is performed.The CP asymmetry from the decay mode of B−→ϕπ^(-)→K^(+)K^(-)π^(-)is also presented in our framework,which is highly consisted with that of the LHC experiment.The introduced CP asymmetry can provide a favorable theoretical support for experimental exploration in the future.
基金Supported by National Natural Science Foundation of China(11175151,11575151,11375208,11235005)the Program for New Century Excellent Talents in University(NCET)by Ministry of Education of P.R.China(NCET-13-0991)
文摘By assuming that the scalar meson K＊0 （1430） belongs to the first excited states or the lowest lying ground states of qq＇, 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 of the order of 10-8-10-7, which is possible to measure 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＇≈600 GeV（ζ0.02）,both the branching fractions and CP asymmetries of -0B→K＊0±（1430）K-could be changed remarkably, which provides us with a place for probing the effect of new physics. These results could be used to constrain the parameters of the Zj model.
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 by the Natural Science Foundation of Henan Province,China(232300420115).
文摘We investigate CP violation in the decay process B_(s)→ϕ(ρ,ω)P→K^(+)K^(-)P by considering the interference effects ofϕ→K^(+)K^(-),ρ→K^(+)K^(-),andω→K^(+)K^(-)within the framework of the perturbative QCD method(P refers toπ,K,η,andη′pseudoscalar mesons).We analyze the mixings ofϕ−ρ^(0),ϕ−ω,andω−ρ0 and provide the amplitudes of the quasi-two-body decay processes.The CP violation for the B_(s)→K^(+)K^(-)P decay process is obvious in the ranges of the three vector meson interferences.Meanwhile,the localized CP violation can be found to compare with the experimental results from the three-body decay process at the LHC in the near future.
文摘Based on the assumption of a two-quark structure of the scalar meson f0（980） ,we calculate the branching ratios and CP-violating asymmetries for the four B → f0（980） π and B → f0（980） η^（＇） decays by employing the perturbative QCD（pQCD） factorization approach. The leading order pQCD predictions for branching ratios are,Br（B^-→ f0（980） π^-） ～ 2.5×10^-6,Br（Bˉ^0 → f0（980） π^0） ～ 2.6×10^-7,Br（Bˉ^0 → f0（980） η） ～ 2.5×10^-7 and Br（Bˉ^0 → f0（980） η ） ～ 6.7×10^-7,which are consistent with both the QCD factorization predictions and the experimental upper limits.
基金Supported by National Natural Science Foundation of China(11605041)。
文摘The physical state of ρ−ω−φ mesons can be mixed using the unitary matrix.The decay processes ω→π^(+)π^(−)and φ→π^(+)π^(−)originate from isospin symmetry breaking.The ρ−ω,ρ−φ,and ω−φ interferences lead to a resonance contribution to produce strong phases.CP violation is considered from isospin symmetry breaking due to the new strong phase of the first order.CP violation can be enhanced greatly for the decay process B^(0)→π^(+)π^(−)η^((′))when the invariant masses of π^(+)π^(−) pairs are in the area around the ω resonance range and φ resonance range in perturbative QCD.We also discuss the possibility of searching for the predicted CP violation at the LHC.
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.
文摘We calculate the branching ratio of B → J/ψπ0 with a mixed formalism that combines the QCDimproved factorization and the perturbative QCD approaches.The result is consistent with experimental data.The quite small penguin contribution in B → J/ψπ0 decay can be calculated with this method.We suggest two methods to extract the weak phase β.One is through the dependence of the mixing induced CP asymmetry SJ/ψπ0 on the weak phase β,the other is from the relation of the total asymmetry ACP with the weak phase β.Our results show that the deviation ΔSJ/ψπ0 of the mixing induced CP asymmetry from sin（-2β） is of O（10-3） and has much less uncertainty.The above O（10-3） deviation can provide a good reference for identifying new physics.
