There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B fac...There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity.展开更多
Observation of unexpectedly large global spin alignment of φ vector mesons in non-central heavy-ion collisions by STAR experiment may reveal the non-perturbative nature of quark interaction in hot matter through fluc...Observation of unexpectedly large global spin alignment of φ vector mesons in non-central heavy-ion collisions by STAR experiment may reveal the non-perturbative nature of quark interaction in hot matter through fluctuating strong force field with short correlation length.展开更多
This work shows a didactic model representative of the quarks described in the Standard Model (SM). In the model, particles are represented by structures corresponding to geometric shapes of coupled quantum oscillator...This work shows a didactic model representative of the quarks described in the Standard Model (SM). In the model, particles are represented by structures corresponding to geometric shapes of coupled quantum oscillators (GMP). From these didactic hypotheses emerges an in-depth phenomenology of particles (quarks) fully compatible with that of SM, showing, besides, that the number of possible quarks is six.展开更多
We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e＋e collider. We measure the branching fraction of radiative decay J/ψ→ηcγ, ηc widt...We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e＋e collider. We measure the branching fraction of radiative decay J/ψ→ηcγ, ηc width and mass. Our preliminary results are： M（ηc） = 2979.4± 1.5 ± 1.9 MeV/c^2, Г（ηc） = 27.8±5.1 ±3.3 MeV, B（Jψ→ηcγ） = （2.34±0.15±0.40）%.展开更多
Motivated by our previous study[Phys.Rev.D 104(1),016021(2021)]on the pionic leading-twist distribution amplitude(DA),we revisit theρ-me son leading-twist longitudinal DAφ_(2;ρ)^(‖)(x,μ)in this study.A model prop...Motivated by our previous study[Phys.Rev.D 104(1),016021(2021)]on the pionic leading-twist distribution amplitude(DA),we revisit theρ-me son leading-twist longitudinal DAφ_(2;ρ)^(‖)(x,μ)in this study.A model proposed by Chang based on the DYyson-Schwinger equations is adopted to describe the behavior ofφ_(2;ρ)^(‖)(x,μ).However,theξ-moments ofφ_(2;ρ)^(‖)(x,μ)are calculated with the QCD sum rules in the framework of the background field theory.The sum rule formulas for these moments are improved.More accurate values for the first five nonzeroξ-moments at the typical scaleμ=(1.0,1.4,2.0,3.0)GeV are given,e.g.,atμ=1 GeV,(ξ^(2))>_(2;ρ)^(‖)=0.220(6),(ξ^(4))>_(2;ρ)^(‖)=0.103(4),(ξ^(6))>_(2;ρ)^(‖)=0.066(5),(ξ^(8))>_(2;ρ)^(‖)=0.046(4),and(ξ^(10))>_(2;ρ)^(‖)=0.035(3).By fitting these values with the least squares method,the DSE model forφ_(2;ρ)(x,μ)is determined.By taking the left-handed current light-cone sum rule approach,we obtain the transition form factor in the large recoil region,i.e.,A_(1)(0)=0.498_(-0.012)^(+0.014),A_(2)(0)=0.460_(-0.047)^(+0.055),and V(0)=0.800_(-0.014)^(+0.015),and the ratio r_(2)=0.923_(-0.119)^(+0.133),rV=1.607_(-0.071)^(+0.071).After extrapolating with a rapidly converging series based on z(t)-expansion,we present the|V_(cd)|-independent decay width for the semileptonic decays D→ρ^(l+)v_(l).Finally,the branching fractions are B(D^(0)→ρ^(-)e+v_(e))=1.825_(-0.162)^(+0.170)±0.004,B(D^(+)→ρ^(0)e+v_(e))=2.299_(-0.204)^(+0.214)±0.011,B(D^(0)→ρ^(-)μ^(+)v_(μ))=1.816_(-0.160)^(+0.168)±0.004,and B(D^(+)→ρ^(0)μ+v_(μ))=2.288_(-0.201)^(+0.212)±0.011.展开更多
Within the extended vector meson dominance model,we investigate the𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) reaction and the electromagnetic form factors of the charmed baryon𝛬 Λ_(c)^(+)𝑐.The model par...Within the extended vector meson dominance model,we investigate the𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) reaction and the electromagnetic form factors of the charmed baryon𝛬 Λ_(c)^(+)𝑐.The model parameters are determined by fitting them to the cross sections of the process𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) and the magnetic form factor|G_(M)|of Λ_(c)^(+) .By considering four charmonium-like states,called𝜓(4500),𝜓(4660),𝜓(4790),and𝜓(4900),we can well describe the current data on the𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) reaction from the reaction threshold up to 4.96 GeV.In addition to the total cross sections and|𝐺M|,the ratio|G_(E)/G_(M)|and the effective form factor|Geff|for Λ_(c)^(+) 𝑐are also calculated,and found that these calculations are consistent with the experimental data.Within the fitted model parameters,we have also estimated the charge radius of the charmed Λ_(c)^(+) baryon.展开更多
We briefly review the hadronization pictures adopted in the LUND String Fragmentation Model (LSFM),Webber Cluster Fragmentation Model (WCFM) and Quark Combination Model (QCM),respectively.Predictions of hadron multipl...We briefly review the hadronization pictures adopted in the LUND String Fragmentation Model (LSFM),Webber Cluster Fragmentation Model (WCFM) and Quark Combination Model (QCM),respectively.Predictions of hadron multiplicity,baryon to meson ratios and baryon-antibaryon flavor correlations,especially those related to heavy hadrons at a Z 0 factory obtained by LSFM and QCM,are reported.展开更多
Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framewo...Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.展开更多
In this study,the strong coupling constants of vertices BBΥ,BB^(∗)Υ,B^(∗)B^(∗)Υ,BB^(∗)ηb,and B^(∗)B^(∗)ηb are analyzed in the framework of QCD sum rules.All possible off-shell cases and the contributions of vacuu...In this study,the strong coupling constants of vertices BBΥ,BB^(∗)Υ,B^(∗)B^(∗)Υ,BB^(∗)ηb,and B^(∗)B^(∗)ηb are analyzed in the framework of QCD sum rules.All possible off-shell cases and the contributions of vacuum condensate terms including<qq>,<(qgsσGq>,<g_(s)^(2)G^(2)>,<f^(3)G^(3)>,and<qq><g_(s)^(2)G^(2)>are considered.The momentum dependent strong coupling constants are first calculated and then fitted into the analytical function g(Q^(2)),which is extrapolated to time-like regions to obtain the final values of strong coupling constants.The final results are gBBΥ=40.67+7.55−4.20,gBB^(∗)Υ=11.58+2.19−1.09 GeV−1,gB^(∗)B^(∗)Υ=57.02+5.32−5.31,gBB^(∗)ηb=23.39+4.74−2.30,and gB^(∗)B^(∗)ηb=12.49+2.12−1.35 GeV−1.These strong coupling constants are important input parameters that reflect the dynamic properties of the interactions among the mesons and quarkonia.展开更多
Recently,the experimental measurements of the branching ratios and different polarization asymmetries for processes occurring through flavor-changing-charged current(b→cτν¯_(τ))transitions by BABAR,Belle,and ...Recently,the experimental measurements of the branching ratios and different polarization asymmetries for processes occurring through flavor-changing-charged current(b→cτν¯_(τ))transitions by BABAR,Belle,and LHCb have revealed some significant differences from the corresponding Standard Model(SM)predictions.This has triggered an interest to search for physics beyond the SM in the context of various new physics(NP)models and using the model-independent weak effective Hamiltonian(WEH).Assuming left-handed neutrinos,we add the dimension-six vector,(pseudo-)scalar,and tensor operators with complex Wilson coefficients(WCs)to the SM WEH.Using 60%,30%,and 10%constraints resulting from the branching ratio of B_(c)→τν¯_(τ),we reassess the parametric space of these new physics WCs accommodating the current anomalies based on the most recent HFLAV data of R_(τ/μ,e)(D)and R_(τ/μ,e)(D^(*))and Belle data of F_(L)(D^(*))and P_(τ)(D^(*)).We find that the allowed parametric region of left-handed scalar couplings strongly depends on the constraints of the B_(c)→τν¯_(τ)branching ratio,and the maximum pull from the SM predictions results from the<60%branching ratio limit.Also,the parametric region changes significantly if we extend the analysis by adding LHCb data of R_(τ/μ)(J/ψ)and R_(τ/ℓ)(Λ_(c)).Furthermore,due to the large uncertainties in the measurements of R_(τ/μ)(J/ψ)and R_(τ/ℓ)(X_(c)),we derive the sum rules which complement them with R_(τ/μ,e)(D)and R_(τ/μ,e)(D^(*)).Using the best-fit points of the new complex WCs along with the latest measurements of R_(τ/μ,e)(D(^(*))),we predict the numerical values of the observable R_(τ/ℓ)(Λ_(c)),R_(τ/μ)(J/ψ),and R_(τ/ℓ)(X_(c))from the sum rules.The simultaneous dependence of abovementioned physical observables on the NP WCs is established by plotting their correlation with R_(D) and R_(D^(*)),which are useful to discriminate between various NP scenarios.We find that the most significant impact of NP results from the WC C^(S)_(L)=4C^(T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
Highlighting a golden triangular form in <em>u</em> and <em>d </em>quarks (Quark Geometric Model), we build the geometric structures of light meson <em>η</em> and individualize its...Highlighting a golden triangular form in <em>u</em> and <em>d </em>quarks (Quark Geometric Model), we build the geometric structures of light meson <em>η</em> and individualize its decays and spin. By the structure equations describing mesons, we determine a mathematic procedure to calculate the theoretical value of the mass of light mesons <em>η</em>.展开更多
The Beijing Spectrometer(BESⅢ)experiment,which has been studying particle collisions produced by the Beijing Electron Positron Collider(BEPCⅡ)since 2009,has so far discovered a total of 26 new particle candidates(Fi...The Beijing Spectrometer(BESⅢ)experiment,which has been studying particle collisions produced by the Beijing Electron Positron Collider(BEPCⅡ)since 2009,has so far discovered a total of 26 new particle candidates(Fig.1).The particles,all strongly-interacting hadrons,are thought to be composed of quarks(q),antiquarks(q),and gluons(g)bound together by the strong force in a surprising variety of configurations.Elucidating their properties provides new insight into the complex nature of nuclear interactions and has been one of the central goals of the BESIII Collaboration,which consists of an international team of more than 600 scientists.While several of the newly discovered hadrons are consistent with the conventional two-quark picture of mesons(qq)or the three-quark picture of baryons(qqq),and were expected,others are more surprising and have exotic configurations,such as tetraquarks(qqqq),meson molecules(qq()qq()),glueballs(gg),or hybrid mesons(qgq).They have led to new advances in our theoretical understanding of the strong force,for example through the development of new approaches in quantum field theory[1]or understanding the importance of hadron molecules[2],and have initiated intense experimental effort[3].In the following,we briefly tour the 26 new hadrons,roughly from the heaviest to the lightest.Their names appear in boldface the first time they are mentioned.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
This paper discusses the masses and possible members of 2^1S0 and 2^3S1 meson multiplets in the framework of meson-meson mixing and Regge phenomenology. For the 2^1S0 meson nonet, K＊ （1460） may be the observed stat...This paper discusses the masses and possible members of 2^1S0 and 2^3S1 meson multiplets in the framework of meson-meson mixing and Regge phenomenology. For the 2^1S0 meson nonet, K＊ （1460） may be the observed state of the 2^1S0 isodoublet with a mass of 1400 MeV and the mass of w（1420） is 1412 MeV. For the 2^3S1 meson nonet, K＊（1410） seems too light to be the 2^3S1 ns member. The fact that the agreement between the present findings and those given by experiments and other different approaches is satisfactory implies that the assignments in this paper may be reasonable.展开更多
The exclusive η and π^(0)electroproduction is studied in the handbag approach based on the generalized parton distributions(GPDs)factorization.Predictions of π^(0)and η mesons are calculated for future electron-io...The exclusive η and π^(0)electroproduction is studied in the handbag approach based on the generalized parton distributions(GPDs)factorization.Predictions of π^(0)and η mesons are calculated for future electron-ion collider in China(EicC)energy ranges,using obtained cross sections we extract information on the transversity GPDs contributions to these processes.展开更多
We report results of experiments performed with the KEDR detector at the VEPP-4M e^＋e^- collider. They include precise measurement of the D^0 and D^± meson masses, determination of the ψ（3770） resonance param...We report results of experiments performed with the KEDR detector at the VEPP-4M e^＋e^- collider. They include precise measurement of the D^0 and D^± meson masses, determination of the ψ（3770） resonance parameters, and a search for narrow resonances in e^＋e^- annihilation at center-of-mass energies between 1.85 and 3.1 GeV.展开更多
Heavy meson decays provide an important platform for studies of both QCD and electroweak dynamics,which may contain some portals to understanding of nonperturbative QCD and physics beyond the Standard Model.The factor...Heavy meson decays provide an important platform for studies of both QCD and electroweak dynamics,which may contain some portals to understanding of nonperturbative QCD and physics beyond the Standard Model.The factorization-assisted topological-amplitude approach was proposed to study two-body non-leptonic D meson decays,where a promising QCD inspired approach from first principles is still missing.It was also applied to B meson decays whose subleading power contributions are difficult to calculate.By factorizing topological amplitudes into short distance Wilson coefficients and long distance hadronic matrix elements either to be calculated or to be parameterized,it provides an effective framework to extract information of nonperturbative dynamics involved.With important flavor SU(3)breaking effects taken into account,the data of the decay branching ratios(and also CP asymmetries in B decays)can be fitted well.The extracted amplitudes were further applied to make predictions for other observables,such as CP asymmetries in D decays,mixing parameters in the system.By this review,we will describe the formulation of the factorization-assisted topological-amplitude approach and summarize its applications in D and B meson decays and highlight some of its achievements.展开更多
We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass.Because the proposed super-tau-charm factory will reach a significa...We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass.Because the proposed super-tau-charm factory will reach a significantly enhanced luminosity and BESIII is collecting newψ(3770)→DD data,our results will help improve the measurement precision of future partial wave analyses of charmed meson semi-muonic decays.展开更多
基金Supported in part by National Key Basic Research Program of China (2015CB856700)National Natural Science Foundation of China (NSFC) (11335008,11425524, 11625523, 11635010, 11735014, 11822506, 11935018)+18 种基金the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics (CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257, U1532258, U1732263)CAS Key Research Program of Frontier Science (QYZDJ-SSW-SLH003, QYZDJ-SSW-SLH040)100 Talents Program of CASCAS PIFIthe Thousand Talents Program of ChinaIN-PAC and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG under Contracts NosCollaborative Research Center CRC 1044, FOR 2359Istituto Nazionale di Fisica Nucleare, ItalyKoninklijke Nederlandse Akademie van Wetenschappen (KNAW) (530-4CDP03)Ministry of Development of Turkey (DPT2006K-120470)National Science and Technology fundThe Knut and Alice Wallenberg Foundation (Sweden) (2016.0157)The Swedish Research CouncilU. S. Department of Energy (DE-FG02-05ER41374, DESC-0010118, DE-SC-0012069)University of Groningen (Ru G) and the Helmholtzzentrum fuer Schwerionenforschung Gmb H (GSI), Darmstadtthe Russian Ministry of Science and Higher Education (14.W03.31.0026).
文摘There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESⅢ and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESⅢ, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESⅢ during the remaining operation period of BEPCⅡ. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCⅡ to higher luminosity.
文摘Observation of unexpectedly large global spin alignment of φ vector mesons in non-central heavy-ion collisions by STAR experiment may reveal the non-perturbative nature of quark interaction in hot matter through fluctuating strong force field with short correlation length.
文摘This work shows a didactic model representative of the quarks described in the Standard Model (SM). In the model, particles are represented by structures corresponding to geometric shapes of coupled quantum oscillators (GMP). From these didactic hypotheses emerges an in-depth phenomenology of particles (quarks) fully compatible with that of SM, showing, besides, that the number of possible quarks is six.
基金Supported by the Russian Foundation for Basic Research,grants 08-02-00258,08-02-00258RF Presidential Grant for Sc. Sch. NSh-5655.2008.2
文摘We present a study of the inclusive photon spectra from 5.9 million J/ψ decays collected with the KEDR detector at the VEPP-4M e＋e collider. We measure the branching fraction of radiative decay J/ψ→ηcγ, ηc width and mass. Our preliminary results are： M（ηc） = 2979.4± 1.5 ± 1.9 MeV/c^2, Г（ηc） = 27.8±5.1 ±3.3 MeV, B（Jψ→ηcγ） = （2.34±0.15±0.40）%.
基金Supported in part by the National Natural Science Foundation of China(12265009,12265010,12147102)the Project of Guizhou Provincial Department of Science and Technology(ZK[2021]024,ZK[2023]142)+1 种基金the Project of Guizhou Provincial Department of Education(KY[2021]030)the Chongqing Graduate Research and Innovation Foundation(ydstd1912)。
文摘Motivated by our previous study[Phys.Rev.D 104(1),016021(2021)]on the pionic leading-twist distribution amplitude(DA),we revisit theρ-me son leading-twist longitudinal DAφ_(2;ρ)^(‖)(x,μ)in this study.A model proposed by Chang based on the DYyson-Schwinger equations is adopted to describe the behavior ofφ_(2;ρ)^(‖)(x,μ).However,theξ-moments ofφ_(2;ρ)^(‖)(x,μ)are calculated with the QCD sum rules in the framework of the background field theory.The sum rule formulas for these moments are improved.More accurate values for the first five nonzeroξ-moments at the typical scaleμ=(1.0,1.4,2.0,3.0)GeV are given,e.g.,atμ=1 GeV,(ξ^(2))>_(2;ρ)^(‖)=0.220(6),(ξ^(4))>_(2;ρ)^(‖)=0.103(4),(ξ^(6))>_(2;ρ)^(‖)=0.066(5),(ξ^(8))>_(2;ρ)^(‖)=0.046(4),and(ξ^(10))>_(2;ρ)^(‖)=0.035(3).By fitting these values with the least squares method,the DSE model forφ_(2;ρ)(x,μ)is determined.By taking the left-handed current light-cone sum rule approach,we obtain the transition form factor in the large recoil region,i.e.,A_(1)(0)=0.498_(-0.012)^(+0.014),A_(2)(0)=0.460_(-0.047)^(+0.055),and V(0)=0.800_(-0.014)^(+0.015),and the ratio r_(2)=0.923_(-0.119)^(+0.133),rV=1.607_(-0.071)^(+0.071).After extrapolating with a rapidly converging series based on z(t)-expansion,we present the|V_(cd)|-independent decay width for the semileptonic decays D→ρ^(l+)v_(l).Finally,the branching fractions are B(D^(0)→ρ^(-)e+v_(e))=1.825_(-0.162)^(+0.170)±0.004,B(D^(+)→ρ^(0)e+v_(e))=2.299_(-0.204)^(+0.214)±0.011,B(D^(0)→ρ^(-)μ^(+)v_(μ))=1.816_(-0.160)^(+0.168)±0.004,and B(D^(+)→ρ^(0)μ+v_(μ))=2.288_(-0.201)^(+0.212)±0.011.
基金supported by the National Key R&D Program of China(Grant No.2023YFA1606703)the National Natural Science Foundation of China(Grant No.12075288)the Youth Innovation Promotion Association CAS.
文摘Within the extended vector meson dominance model,we investigate the𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) reaction and the electromagnetic form factors of the charmed baryon𝛬 Λ_(c)^(+)𝑐.The model parameters are determined by fitting them to the cross sections of the process𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) and the magnetic form factor|G_(M)|of Λ_(c)^(+) .By considering four charmonium-like states,called𝜓(4500),𝜓(4660),𝜓(4790),and𝜓(4900),we can well describe the current data on the𝑒e^(+)e^(-)→Λ_(c)+Λ_(c)^(- ) reaction from the reaction threshold up to 4.96 GeV.In addition to the total cross sections and|𝐺M|,the ratio|G_(E)/G_(M)|and the effective form factor|Geff|for Λ_(c)^(+) 𝑐are also calculated,and found that these calculations are consistent with the experimental data.Within the fitted model parameters,we have also estimated the charge radius of the charmed Λ_(c)^(+) baryon.
基金supported in part by the National Natural Science Foundation of China (Grant No.10875073)Natural Science Foundation of Shandong Province (Grant Nos.JQ200902 and ZR2009AM001)Doctoral Science Foundation of University of Jinan (Grant No.B0527)
文摘We briefly review the hadronization pictures adopted in the LUND String Fragmentation Model (LSFM),Webber Cluster Fragmentation Model (WCFM) and Quark Combination Model (QCM),respectively.Predictions of hadron multiplicity,baryon to meson ratios and baryon-antibaryon flavor correlations,especially those related to heavy hadrons at a Z 0 factory obtained by LSFM and QCM,are reported.
基金Supported by Ho Chi Minh City University of Technology and Education(T2022-26)。
文摘Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.
基金Supported by the National Natural Science Foundation of China(12175068)Natural Science Foundation of Hebei Province,China(A2018502124)。
文摘In this study,the strong coupling constants of vertices BBΥ,BB^(∗)Υ,B^(∗)B^(∗)Υ,BB^(∗)ηb,and B^(∗)B^(∗)ηb are analyzed in the framework of QCD sum rules.All possible off-shell cases and the contributions of vacuum condensate terms including<qq>,<(qgsσGq>,<g_(s)^(2)G^(2)>,<f^(3)G^(3)>,and<qq><g_(s)^(2)G^(2)>are considered.The momentum dependent strong coupling constants are first calculated and then fitted into the analytical function g(Q^(2)),which is extrapolated to time-like regions to obtain the final values of strong coupling constants.The final results are gBBΥ=40.67+7.55−4.20,gBB^(∗)Υ=11.58+2.19−1.09 GeV−1,gB^(∗)B^(∗)Υ=57.02+5.32−5.31,gBB^(∗)ηb=23.39+4.74−2.30,and gB^(∗)B^(∗)ηb=12.49+2.12−1.35 GeV−1.These strong coupling constants are important input parameters that reflect the dynamic properties of the interactions among the mesons and quarkonia.
文摘Recently,the experimental measurements of the branching ratios and different polarization asymmetries for processes occurring through flavor-changing-charged current(b→cτν¯_(τ))transitions by BABAR,Belle,and LHCb have revealed some significant differences from the corresponding Standard Model(SM)predictions.This has triggered an interest to search for physics beyond the SM in the context of various new physics(NP)models and using the model-independent weak effective Hamiltonian(WEH).Assuming left-handed neutrinos,we add the dimension-six vector,(pseudo-)scalar,and tensor operators with complex Wilson coefficients(WCs)to the SM WEH.Using 60%,30%,and 10%constraints resulting from the branching ratio of B_(c)→τν¯_(τ),we reassess the parametric space of these new physics WCs accommodating the current anomalies based on the most recent HFLAV data of R_(τ/μ,e)(D)and R_(τ/μ,e)(D^(*))and Belle data of F_(L)(D^(*))and P_(τ)(D^(*)).We find that the allowed parametric region of left-handed scalar couplings strongly depends on the constraints of the B_(c)→τν¯_(τ)branching ratio,and the maximum pull from the SM predictions results from the<60%branching ratio limit.Also,the parametric region changes significantly if we extend the analysis by adding LHCb data of R_(τ/μ)(J/ψ)and R_(τ/ℓ)(Λ_(c)).Furthermore,due to the large uncertainties in the measurements of R_(τ/μ)(J/ψ)and R_(τ/ℓ)(X_(c)),we derive the sum rules which complement them with R_(τ/μ,e)(D)and R_(τ/μ,e)(D^(*)).Using the best-fit points of the new complex WCs along with the latest measurements of R_(τ/μ,e)(D(^(*))),we predict the numerical values of the observable R_(τ/ℓ)(Λ_(c)),R_(τ/μ)(J/ψ),and R_(τ/ℓ)(X_(c))from the sum rules.The simultaneous dependence of abovementioned physical observables on the NP WCs is established by plotting their correlation with R_(D) and R_(D^(*)),which are useful to discriminate between various NP scenarios.We find that the most significant impact of NP results from the WC C^(S)_(L)=4C^(T
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).
文摘Highlighting a golden triangular form in <em>u</em> and <em>d </em>quarks (Quark Geometric Model), we build the geometric structures of light meson <em>η</em> and individualize its decays and spin. By the structure equations describing mesons, we determine a mathematic procedure to calculate the theoretical value of the mass of light mesons <em>η</em>.
文摘The Beijing Spectrometer(BESⅢ)experiment,which has been studying particle collisions produced by the Beijing Electron Positron Collider(BEPCⅡ)since 2009,has so far discovered a total of 26 new particle candidates(Fig.1).The particles,all strongly-interacting hadrons,are thought to be composed of quarks(q),antiquarks(q),and gluons(g)bound together by the strong force in a surprising variety of configurations.Elucidating their properties provides new insight into the complex nature of nuclear interactions and has been one of the central goals of the BESIII Collaboration,which consists of an international team of more than 600 scientists.While several of the newly discovered hadrons are consistent with the conventional two-quark picture of mesons(qq)or the three-quark picture of baryons(qqq),and were expected,others are more surprising and have exotic configurations,such as tetraquarks(qqqq),meson molecules(qq()qq()),glueballs(gg),or hybrid mesons(qgq).They have led to new advances in our theoretical understanding of the strong force,for example through the development of new approaches in quantum field theory[1]or understanding the importance of hadron molecules[2],and have initiated intense experimental effort[3].In the following,we briefly tour the 26 new hadrons,roughly from the heaviest to the lightest.Their names appear in boldface the first time they are mentioned.
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.
文摘This paper discusses the masses and possible members of 2^1S0 and 2^3S1 meson multiplets in the framework of meson-meson mixing and Regge phenomenology. For the 2^1S0 meson nonet, K＊ （1460） may be the observed state of the 2^1S0 isodoublet with a mass of 1400 MeV and the mass of w（1420） is 1412 MeV. For the 2^3S1 meson nonet, K＊（1410） seems too light to be the 2^3S1 ns member. The fact that the agreement between the present findings and those given by experiments and other different approaches is satisfactory implies that the assignments in this paper may be reasonable.
基金supported by is Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB34030301)the CAS president’s international fellowship initiative(Grant No.2021VMA0005)
文摘The exclusive η and π^(0)electroproduction is studied in the handbag approach based on the generalized parton distributions(GPDs)factorization.Predictions of π^(0)and η mesons are calculated for future electron-ion collider in China(EicC)energy ranges,using obtained cross sections we extract information on the transversity GPDs contributions to these processes.
基金Supported by Russian Foundation for Basic Research,Grant 04-02-16712,07-02-00816,07-02-01162RF Presidential Grant for Sc.Sch.NSh-5655.2008.2
文摘We report results of experiments performed with the KEDR detector at the VEPP-4M e^＋e^- collider. They include precise measurement of the D^0 and D^± meson masses, determination of the ψ（3770） resonance parameters, and a search for narrow resonances in e^＋e^- annihilation at center-of-mass energies between 1.85 and 3.1 GeV.
基金supported by the National Natural Science Foundation of China (Grant Nos.12005068,12105148,12105112,and 12105099)the Natural Science Foundation of Jiangsu Education Committee (Grant No.21KJB140027).
文摘Heavy meson decays provide an important platform for studies of both QCD and electroweak dynamics,which may contain some portals to understanding of nonperturbative QCD and physics beyond the Standard Model.The factorization-assisted topological-amplitude approach was proposed to study two-body non-leptonic D meson decays,where a promising QCD inspired approach from first principles is still missing.It was also applied to B meson decays whose subleading power contributions are difficult to calculate.By factorizing topological amplitudes into short distance Wilson coefficients and long distance hadronic matrix elements either to be calculated or to be parameterized,it provides an effective framework to extract information of nonperturbative dynamics involved.With important flavor SU(3)breaking effects taken into account,the data of the decay branching ratios(and also CP asymmetries in B decays)can be fitted well.The extracted amplitudes were further applied to make predictions for other observables,such as CP asymmetries in D decays,mixing parameters in the system.By this review,we will describe the formulation of the factorization-assisted topological-amplitude approach and summarize its applications in D and B meson decays and highlight some of its achievements.
基金supported in part by the Joint Large-Scale Scientific Facility Fund of the National Natural Science Foundation of China(NSFC)(11875054,12192263)the Chinese Academy of Sciences(U2032104)+6 种基金supported in part by the NSFC(11905023,12047564,12147102)the Natural Science Foundation of Chongqing,China(cstc2020jcyj-msxmX0555)the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202200605,KJQN202200621)supported in part by the Natural Science Foundation of Henan,China(222300420554,232300421140)the Project of Youth Backbone Teachers of Colleges and Universities of Henan Province,China(2020GGJS017)the Youth Talent Support Project of Henan Province,China(2021HYTP002)the Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(NLK2021-08)。
文摘We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass.Because the proposed super-tau-charm factory will reach a significantly enhanced luminosity and BESIII is collecting newψ(3770)→DD data,our results will help improve the measurement precision of future partial wave analyses of charmed meson semi-muonic decays.
