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 calculate the D s 1 (2536) ^+ decays into D*K channels,including the decay D s 1 (2536) + → D + π-K + through a virtual D*0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement ...We calculate the D s 1 (2536) ^+ decays into D*K channels,including the decay D s 1 (2536) + → D + π-K + through a virtual D*0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement with the recent Belle and BABAR data,being the results sensitive to 1 P 1 and 3 P 1 mixture.展开更多
In this paper,we investigate the charmed meson rare decay process D^(+)→π^(+)v■using an approach based on QCD sum rules.First,the pion twist-2,3 distribution amplitude(DA)moments<ξ_(2)^(n);|μand<ξ3;π(p,σ...In this paper,we investigate the charmed meson rare decay process D^(+)→π^(+)v■using an approach based on QCD sum rules.First,the pion twist-2,3 distribution amplitude(DA)moments<ξ_(2)^(n);|μand<ξ3;π(p,σ),n>|μ,are calculated up to the tenth and fourth orders,respectively,in the QCD sum rules according to the background field theory.After constructing the light-cone harmonic oscillator model for the pion twist-2,3 D As,we obtain their behaviors by matching the calculatedξ-moments.Then,the D→πtransition form factors(TFFs)are calculated using an approach based on QCD light-cone sum rules.The vector form factor at the large recoil region is f_(+)^(D)→^(π)(0)=0.627_(-0.080)^(+0.120).Using the rapidly converging simplified series expansion of z(q^(2),t),we present the TFFs and corresponding angular coefficients in the whole squared momentum transfer physical region.Based on nonstandard neutrino interactions,the■^(0)→π^(+)e■_(e)decay can be related to the■^(0)→π^(+)e■_(e)decay indirectly.Thus,we first describe the semileptonic decay process■^(0)→π^(+)e■_(e),differential decay widths,and branching fraction with B(■^(0)→π^(+)e■_(e))=0.308_(-0.066)^(+0.155)×10^(2).The■^(0)→π^(+)e■_(e)differential/total predictions for forward-backward asymmetry,q^(2)-differential flat terms,and lepton polarization asymmetry are also reported.The prediction for the D^(+)→π^(+)v■branching fraction isB(D^(+)→π^(+)v■)=1.85_(-0.46)+^(0.93)×10^(-8).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 contributions for the kaon pair from the intermediate statesρ(1450)^(+) andρ(1700)^(+) in the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K+K¯^(0)are analyzed within the ...The contributions for the kaon pair from the intermediate statesρ(1450)^(+) andρ(1700)^(+) in the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K+K¯^(0)are analyzed within the perturbative QCD factorization approach.The decay amplitudes for all concerned decays in this work are dominated by the factorizable Feynman diagrams with the emission of the kaon pair,and the chargedρmesons should be of great importance in the KK channel of the related three-body B decays.Moreover,these quasi-two-body decays are CKM-favored,and the relevant branching ratios are predicted to be in the order of 10^(−5),which have the potential to be measured by experiments.It is also shown that the contributions of the subprocessesρ(1450,1700)^(+)→KK for the three-body B meson decays are considerable according to the total three-body branching fractions presented by Belle.Therefore,the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K^(+)K¯^(0)can be employed to study the properties ofρ(1450)andρ(1700)in the LHCb and Belle-II experiments.展开更多
The recent measurements of RK^(+),R_(K_(S)^(O)),RK^(*+),Bs→μ+μ-,a set of CP-averaged angular observables for the B^(0)→K^(*0)μ^(+)μ^(-)decay and its isospin partner B^(+)→K^(*+)μ^(+)μ^(-)by the LHCb Collabora...The recent measurements of RK^(+),R_(K_(S)^(O)),RK^(*+),Bs→μ+μ-,a set of CP-averaged angular observables for the B^(0)→K^(*0)μ^(+)μ^(-)decay and its isospin partner B^(+)→K^(*+)μ^(+)μ^(-)by the LHCb Collaboration consistently hint at lepton universality violation in the b→sll transitions.In this work,we first perform global fits to the b→sll data and show that five one-dimensional scenarios,i.e,δC_(9)^(μ),δC_(10)^(μ),δC_(L)^(μ),δC_(9)^(μ)=C_(10)^(μ’),andδC_(9)^(μ)=-C_(9)^(μ’)can best explain the so-called B anamolies.Furthermore,we explore how these scenarios can be distinguished from each other.For this purpose,we first study the combinations of four angular asymmetries Ai(i=3,4,5,9)and find that they cannot distinguish the five new physics scenarios.We then show that a newly constructed ratio RS can uniquely discriminate the five new physics scenarios in proper intervals of q^(2) if it can be measured with percent-level precision.展开更多
We study the quasi-two-body decays B(s)ψ[K*(892)K*(1410)K*(1680)]ψKπby employing the perturbative QCD(PQCD)factorization approach,where the charmoniaψrepresents J/ψandψ(2S).The corresponding decay channels are s...We study the quasi-two-body decays B(s)ψ[K*(892)K*(1410)K*(1680)]ψKπby employing the perturbative QCD(PQCD)factorization approach,where the charmoniaψrepresents J/ψandψ(2S).The corresponding decay channels are studied by constructing the kaon-pion distribution amplitude(DA)ΦKπP,which comprises important final state interactions between the kaon and pion in the resonant region.Relativistic Breit-Wigner formulas are adopted to parameterize the time-like form factor FKπappearing in the kaon-pion DAs.The SU(3)flavor symmetry breaking effect resulting from the mass difference between the kaon and pion is taken into account,which makes significant contributions to the longitudinal polarizations.The observed branching ratios and the polarization fractions of B(s)ψK*(892)ψKπare accommodated by tuning hadronic parameters for the kaon-pion DAs.The PQCD predictions for B(s)ψ[K*(1410)K*(1680)]ψKπmodes from the same set of parameters can be tested by precise data obtained in the future from LHCb and BelleⅡexperiments.展开更多
By employing the perturbative QCD (pQCD) factorization approach, we calculate the new physics contributions to the four B→Kη(') decays in the Standard Model (SM) with a fourth generation of fermions (SM4), ...By employing the perturbative QCD (pQCD) factorization approach, we calculate the new physics contributions to the four B→Kη(') decays in the Standard Model (SM) with a fourth generation of fermions (SM4), induced by the loop diagrams involving t' quark. Within the considered parameter space of the SM4 we find that: (a) the next-to-leading order (NLO) pQCD predictions for the branching ratios and CP-violating asymmetries in both the SM and SM4 generally agree with the data within one standard deviation; (b) for Br(B→Kη), the inclusion of the fourth generation contributions can improve the agreement between the theoretical predictions and the data effectively; (c) however, for Br(B→Kη') the decrease due to t' loops is disfavored by the data; and, (d) the new physics corrections to the CP-violating asymmetries of the considered decays are only about 10%.展开更多
We present a preliminary measurement of the B(Ds→μvu) with the Belle experiment at the KEKB collider. We select Ds →μvu decays with a method that provides a high-purity of the selected sample and an absolute mea...We present a preliminary measurement of the B(Ds→μvu) with the Belle experiment at the KEKB collider. We select Ds →μvu decays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction. The results are based on a data sample of 550 fb^-1 and are compared to similar measurements by other experiments as well as to the predictions of LQCD. We conclude with short prospects for improvements in the accuracy of the measurement.展开更多
Over the last few years LHCb found some discrepancies in b → sl^+l^-FCNC transitions, including anomalies in the angular observables of B→K^*μ^+μ^-, particularly in P′5, in the low dimuon mass region. Recently...Over the last few years LHCb found some discrepancies in b → sl^+l^-FCNC transitions, including anomalies in the angular observables of B→K^*μ^+μ^-, particularly in P′5, in the low dimuon mass region. Recently,these anomalies have been confirmed by Belle, CMS and ATLAS. As direct evidence of physics beyond the Standard Model is absent so far, these anomalies are being interpreted as indirect hints of new physics. In this context, we study the implications of the family non-universal Z′ model for the angular observables P(1,2,3), P′(4,5,6) and newly proposed lepton flavor universality violation observables, Q(4,5), in the B → K^*(→Kπ)μ^+μ^-decay channel in the low dimuon mass region. To see the variation in the values of these observables from their Standard Model values, we have chosen different scenarios for the Z′ model. It is found that these angular observables are sensitive to the values of the parameters of the Z′ model. We have also found that with the present parametric space of the Z′ model,the P′5-anomaly could be accommodated. However, more statistics on the anomalies in the angular observables are helpful to reveal the status of the considered model and, in general, the nature of new physics.展开更多
In this paper,we calculated the branching ratios and direct CP violation of the four B→Kπ decays with the inclusion of all currently known next-to-leading order(NLO) contributions by employing the perturbative QCD...In this paper,we calculated the branching ratios and direct CP violation of the four B→Kπ decays with the inclusion of all currently known next-to-leading order(NLO) contributions by employing the perturbative QCD(pQCD) factorization approach.We found that(a) Besides the 10%enhancement from the NLO vertex corrections,the quark-loops and magnetic penguins,the NLO contributions to the form factors can provide an additional^15%enhancement to the branching ratios,and lead to a very good agreement with the data;(b) The NLO pQCD predictions are A_(CP)^(dir)(B^0→K~+π~0)=(-6.5±3.1)%and A_(CP)^(dir)(B~+→K~+π~0)=(2.2±2.0)%,become well consistent with the data due to the inclusion of the NLO contributions.展开更多
Based on a systematic investigation of J/ψ(ψ')→VP, where V and P stand for light vector and pseudoscalar mesons, we identify the role played by the electromagnetic (EM) transitions and intermediate meson loop ...Based on a systematic investigation of J/ψ(ψ')→VP, where V and P stand for light vector and pseudoscalar mesons, we identify the role played by the electromagnetic (EM) transitions and intermediate meson loop transitions, which are essential ingredients for understanding the J/ψ and ψ' couplings to VP. We show that on the one hand, the EM transitions have relatively larger interferences in ψ'→ρπ and K^*^-K +c.c. as explicitly shown by vector meson dominance (VMD). On the other hand, the strong decay of ψ' receives relatively larger destructive interferences from the intermediate meson loop transitions. By identifying these mechanisms in an overall study of J/ψ(ψ') → VP, we provide a coherent understanding of the so-called "ρπ puzzle".展开更多
In this work,we study the localized CP violation and the branching fraction of the four-body decay^ˉB 0→K^−π^+π^−π^+by employing a quasi-two-body QCD factorization approach.Considering the interference of^ˉB 0→...In this work,we study the localized CP violation and the branching fraction of the four-body decay^ˉB 0→K^−π^+π^−π^+by employing a quasi-two-body QCD factorization approach.Considering the interference of^ˉB 0→ˉK^∗0(700)ρ0(770)→K^−π^+π^−π^+and^ˉB 0→ˉK∗(892)f0(500)→K^−π^+π^−π^+channels,we predict ACP(^ˉB 0→K^−π^+π^−π^+)∈[0.15,0.28]and B(^ˉB 0→K^−π^+π^−π^+)∈[1.73,5.10]×10^−7,respectively,which shows that the interference mechanism of these two channels can induce the localized CP violation to this four-body decay.Meanwhile,within the two quark model framework for the scalar mesons f0(500)andˉK^∗0(700),we calculate the direct CP violations and branching fractions of the^ˉB 0→ˉK^∗0(700)ρ0(770)and^ˉB 0→ˉK∗(892)f0(500)decays,respectively.The corresponding results are ACP(^ˉB 0→ˉK^∗0(700)ρ0(770))∈[0.20,0.36],ACP(^ˉB 0→ˉK∗(892)f0(500))∈[0.08,0.12],B(^ˉB 0→ˉK^∗0(700)ρ0(770)∈[6.76,18.93]×10^−8 and B(^ˉB 0→ˉK∗(892)f0(500))∈[2.66,4.80]×10^−6,indicating that the CP violations of these two-body decays are both positive and the branching fractions quite different.These studies provide a new way to investigate the aforementioned four-body decay and can be helpful in clarifying the configuration of the structure of the light scalar meson.展开更多
We calculate theD^0-D^-0 mixing parameter y in the factorization-assisted topological-amplitude(FAT)approach, considering contributions from D^0→PP, PV, and VV modes, where P(V) stands for a pseudoscalar(vector...We calculate theD^0-D^-0 mixing parameter y in the factorization-assisted topological-amplitude(FAT)approach, considering contributions from D^0→PP, PV, and VV modes, where P(V) stands for a pseudoscalar(vector) meson. The D^0→PP and PV decay amplitudes are extracted in the FAT approach, and the D^0→VV decay amplitudes with final states in the longitudinal polarization are estimated via the parameter set for D^0→PV. It is found that the VV contribution to y, being of order of 10-4, is negligible, and that the PP and PV contributions amount only up to y_(PP+PV) =(0.21±0.07)%, a prediction more precise than those previously obtained in the literature,and much lower than the experimental data yexp =(0.61 ±0.08)%. We conclude that D^0 meson decays into other two-body and multi-particle final states are relevant to the evaluation of y, so it is difficult to understand it fully in an exclusive approach.展开更多
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 Ministerio de Ciencia y Tecnología(FPA2007-65748)Junta de Castilla y León(SA-106A07,GR12)+1 种基金European Community-Research Infrastructure Integrating Activity"Study of Strongly Interacting Matter"(HadronPhysics2 Grant no.227431)Spanish Ingenio-Consolider 2010 Program CPAN(CSD2007-00042)
文摘We calculate the D s 1 (2536) ^+ decays into D*K channels,including the decay D s 1 (2536) + → D + π-K + through a virtual D*0 in a constituent quark model.Widths and S/D amplitudes ratio are in agreement with the recent Belle and BABAR data,being the results sensitive to 1 P 1 and 3 P 1 mixture.
基金Supported in part by the National Natural Science Foundation of China(12265010,12265009)the Project of Guizhou Provincial Department of Science and Technology(ZK[2021]024,ZK[2023]142)。
文摘In this paper,we investigate the charmed meson rare decay process D^(+)→π^(+)v■using an approach based on QCD sum rules.First,the pion twist-2,3 distribution amplitude(DA)moments<ξ_(2)^(n);|μand<ξ3;π(p,σ),n>|μ,are calculated up to the tenth and fourth orders,respectively,in the QCD sum rules according to the background field theory.After constructing the light-cone harmonic oscillator model for the pion twist-2,3 D As,we obtain their behaviors by matching the calculatedξ-moments.Then,the D→πtransition form factors(TFFs)are calculated using an approach based on QCD light-cone sum rules.The vector form factor at the large recoil region is f_(+)^(D)→^(π)(0)=0.627_(-0.080)^(+0.120).Using the rapidly converging simplified series expansion of z(q^(2),t),we present the TFFs and corresponding angular coefficients in the whole squared momentum transfer physical region.Based on nonstandard neutrino interactions,the■^(0)→π^(+)e■_(e)decay can be related to the■^(0)→π^(+)e■_(e)decay indirectly.Thus,we first describe the semileptonic decay process■^(0)→π^(+)e■_(e),differential decay widths,and branching fraction with B(■^(0)→π^(+)e■_(e))=0.308_(-0.066)^(+0.155)×10^(2).The■^(0)→π^(+)e■_(e)differential/total predictions for forward-backward asymmetry,q^(2)-differential flat terms,and lepton polarization asymmetry are also reported.The prediction for the D^(+)→π^(+)v■branching fraction isB(D^(+)→π^(+)v■)=1.85_(-0.46)+^(0.93)×10^(-8).
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Supported by the National Natural Science Foundation of China(11947011)the Natural Science Foundation of Jiangsu Province(BK20191010)the Scientific Research Foundation of Nanjing Institute of Technology(YKJ201854)。
文摘The contributions for the kaon pair from the intermediate statesρ(1450)^(+) andρ(1700)^(+) in the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K+K¯^(0)are analyzed within the perturbative QCD factorization approach.The decay amplitudes for all concerned decays in this work are dominated by the factorizable Feynman diagrams with the emission of the kaon pair,and the chargedρmesons should be of great importance in the KK channel of the related three-body B decays.Moreover,these quasi-two-body decays are CKM-favored,and the relevant branching ratios are predicted to be in the order of 10^(−5),which have the potential to be measured by experiments.It is also shown that the contributions of the subprocessesρ(1450,1700)^(+)→KK for the three-body B meson decays are considerable according to the total three-body branching fractions presented by Belle.Therefore,the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K^(+)K¯^(0)can be employed to study the properties ofρ(1450)andρ(1700)in the LHCb and Belle-II experiments.
基金Partly supported by the National Natural Science Foundation of China(11735003,11975041,11961141004)the fundamental Research Funds for the Central Universities+1 种基金supported by the National Natural Science Foundation of China(12147145)Project funded by China Postdoctoral Science Foundation(2021M700343)。
文摘The recent measurements of RK^(+),R_(K_(S)^(O)),RK^(*+),Bs→μ+μ-,a set of CP-averaged angular observables for the B^(0)→K^(*0)μ^(+)μ^(-)decay and its isospin partner B^(+)→K^(*+)μ^(+)μ^(-)by the LHCb Collaboration consistently hint at lepton universality violation in the b→sll transitions.In this work,we first perform global fits to the b→sll data and show that five one-dimensional scenarios,i.e,δC_(9)^(μ),δC_(10)^(μ),δC_(L)^(μ),δC_(9)^(μ)=C_(10)^(μ’),andδC_(9)^(μ)=-C_(9)^(μ’)can best explain the so-called B anamolies.Furthermore,we explore how these scenarios can be distinguished from each other.For this purpose,we first study the combinations of four angular asymmetries Ai(i=3,4,5,9)and find that they cannot distinguish the five new physics scenarios.We then show that a newly constructed ratio RS can uniquely discriminate the five new physics scenarios in proper intervals of q^(2) if it can be measured with percent-level precision.
基金Supported by the National Natural Science Foundation of China(11947013,11605060,11775117,11547020)Supported by the Natural Science Foundation of Jiangsu Province(BK20190508)+1 种基金the Research Start-up Funding of Nanjing Agricultural UniversitySupported in part by the Natural Science Foundation of Hebei Province(A2019209449)。
文摘We study the quasi-two-body decays B(s)ψ[K*(892)K*(1410)K*(1680)]ψKπby employing the perturbative QCD(PQCD)factorization approach,where the charmoniaψrepresents J/ψandψ(2S).The corresponding decay channels are studied by constructing the kaon-pion distribution amplitude(DA)ΦKπP,which comprises important final state interactions between the kaon and pion in the resonant region.Relativistic Breit-Wigner formulas are adopted to parameterize the time-like form factor FKπappearing in the kaon-pion DAs.The SU(3)flavor symmetry breaking effect resulting from the mass difference between the kaon and pion is taken into account,which makes significant contributions to the longitudinal polarizations.The observed branching ratios and the polarization fractions of B(s)ψK*(892)ψKπare accommodated by tuning hadronic parameters for the kaon-pion DAs.The PQCD predictions for B(s)ψ[K*(1410)K*(1680)]ψKπmodes from the same set of parameters can be tested by precise data obtained in the future from LHCb and BelleⅡexperiments.
基金Supported by National Natural Science Foundation of China(11235005)Project on Graduate Students Education and Innovation of Jiangsu Province(CXZZ13 0391)
文摘By employing the perturbative QCD (pQCD) factorization approach, we calculate the new physics contributions to the four B→Kη(') decays in the Standard Model (SM) with a fourth generation of fermions (SM4), induced by the loop diagrams involving t' quark. Within the considered parameter space of the SM4 we find that: (a) the next-to-leading order (NLO) pQCD predictions for the branching ratios and CP-violating asymmetries in both the SM and SM4 generally agree with the data within one standard deviation; (b) for Br(B→Kη), the inclusion of the fourth generation contributions can improve the agreement between the theoretical predictions and the data effectively; (c) however, for Br(B→Kη') the decrease due to t' loops is disfavored by the data; and, (d) the new physics corrections to the CP-violating asymmetries of the considered decays are only about 10%.
文摘We present a preliminary measurement of the B(Ds→μvu) with the Belle experiment at the KEKB collider. We select Ds →μvu decays with a method that provides a high-purity of the selected sample and an absolute measurement of the branching fraction. The results are based on a data sample of 550 fb^-1 and are compared to similar measurements by other experiments as well as to the predictions of LQCD. We conclude with short prospects for improvements in the accuracy of the measurement.
文摘Over the last few years LHCb found some discrepancies in b → sl^+l^-FCNC transitions, including anomalies in the angular observables of B→K^*μ^+μ^-, particularly in P′5, in the low dimuon mass region. Recently,these anomalies have been confirmed by Belle, CMS and ATLAS. As direct evidence of physics beyond the Standard Model is absent so far, these anomalies are being interpreted as indirect hints of new physics. In this context, we study the implications of the family non-universal Z′ model for the angular observables P(1,2,3), P′(4,5,6) and newly proposed lepton flavor universality violation observables, Q(4,5), in the B → K^*(→Kπ)μ^+μ^-decay channel in the low dimuon mass region. To see the variation in the values of these observables from their Standard Model values, we have chosen different scenarios for the Z′ model. It is found that these angular observables are sensitive to the values of the parameters of the Z′ model. We have also found that with the present parametric space of the Z′ model,the P′5-anomaly could be accommodated. However, more statistics on the anomalies in the angular observables are helpful to reveal the status of the considered model and, in general, the nature of new physics.
基金Supported by National Natural Science Foundation of China(10975074,11235005)
文摘In this paper,we calculated the branching ratios and direct CP violation of the four B→Kπ decays with the inclusion of all currently known next-to-leading order(NLO) contributions by employing the perturbative QCD(pQCD) factorization approach.We found that(a) Besides the 10%enhancement from the NLO vertex corrections,the quark-loops and magnetic penguins,the NLO contributions to the form factors can provide an additional^15%enhancement to the branching ratios,and lead to a very good agreement with the data;(b) The NLO pQCD predictions are A_(CP)^(dir)(B^0→K~+π~0)=(-6.5±3.1)%and A_(CP)^(dir)(B~+→K~+π~0)=(2.2±2.0)%,become well consistent with the data due to the inclusion of the NLO contributions.
基金Supported by National Natural Science Foundation of China (10675131,10491306,10547001,90403031)Chinese Academy of Sciences (KJCX3-SYW-N2)UK EPSRC(GR/S99433/01)
文摘Based on a systematic investigation of J/ψ(ψ')→VP, where V and P stand for light vector and pseudoscalar mesons, we identify the role played by the electromagnetic (EM) transitions and intermediate meson loop transitions, which are essential ingredients for understanding the J/ψ and ψ' couplings to VP. We show that on the one hand, the EM transitions have relatively larger interferences in ψ'→ρπ and K^*^-K +c.c. as explicitly shown by vector meson dominance (VMD). On the other hand, the strong decay of ψ' receives relatively larger destructive interferences from the intermediate meson loop transitions. By identifying these mechanisms in an overall study of J/ψ(ψ') → VP, we provide a coherent understanding of the so-called "ρπ puzzle".
基金Supported by National Natural Science Foundation of China(11575023,11775024,11947001,11605150)the Fundamental Research Funds for the Provincial Universities of Zhejiang Province and Ningbo Natural Science Foundation(2019A610067)。
文摘In this work,we study the localized CP violation and the branching fraction of the four-body decay^ˉB 0→K^−π^+π^−π^+by employing a quasi-two-body QCD factorization approach.Considering the interference of^ˉB 0→ˉK^∗0(700)ρ0(770)→K^−π^+π^−π^+and^ˉB 0→ˉK∗(892)f0(500)→K^−π^+π^−π^+channels,we predict ACP(^ˉB 0→K^−π^+π^−π^+)∈[0.15,0.28]and B(^ˉB 0→K^−π^+π^−π^+)∈[1.73,5.10]×10^−7,respectively,which shows that the interference mechanism of these two channels can induce the localized CP violation to this four-body decay.Meanwhile,within the two quark model framework for the scalar mesons f0(500)andˉK^∗0(700),we calculate the direct CP violations and branching fractions of the^ˉB 0→ˉK^∗0(700)ρ0(770)and^ˉB 0→ˉK∗(892)f0(500)decays,respectively.The corresponding results are ACP(^ˉB 0→ˉK^∗0(700)ρ0(770))∈[0.20,0.36],ACP(^ˉB 0→ˉK∗(892)f0(500))∈[0.08,0.12],B(^ˉB 0→ˉK^∗0(700)ρ0(770)∈[6.76,18.93]×10^−8 and B(^ˉB 0→ˉK∗(892)f0(500))∈[2.66,4.80]×10^−6,indicating that the CP violations of these two-body decays are both positive and the branching fractions quite different.These studies provide a new way to investigate the aforementioned four-body decay and can be helpful in clarifying the configuration of the structure of the light scalar meson.
基金Supported by National Natural Science Foundation of China(11347027,11505083,11375208,11521505,1162113100,11235005,U1732101)Ministry of Science and Technology of R.O.C.(MOST-104-2112-M-001-037-MY3)DFG Forschergruppe FOR 1873"Quark Flavour Physics and Effective Field Theories"
文摘We calculate theD^0-D^-0 mixing parameter y in the factorization-assisted topological-amplitude(FAT)approach, considering contributions from D^0→PP, PV, and VV modes, where P(V) stands for a pseudoscalar(vector) meson. The D^0→PP and PV decay amplitudes are extracted in the FAT approach, and the D^0→VV decay amplitudes with final states in the longitudinal polarization are estimated via the parameter set for D^0→PV. It is found that the VV contribution to y, being of order of 10-4, is negligible, and that the PP and PV contributions amount only up to y_(PP+PV) =(0.21±0.07)%, a prediction more precise than those previously obtained in the literature,and much lower than the experimental data yexp =(0.61 ±0.08)%. We conclude that D^0 meson decays into other two-body and multi-particle final states are relevant to the evaluation of y, so it is difficult to understand it fully in an exclusive approach.