We study the Bc,u,d→X(3872)P decays in the perturbative QCD(PQCD)approach,involving the puzzling resonance X(3872),where P represents a light pseudoscalar meson(K orπ).Assuming X(3872)to be a 1++charmonium state,we ...We study the Bc,u,d→X(3872)P decays in the perturbative QCD(PQCD)approach,involving the puzzling resonance X(3872),where P represents a light pseudoscalar meson(K orπ).Assuming X(3872)to be a 1++charmonium state,we obtain the following results.(a)The branching ratios of the Bc+→X(3872)π+and Bc+→X(3872)K+decays are consistent with the results predicted by the covariant light-front approach within errors;however,they are larger than those given by the generalized factorization approach.(b)The branching ratio of the B+→X(3872)K+decay is predicted as(3.8-1.0+1.1)×10-4,which is smaller than the previous PQCD calculation result but still slightly larger than the upper limits set by Belle and BaBar.Hence,we suggest that the B0,+→X(3872)K0,+decays should be precisely measured by the LHCb and Belle II experiments to help probe the inner structure of X(3872).(c)Compared with the Bu,d→X(3872)K decays,the Bu,d→X(3872)πdecays have significantly smaller branching ratios,which drop to values as low as 10-6.(d)The direct CP violations of these considered decays are small(10-3~10-2)because the penguin contributions are loop suppressed compared to the tree contributions.The mixing-induced CP violation of the B→X(3872)K0S decay is highly consistent with the current world average value sin 2β=(69.9±1.7)%.Experimentally testing the results for the branching ratios and CP violations,including the implicit SU(3)and isospin symmetries of these decays,helps probe the nature of X(3872).展开更多
Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K...Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K.We compare our predicted branching ratios for the B_(()(s))→K_(χc0)→Kπ^(+)π-(K^(+)K^(-))decay with available experiment data as well as predictions by other theoretical studies.The branching ratios of these decays are consistent with data and other theoretical predictions.However,in the Cabibbo-suppressed decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=K^(0),π,the values of the branching ratios are of the order of 10^(-7)and 10^(-8).The ratio R_((χ)_(c0))between the decays B^(+)→π^(+)χ_(c0)→π^(+)π^(+)π^(-)and B^(+)→K^(+)χc0→K^(+)π^(+)π^(-)and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.展开更多
Using all experimentally measured charmless B → PP, PV decay modes, where P(V) denotes a light pseudoscalar(vector) meson, we extract the CKM angle γ by a global fit. All hadronic parameters are determined from the ...Using all experimentally measured charmless B → PP, PV decay modes, where P(V) denotes a light pseudoscalar(vector) meson, we extract the CKM angle γ by a global fit. All hadronic parameters are determined from the experimental data, such that the approach is least model dependent. The contributions of the various decay modes are classified by the topological weak Feynman diagram amplitudes, which are determined by the global fit.To improve the precision of the approach, we consider the flavor SU(3) breaking effects of the topological diagram amplitudes of the decay modes by including the form factors and decay constants. The fit result for the CKM angle γ is( 69.8 ± 2.1 ± 0.9)°. It is consistent with the current world average values but has a smaller uncertainty.展开更多
We report some applications of QCD light cone sum rules(LCSR)to B meson weak decays.Special emphasis is on estimates of the form factors for B decays into a pseudoscalar(P)/vector(V)meson,with a certain chiral current...We report some applications of QCD light cone sum rules(LCSR)to B meson weak decays.Special emphasis is on estimates of the form factors for B decays into a pseudoscalar(P)/vector(V)meson,with a certain chiral current correlator.The main new ingredient,as compared with the case of the standard correlators,is that in the operator product expansion calculations,the contributions due to the twist-3 distribution amplitudes of the related light mesons,which are less known and would bring a larger uncertainty to the calculations with the standard correlators,cancel out fully in the B!P case and do out partially in the B!V one.An important observation,which is similar to that in soft collinear effective theory,is made in twist-3 approximation:whereas only one independent form factor is needed for parameterizing the hadronic matrix elements for a B!P transition induced by all the relevant heavy-light quark currents,there exist two independent form factors under the condition of neglecting the terms suppressed by a factor of m2V,for the B!V transition.Therefore,the improved LCSR approach could be of stronger predictive power for the weak form factors.Also,this approach is employed to understand the B!D transitions by introducing a leading twist-2 DA for an energetic D meson,combined with some of other QCDbased approaches.A detailed QCD next-to-leading order calculation of the B!p form factors is presented for an illustrative purpose,and the sum rule results are used to extract the Cabibbo–Kobayashi–Maskawa matrix element jVubj from the latest BaBar data.展开更多
By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^...By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^0（ω, φ）η（＇）, induced by the vertex QCD corrections, the quark-loops as well as the chromo-magnetic penguins. From the numerical results and phenomenological analysis we find that （a） for B^± → ρ^±η（＇） （B^0 → ρ^0（ω, φ）η（＇）decays, the partial NLO contributions to branching ratios are small （large） in magnitude; and （b） the pQCD predictions for ACP^dir（B^± → ρ^±η（＇）） are consistent with the data, while the predicted .ACP（B^0 → ρ^0（ω）η（＇）） are generally large in magnitude and could be tested by the forthcoming LHCb experiments.展开更多
We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scala...We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scalar a_(0)(980)and a_(0)(1450)[K^(∗)_(0)(800)(orκ)and K^(∗)_(0)(1430)],with the perturbative QCD factorization approach under the assumption of two-quark structure for the a_(0)and K^(∗)_(0)states.The numerical results show that the branching ratios of the B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0)decays are in the order of 10^(−6),while the decay rates of the B^(s)_(0)→a^(+)_(0)a^(−)_(0)modes are in the order of 10−5.In light of the measured modes with the same quark components in the pseudoscalar sector,namely,B^(0)_(d)→K^(+)k_(-)and B^(0)_(s)→π^(+)π_(−),the predictions for the considered decay modes in this work are expected to be measured at the Large Hadron Collider beauty and/or Belle-Ⅱexperiments in the(near)future.Meanwhile,it is of great interest to find that the twist-3 distribution amplitudesφ^(S)andφ^(T)with inclusion of the Gegenbauer polynomials for the scalar a_(0)(1450)and K^(∗)_(0)(1430)states in scenario 2 contribute slightly to the branching ratios while significantly to the CP violations in the B^(0)_(d)→K^(∗)_(0)(1430)+K^(∗)_(0)(1430)−and B^(0)_(s)→a_(0)(1450)+a_(0)(1450)−decays,which indicates that,compared to the asymptoticφ^(S)andφ^(T),these Gegenbauer polynomials could change the strong phases evidently in these pure annihilation decay channels.These predictions await for the future confirmation experimentally,which could further provide useful information to help explore the inner structure of the scalars and shed light on the annihilation decay mechanism.展开更多
The rare decays Bs^0（B^-0 s）→D^±π^-＋ can occur only via annihilation-type diagrams in the standard model. In this paper, we calculate branching ratios of these decays in perturbative QCD approach ignoring so...The rare decays Bs^0（B^-0 s）→D^±π^-＋ can occur only via annihilation-type diagrams in the standard model. In this paper, we calculate branching ratios of these decays in perturbative QCD approach ignoring soft final state interaction. From our calculation, we find that their branching ratios are at O（10^-6） with large CP asymmetry, which may be measured in LHC-b experiment in the future.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
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
基金Supported by the National Natural Science Foundation of China(11347030)the Program of Science and Technology Innovation Talents in Universities of Henan Province(14HASTIT037)。
文摘We study the Bc,u,d→X(3872)P decays in the perturbative QCD(PQCD)approach,involving the puzzling resonance X(3872),where P represents a light pseudoscalar meson(K orπ).Assuming X(3872)to be a 1++charmonium state,we obtain the following results.(a)The branching ratios of the Bc+→X(3872)π+and Bc+→X(3872)K+decays are consistent with the results predicted by the covariant light-front approach within errors;however,they are larger than those given by the generalized factorization approach.(b)The branching ratio of the B+→X(3872)K+decay is predicted as(3.8-1.0+1.1)×10-4,which is smaller than the previous PQCD calculation result but still slightly larger than the upper limits set by Belle and BaBar.Hence,we suggest that the B0,+→X(3872)K0,+decays should be precisely measured by the LHCb and Belle II experiments to help probe the inner structure of X(3872).(c)Compared with the Bu,d→X(3872)K decays,the Bu,d→X(3872)πdecays have significantly smaller branching ratios,which drop to values as low as 10-6.(d)The direct CP violations of these considered decays are small(10-3~10-2)because the penguin contributions are loop suppressed compared to the tree contributions.The mixing-induced CP violation of the B→X(3872)K0S decay is highly consistent with the current world average value sin 2β=(69.9±1.7)%.Experimentally testing the results for the branching ratios and CP violations,including the implicit SU(3)and isospin symmetries of these decays,helps probe the nature of X(3872).
基金Supported by the National Natural Science Foundation of China(11235005,11847141,12105112)the Natural Science Foundation of Jiangsu Education Committee(21KJB140027)the Natural Science Foundation of Huaiyin Institute of Technology(21HGZ012)。
文摘Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K.We compare our predicted branching ratios for the B_(()(s))→K_(χc0)→Kπ^(+)π-(K^(+)K^(-))decay with available experiment data as well as predictions by other theoretical studies.The branching ratios of these decays are consistent with data and other theoretical predictions.However,in the Cabibbo-suppressed decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=K^(0),π,the values of the branching ratios are of the order of 10^(-7)and 10^(-8).The ratio R_((χ)_(c0))between the decays B^(+)→π^(+)χ_(c0)→π^(+)π^(+)π^(-)and B^(+)→K^(+)χc0→K^(+)π^(+)π^(-)and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.
基金Supported by National Science Foundation of China(11847040,11947414,11521505,11621131001)Scientific Research Foundation of Inner Mongolia University。
文摘Using all experimentally measured charmless B → PP, PV decay modes, where P(V) denotes a light pseudoscalar(vector) meson, we extract the CKM angle γ by a global fit. All hadronic parameters are determined from the experimental data, such that the approach is least model dependent. The contributions of the various decay modes are classified by the topological weak Feynman diagram amplitudes, which are determined by the global fit.To improve the precision of the approach, we consider the flavor SU(3) breaking effects of the topological diagram amplitudes of the decay modes by including the form factors and decay constants. The fit result for the CKM angle γ is( 69.8 ± 2.1 ± 0.9)°. It is consistent with the current world average values but has a smaller uncertainty.
基金supported by the National Natural Science Foundation of China (11235005)
文摘We report some applications of QCD light cone sum rules(LCSR)to B meson weak decays.Special emphasis is on estimates of the form factors for B decays into a pseudoscalar(P)/vector(V)meson,with a certain chiral current correlator.The main new ingredient,as compared with the case of the standard correlators,is that in the operator product expansion calculations,the contributions due to the twist-3 distribution amplitudes of the related light mesons,which are less known and would bring a larger uncertainty to the calculations with the standard correlators,cancel out fully in the B!P case and do out partially in the B!V one.An important observation,which is similar to that in soft collinear effective theory,is made in twist-3 approximation:whereas only one independent form factor is needed for parameterizing the hadronic matrix elements for a B!P transition induced by all the relevant heavy-light quark currents,there exist two independent form factors under the condition of neglecting the terms suppressed by a factor of m2V,for the B!V transition.Therefore,the improved LCSR approach could be of stronger predictive power for the weak form factors.Also,this approach is employed to understand the B!D transitions by introducing a leading twist-2 DA for an energetic D meson,combined with some of other QCDbased approaches.A detailed QCD next-to-leading order calculation of the B!p form factors is presented for an illustrative purpose,and the sum rule results are used to extract the Cabibbo–Kobayashi–Maskawa matrix element jVubj from the latest BaBar data.
基金Supported by the National Natural Science Foundation of China under Grant No.10575052,10605012,and 10735080
文摘By employing the perturbative QCD （pQCD） factorization approach, we calculate some important next- to-leading-order （NLO） contributions to the two-body charmless hadronic decays B^＋ →ρ^＋η（＇） and B^0 → ρ^0（ω, φ）η（＇）, induced by the vertex QCD corrections, the quark-loops as well as the chromo-magnetic penguins. From the numerical results and phenomenological analysis we find that （a） for B^± → ρ^±η（＇） （B^0 → ρ^0（ω, φ）η（＇）decays, the partial NLO contributions to branching ratios are small （large） in magnitude; and （b） the pQCD predictions for ACP^dir（B^± → ρ^±η（＇）） are consistent with the data, while the predicted .ACP（B^0 → ρ^0（ω）η（＇）） are generally large in magnitude and could be tested by the forthcoming LHCb experiments.
基金supported in part by the National Natural Science Foundation of China under Grant Nos.11765012 and 11205072by the Research Fund of Jiangsu Normal University(No.HB2016004)supported by the Undergraduate Research&Practice Innovation Program of Jiangsu Province(No.201810320103Z)。
文摘We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scalar a_(0)(980)and a_(0)(1450)[K^(∗)_(0)(800)(orκ)and K^(∗)_(0)(1430)],with the perturbative QCD factorization approach under the assumption of two-quark structure for the a_(0)and K^(∗)_(0)states.The numerical results show that the branching ratios of the B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0)decays are in the order of 10^(−6),while the decay rates of the B^(s)_(0)→a^(+)_(0)a^(−)_(0)modes are in the order of 10−5.In light of the measured modes with the same quark components in the pseudoscalar sector,namely,B^(0)_(d)→K^(+)k_(-)and B^(0)_(s)→π^(+)π_(−),the predictions for the considered decay modes in this work are expected to be measured at the Large Hadron Collider beauty and/or Belle-Ⅱexperiments in the(near)future.Meanwhile,it is of great interest to find that the twist-3 distribution amplitudesφ^(S)andφ^(T)with inclusion of the Gegenbauer polynomials for the scalar a_(0)(1450)and K^(∗)_(0)(1430)states in scenario 2 contribute slightly to the branching ratios while significantly to the CP violations in the B^(0)_(d)→K^(∗)_(0)(1430)+K^(∗)_(0)(1430)−and B^(0)_(s)→a_(0)(1450)+a_(0)(1450)−decays,which indicates that,compared to the asymptoticφ^(S)andφ^(T),these Gegenbauer polynomials could change the strong phases evidently in these pure annihilation decay channels.These predictions await for the future confirmation experimentally,which could further provide useful information to help explore the inner structure of the scalars and shed light on the annihilation decay mechanism.
基金The project partly supported by National Natural Science Foundation of China
文摘The rare decays Bs^0（B^-0 s）→D^±π^-＋ can occur only via annihilation-type diagrams in the standard model. In this paper, we calculate branching ratios of these decays in perturbative QCD approach ignoring soft final state interaction. From our calculation, we find that their branching ratios are at O（10^-6） with large CP asymmetry, which may be measured in LHC-b experiment in the future.
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.
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.
