We present a concise review of the vector charmonium state ψ(4230), which was originally labelled as Y(4260)in the literature. As one of the earliest candidates for a quantum chromodynamics exotic states, its interpr...We present a concise review of the vector charmonium state ψ(4230), which was originally labelled as Y(4260)in the literature. As one of the earliest candidates for a quantum chromodynamics exotic states, its interpretation has initiated various ideas about possible manifestations of non-perturbative mechanisms in the charmonium mass regime. In this short article we briefly review the experimental status of ψ(4230) and discuss possible theoretical interpretations. We will focus on four broadly investigated scenarios, i.e., tetraquark, hybrid, hadro-quarkonium,and hadronic molecule, and highlight the key issues based on these approaches. Crucial experimental observables,e.g., mass position, lineshapes, di-lepton decay width Γ_(ee), production rates in B meson decays, dominant hadronic decay patterns, and the potential 1^(-+)and 0^(--)exotic partners, are assessed, which can provide crucial structure information for understanding this mysterious state.展开更多
Using the phenomenological relativistic harmonic model （RHM） for quarks, we have obtained the masses of S wave charmonium states. The full Hamiltonian used in the investigation has Lorentz scalar plus vector confine...Using the phenomenological relativistic harmonic model （RHM） for quarks, we have obtained the masses of S wave charmonium states. The full Hamiltonian used in the investigation has Lorentz scalar plus vector confinement potential, along with the confined one gluon exchange potential （COGEP）. A good agreement with the experimental masses for the ground state and the radially excited states is obtained for both the triplet and singlet S wave mesons. The calculated charge radii, meson decay constants, leptonic decay width, two photon decay width, and the radiative M1 decay width are in good agreement with the experimental results.展开更多
We investigate the spectrum and decay rates of charmonium states within the framework of the non relativistic quark model by employing a Coulomb like potential from the perturbative one gluon exchange and the linear c...We investigate the spectrum and decay rates of charmonium states within the framework of the non relativistic quark model by employing a Coulomb like potential from the perturbative one gluon exchange and the linear confining potential along with the potential derived from instanton vacuum to account for the hyperfine mass splitting of charmonium states in variational approach. We predict radiative E1, M1, two-photon, lepton and two-gluon decay rates of low lying charmonium states. An overall agreement is obtained with the experimental masses and decay widths.We have estimated the branching ratio of two gluons decaying into light hadrons.展开更多
We calculate the exclusive charmonium photo-production in the framework of color glass condensate.To obtain a good description of the vector meson production experimental data at HERA,we introduce a vector meson mass ...We calculate the exclusive charmonium photo-production in the framework of color glass condensate.To obtain a good description of the vector meson production experimental data at HERA,we introduce a vector meson mass dependent skewness factor into the skewness effect.Then we extend the skewness improved model to the LHC energies.The numerical results of our model are in good agreement with theΨ/Ψ and Ψ（2S）data in ultraperipheral proton-proton collisions at LHC,which show the significance of the vector meson mass-dependent skewness factor.A prediction of the exclusive charmonium photo-production in ultra-peripheral nucleus-nucleus collisions is performed since it can provide a good way to test the effectiveness of the color glass condensate.展开更多
Asymmetric line shape of states is a distinguished characteristic which is often encountered when thresholds and states interacts. Fifty years ago, Fano[1] that the interaction of bare states with one or several thres...Asymmetric line shape of states is a distinguished characteristic which is often encountered when thresholds and states interacts. Fifty years ago, Fano[1] that the interaction of bare states with one or several thresholds of continua would give rise to special asymmetric peaks of the corresponding resonances, which is a common interference phenomenon in quantum physics. It is more obvious for sharp resonances, e:g:, heavy quarkonium states, because their widths are smaller by orders of magnitudes than their masses. The (3770) state is narrow with a width of around 30 MeV and locates about 35 MeV above the D￣D threshold. It is ideal to investigate how this threshold effect influences the properties of states.展开更多
In this work,we study the charmonium(-like)spectrum below 4.1 GeV using the diabatic approach,which offers a unified description of conventional and unconventional heavy meson states.Compared to previous studies,we co...In this work,we study the charmonium(-like)spectrum below 4.1 GeV using the diabatic approach,which offers a unified description of conventional and unconventional heavy meson states.Compared to previous studies,we consider a more realistic cc potential by including the spin-dependent interactions,which allows us to obtain more states and insights into the charmonium spectrum.Based on our calculation,we obtain the masses of the charmonium spectrum,which align well with experimental data.We also present the probabilities of finding various components,i.e.,cc or meson-meson pairs,in these states.Our results support the arguments that X_(c1)(3872),Ψ(4040),and X_(c2)(3930)have significant molecular components.In addition,our calculations show that X_(c0)(3860)and Ψ(3770)can be considered as candidates for the charmonium states X_(c0)(2P)and Ψ(1D),respectively.展开更多
The construction of BESⅢ detector has been finished and the data taking is under plan. Some physics topics on charmonium decays at BESIII experiment are discussed in this paper. The measurement of properties of ηc a...The construction of BESⅢ detector has been finished and the data taking is under plan. Some physics topics on charmonium decays at BESIII experiment are discussed in this paper. The measurement of properties of ηc and η′c at BESⅢ is discussed and the expected precision of the measurement is estimated based on BOSS. Also the XcJ decay and the measurement of hyperon decay parameters are mentioned.展开更多
Motivated by the large rates of B→(χc0,χc2,hc)K decays observed by the BABAR and Belle collaborations,we investigate the nonfactorizable contributions to these factorization-forbidden decays,which can occur through...Motivated by the large rates of B→(χc0,χc2,hc)K decays observed by the BABAR and Belle collaborations,we investigate the nonfactorizable contributions to these factorization-forbidden decays,which can occur through a gluon exchange between the cc system and the spectator quark.Our numerical results demonstrate that the spectator contributions are capable of producing a large branching ratio consistent with the experiments.As a by-product,we also study the Cabibbo-suppressed decays,such as B→(χc0,χc2,hc)πand the U-spin-related Bs decay,which have so far received less theoretical and experimental attention.The calculated branching ratios reach the order of 10−6,which is within the scope of the Belle-Ⅱ and LHCb experiments.Further,the CP-asymmetry parameters are also calculated for these decays.The obtained results are compared with the available experimental data and numbers from other predictions.We also investigate the sources of theoretical uncertainties in our calculation.展开更多
We propose a novel type of interpolating field operator, which manifests the hybrid-like configuration that the charm quark-antiquark pair recoils against gluonie degrees of freedom. A heavy vector charmonium-like sta...We propose a novel type of interpolating field operator, which manifests the hybrid-like configuration that the charm quark-antiquark pair recoils against gluonie degrees of freedom. A heavy vector charmonium-like state with a mass of 4.33（2） GeV is disentangled from the conventional charmonium states in the quenched approximation. This state has affinity for the hybrid-like operators but couples less to the relevant quark bilinear operator. We also try to extract its leptonic decay constant and give a tentative upper limit that it is less than one tenth of that of J/ψ, which corresponds to a leptonic decay width about dozens of eV. The connection of this state with X（4260） is also discussed.展开更多
Recently, the LHCb experiment announced 3.5σ evidence for direct CP violation in D0 decay by looking at the difference between A CP （D0 → K＋ K- ） and A CP （D0 →π＋ π- ）. This is the first evidence of CP viol...Recently, the LHCb experiment announced 3.5σ evidence for direct CP violation in D0 decay by looking at the difference between A CP （D0 → K＋ K- ） and A CP （D0 →π＋ π- ）. This is the first evidence of CP violation in a charm system, which may indicate new physics beyond the Standard Model. Motivated by this measurement, we review rare processes in charmonium decay, especially, the weak decay, C or P violated decay, and lepton flavor violated decays. In case the new physics appears in charm sector, these rare decays of charmonium states will provide an opportunity to search for significant contributions from physics beyond the Standard Model. With huge J/ψ and ψ（2S） samples in BES experiment, the rare decays may be feasible.展开更多
We report recent results on charmonium spectroscopy and decay from the CLEO-c experiment at the Cornell electrompositron storage ring accelerator, CESR. Most of the results are based on the analysis of 54 pb-1 of lumi...We report recent results on charmonium spectroscopy and decay from the CLEO-c experiment at the Cornell electrompositron storage ring accelerator, CESR. Most of the results are based on the analysis of 54 pb-1 of luminosity collected at the ψ（2S） resonance, corresponding to 27 M ψ（2S） decays. We concentrate on radiative decays of ψ（2S） and J/ψ, on two-body mesonic decay of XcJ, on hadronic decay of the he, and on higher multipoles in the two-photon cascade ψ（2S）→γχcJ, XcJ→γJ/ψ.展开更多
Using ～ 14 × 10^6 ψ（2S） and ～ 58 × 10^ J/ ψ data collected at BES Ⅱ/BEPC, the branching fraction of ψ（2S）→Ω-Ω^＋ is measured with about 5a statistical significance. The A electric dipole and ∧...Using ～ 14 × 10^6 ψ（2S） and ～ 58 × 10^ J/ ψ data collected at BES Ⅱ/BEPC, the branching fraction of ψ（2S）→Ω-Ω^＋ is measured with about 5a statistical significance. The A electric dipole and ∧ decay parameter are studied using the decay J/ψ →∧∧→ ppπ^＋π^-. Using （106±3）× 10^6 ψ（2S） decays collected at BESⅢ/BEPC Ⅱ, we have obtained some interesting physics results. The branching fractions of XcJ→π^0π^0, ηη are measured with precision improved. The mass and width of he（l^1P1） state, together with the branching fractions of Br（ψ（2S） →π^0hc） and Br（hc →γηc） are the first measurements. Surprisingly, the decays of Xc1→φφ, ωω, and ωφ are firstly observed in BESⅢ data.展开更多
The cross sections for e^＋e^- →π^＋ π^-J/ψ, π^＋π^-ψ（2S）, K^＋K^-J/ψ, DD1D^0D1-π^＋ ＋c.c., D^＊D＋c.c., and D^＊D^＊ are measured using data sample collected on or near the T（4S） resonance with the Bell...The cross sections for e^＋e^- →π^＋ π^-J/ψ, π^＋π^-ψ（2S）, K^＋K^-J/ψ, DD1D^0D1-π^＋ ＋c.c., D^＊D＋c.c., and D^＊D^＊ are measured using data sample collected on or near the T（4S） resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y（4260）, is observed in π^＋π^-J/ψ final state. In addition, there is another cluster of events at around 4.05 GeV/c^2. Two resonant structures are observed in the π^＋π^-ψ（2S） invariant mass distribution, one at 4361±9±9 MeV/c^2 with a width of 74±15±10 MeV/c2, and another at 4664 ±11±5 MeV/c2 with a width of 48±15±3 MeV/c^2. The rich structures observed in all these final states indicate that our understanding of the vector charmonium states above the open charm threshold is still poor, let alone the other possible dynamics such as charmonium hybrids or final state re-scattering and so on.展开更多
We present a search for new charmonium like states in e^＋e^- annihilation using the initial-state radiation and the process e^＋e^- →J/ψ D（^＊）D（^＊）. The analyses are based on a huge data sample recorded near ...We present a search for new charmonium like states in e^＋e^- annihilation using the initial-state radiation and the process e^＋e^- →J/ψ D（^＊）D（^＊）. The analyses are based on a huge data sample recorded near the T（4S） resonance with the Belle detector at the KEKB e^＋e^- asymmetric-energy collider.展开更多
The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measu...The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measurements; that is, we succeed in reproducing the enhancement structures of Zb（10610） and Zb（10650）. Inspired by this success, we also predict the corresponding enhancement structures in open charm oue-pion decays of higher charmonia near the thresholds of D＊D- and D＊D-＊.展开更多
The line shapes to observe ηc in charmonium transitions, i.e., ψ（2S）, J/ψ→γηc, are investigated. The ηc line shapes in exclusive decays or by observing the inclusive photon spectrum are given. The sensitiviti...The line shapes to observe ηc in charmonium transitions, i.e., ψ（2S）, J/ψ→γηc, are investigated. The ηc line shapes in exclusive decays or by observing the inclusive photon spectrum are given. The sensitivities to measure the ηc resonance parameters are also evaluated. With more than two thousand ηc events observed, the precision of the ηc decay width measurement will be improved by better than 3%. However, the uncertainties associated with the ηc modified line shapes will dominate the systematic errors and this will prohibit precision mass and width measurements.展开更多
The φ-charmonium dissociation reactions in hadronic matter are studied.Unpolarised cross sections for ФJ/ψ → Ds^-Ds^＋, ФJ/ψ →Ds^＊-Ds^＋ or Ds^-Ds^＊＋, ФJ/ψ →Ds^＊-Ds^＊＋, Фψ′→Ds^＊-Ds^＋, Фψ′→ ...The φ-charmonium dissociation reactions in hadronic matter are studied.Unpolarised cross sections for ФJ/ψ → Ds^-Ds^＋, ФJ/ψ →Ds^＊-Ds^＋ or Ds^-Ds^＊＋, ФJ/ψ →Ds^＊-Ds^＊＋, Фψ′→Ds^＊-Ds^＋, Фψ′→ Ds^＊-Ds^＋ or Ds^-Ds^＊＋,Фψ′→Ds^＊-Ds^＊＋,Фχc →Ds^-Ds^＋, Фχc→Ds^＊-Ds^＋ or Ds^-Ds^＊＋ and Фχc → Ds^＊-Ds^＊＋ are calculated in the Born approximation,in the quark-interchange mechanism and with a temperature-dependent quark potential.The potential leads to remarkable temperature dependence of the cross sections.With the cross sections and the Ф distribution function we calculate the dissociation rates of the charmonia in interactions with the Ф meson in hadronic matter.The dependence of the rates on temperature and charmonium momentum is relevant to the influence of Ф mesons on charmonium suppression.展开更多
We report the progress on understanding some of those existing puzzles in charmonium decays.We show that the intermediate meson loops （IML） as a long-distance transition mechanism will provide novel insights into th...We report the progress on understanding some of those existing puzzles in charmonium decays.We show that the intermediate meson loops （IML） as a long-distance transition mechanism will provide novel insights into these issues.In particular,we show that the IML mechanism would be essentially important for understanding the ψ（3770） non-DD decays.We also comment that such a mechanism is correlated with the Okubo-Zweig-Iizuka （OZI） rule evasions in charmonium hadronic decays.展开更多
This exploratory study computes two-photon decay widths of pseudo-scalar(ηc)and scalar(χc0)charmonium using two ensembles of Nf=2 twisted mass lattice QCD gauge configurations.The simulation is performed using two l...This exploratory study computes two-photon decay widths of pseudo-scalar(ηc)and scalar(χc0)charmonium using two ensembles of Nf=2 twisted mass lattice QCD gauge configurations.The simulation is performed using two lattice ensembles with lattice spacings a=0.067 fm with size 323×64 and a=0.085 fm with size 243×48.The decay widths for the two charmonia are obtained within the expected ballpark,but are however smaller than the experimental ones.Possible reasons for these discrepancies are discussed.展开更多
We propose that the X(3915)observed in the J/w channel is the same state as the Xe2(3930),and the X(3960),observed in the D,D,channel,is an S-wave D,D,hadronic molecule.In addition,the jpC=0^(++)component in the B^(+)...We propose that the X(3915)observed in the J/w channel is the same state as the Xe2(3930),and the X(3960),observed in the D,D,channel,is an S-wave D,D,hadronic molecule.In addition,the jpC=0^(++)component in the B^(+)→D^(+)D K^(+)assigned to the X(3915)in the current Review of Particle Physics has the same origin as the X(3960),which has a mass around 3.94 GeV.To check the proposal,the available data in the DD and D,D,channels from both B decays andγγfusion reaction are analyzed considering both the DD-D,D,-D'D'-D,D,coupled channels with o^(++)and a 2^(++)state introduced additionally.It is found that all the data in different processes can be simultaneously well reproduced,and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73,3.94,3.99 and 4.23 Gev,respectively.The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons.展开更多
基金supported in part by the National Natural Science Foundation of China (Grant Nos.12375073 and 12235018)。
文摘We present a concise review of the vector charmonium state ψ(4230), which was originally labelled as Y(4260)in the literature. As one of the earliest candidates for a quantum chromodynamics exotic states, its interpretation has initiated various ideas about possible manifestations of non-perturbative mechanisms in the charmonium mass regime. In this short article we briefly review the experimental status of ψ(4230) and discuss possible theoretical interpretations. We will focus on four broadly investigated scenarios, i.e., tetraquark, hybrid, hadro-quarkonium,and hadronic molecule, and highlight the key issues based on these approaches. Crucial experimental observables,e.g., mass position, lineshapes, di-lepton decay width Γ_(ee), production rates in B meson decays, dominant hadronic decay patterns, and the potential 1^(-+)and 0^(--)exotic partners, are assessed, which can provide crucial structure information for understanding this mysterious state.
基金the BRNS for funding the project(Sanction No.2010/37P/18/BRNS)
文摘Using the phenomenological relativistic harmonic model （RHM） for quarks, we have obtained the masses of S wave charmonium states. The full Hamiltonian used in the investigation has Lorentz scalar plus vector confinement potential, along with the confined one gluon exchange potential （COGEP）. A good agreement with the experimental masses for the ground state and the radially excited states is obtained for both the triplet and singlet S wave mesons. The calculated charge radii, meson decay constants, leptonic decay width, two photon decay width, and the radiative M1 decay width are in good agreement with the experimental results.
文摘We investigate the spectrum and decay rates of charmonium states within the framework of the non relativistic quark model by employing a Coulomb like potential from the perturbative one gluon exchange and the linear confining potential along with the potential derived from instanton vacuum to account for the hyperfine mass splitting of charmonium states in variational approach. We predict radiative E1, M1, two-photon, lepton and two-gluon decay rates of low lying charmonium states. An overall agreement is obtained with the experimental masses and decay widths.We have estimated the branching ratio of two gluons decaying into light hadrons.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11765005,11305040,IRG11521064,11775097 and 11465021the Fund of Science and Technology Department of Guizhou Province under Grant No[2015]2114the Education Department of Guizhou Province under Grant No.KY[2017]004
文摘We calculate the exclusive charmonium photo-production in the framework of color glass condensate.To obtain a good description of the vector meson production experimental data at HERA,we introduce a vector meson mass dependent skewness factor into the skewness effect.Then we extend the skewness improved model to the LHC energies.The numerical results of our model are in good agreement with theΨ/Ψ and Ψ（2S）data in ultraperipheral proton-proton collisions at LHC,which show the significance of the vector meson mass-dependent skewness factor.A prediction of the exclusive charmonium photo-production in ultra-peripheral nucleus-nucleus collisions is performed since it can provide a good way to test the effectiveness of the color glass condensate.
基金National Natural Science Foundation of China (11405222, 11347146)
文摘Asymmetric line shape of states is a distinguished characteristic which is often encountered when thresholds and states interacts. Fifty years ago, Fano[1] that the interaction of bare states with one or several thresholds of continua would give rise to special asymmetric peaks of the corresponding resonances, which is a common interference phenomenon in quantum physics. It is more obvious for sharp resonances, e:g:, heavy quarkonium states, because their widths are smaller by orders of magnitudes than their masses. The (3770) state is narrow with a width of around 30 MeV and locates about 35 MeV above the D￣D threshold. It is ideal to investigate how this threshold effect influences the properties of states.
基金Supported by the National Natural Science Foundation of China(U1832160)Natural Science Foundation of Shaanxi Province,China(2024JC-YBMS-010)。
文摘In this work,we study the charmonium(-like)spectrum below 4.1 GeV using the diabatic approach,which offers a unified description of conventional and unconventional heavy meson states.Compared to previous studies,we consider a more realistic cc potential by including the spin-dependent interactions,which allows us to obtain more states and insights into the charmonium spectrum.Based on our calculation,we obtain the masses of the charmonium spectrum,which align well with experimental data.We also present the probabilities of finding various components,i.e.,cc or meson-meson pairs,in these states.Our results support the arguments that X_(c1)(3872),Ψ(4040),and X_(c2)(3930)have significant molecular components.In addition,our calculations show that X_(c0)(3860)and Ψ(3770)can be considered as candidates for the charmonium states X_(c0)(2P)and Ψ(1D),respectively.
基金National Natural Science Foundation of China(10491303)100 Talents Program of CAS(U-25)
文摘The construction of BESⅢ detector has been finished and the data taking is under plan. Some physics topics on charmonium decays at BESIII experiment are discussed in this paper. The measurement of properties of ηc and η′c at BESⅢ is discussed and the expected precision of the measurement is estimated based on BOSS. Also the XcJ decay and the measurement of hyperon decay parameters are mentioned.
基金Supported in part by the National Natural Science Foundation of China(11605060,11547020)the Natural Science Foundation of Hebei Province(A2019209449)Department of Education of Hebei Province(BJ2016041)。
文摘Motivated by the large rates of B→(χc0,χc2,hc)K decays observed by the BABAR and Belle collaborations,we investigate the nonfactorizable contributions to these factorization-forbidden decays,which can occur through a gluon exchange between the cc system and the spectator quark.Our numerical results demonstrate that the spectator contributions are capable of producing a large branching ratio consistent with the experiments.As a by-product,we also study the Cabibbo-suppressed decays,such as B→(χc0,χc2,hc)πand the U-spin-related Bs decay,which have so far received less theoretical and experimental attention.The calculated branching ratios reach the order of 10−6,which is within the scope of the Belle-Ⅱ and LHCb experiments.Further,the CP-asymmetry parameters are also calculated for these decays.The obtained results are compared with the available experimental data and numbers from other predictions.We also investigate the sources of theoretical uncertainties in our calculation.
基金part by the National Science Foundation of China(NSFC)(11575196,11575197,11335001,11405053)the support of NSFC(11261130311)(CRC 110 by DFG and NSFC)
文摘We propose a novel type of interpolating field operator, which manifests the hybrid-like configuration that the charm quark-antiquark pair recoils against gluonie degrees of freedom. A heavy vector charmonium-like state with a mass of 4.33（2） GeV is disentangled from the conventional charmonium states in the quenched approximation. This state has affinity for the hybrid-like operators but couples less to the relevant quark bilinear operator. We also try to extract its leptonic decay constant and give a tentative upper limit that it is less than one tenth of that of J/ψ, which corresponds to a leptonic decay width about dozens of eV. The connection of this state with X（4260） is also discussed.
基金Supported by National Natural Science Foundation of China (11125525)
文摘Recently, the LHCb experiment announced 3.5σ evidence for direct CP violation in D0 decay by looking at the difference between A CP （D0 → K＋ K- ） and A CP （D0 →π＋ π- ）. This is the first evidence of CP violation in a charm system, which may indicate new physics beyond the Standard Model. Motivated by this measurement, we review rare processes in charmonium decay, especially, the weak decay, C or P violated decay, and lepton flavor violated decays. In case the new physics appears in charm sector, these rare decays of charmonium states will provide an opportunity to search for significant contributions from physics beyond the Standard Model. With huge J/ψ and ψ（2S） samples in BES experiment, the rare decays may be feasible.
文摘We report recent results on charmonium spectroscopy and decay from the CLEO-c experiment at the Cornell electrompositron storage ring accelerator, CESR. Most of the results are based on the analysis of 54 pb-1 of luminosity collected at the ψ（2S） resonance, corresponding to 27 M ψ（2S） decays. We concentrate on radiative decays of ψ（2S） and J/ψ, on two-body mesonic decay of XcJ, on hadronic decay of the he, and on higher multipoles in the two-photon cascade ψ（2S）→γχcJ, XcJ→γJ/ψ.
基金Supported by National Natural Science Foundation of China (10491300,10225524,10225525,10425523,10625524,10521003,10821063,10825524)Chinese Academy of Sciences (KJ 95T-03)+2 种基金100 Talents Program of CAS (U-11,U-24,U-25)Knowledge Innovation Project of CAS (U-602,U-34 (IHEP))National Natural Science Foundation of China (10225522 (Tsinghua University))
文摘Using ～ 14 × 10^6 ψ（2S） and ～ 58 × 10^ J/ ψ data collected at BES Ⅱ/BEPC, the branching fraction of ψ（2S）→Ω-Ω^＋ is measured with about 5a statistical significance. The A electric dipole and ∧ decay parameter are studied using the decay J/ψ →∧∧→ ppπ^＋π^-. Using （106±3）× 10^6 ψ（2S） decays collected at BESⅢ/BEPC Ⅱ, we have obtained some interesting physics results. The branching fractions of XcJ→π^0π^0, ηη are measured with precision improved. The mass and width of he（l^1P1） state, together with the branching fractions of Br（ψ（2S） →π^0hc） and Br（hc →γηc） are the first measurements. Surprisingly, the decays of Xc1→φφ, ωω, and ωφ are firstly observed in BESⅢ data.
基金National Natural Science Foundation of China(10775142)and 100 Talents Program of CAS(U-25)
文摘The cross sections for e^＋e^- →π^＋ π^-J/ψ, π^＋π^-ψ（2S）, K^＋K^-J/ψ, DD1D^0D1-π^＋ ＋c.c., D^＊D＋c.c., and D^＊D^＊ are measured using data sample collected on or near the T（4S） resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y（4260）, is observed in π^＋π^-J/ψ final state. In addition, there is another cluster of events at around 4.05 GeV/c^2. Two resonant structures are observed in the π^＋π^-ψ（2S） invariant mass distribution, one at 4361±9±9 MeV/c^2 with a width of 74±15±10 MeV/c2, and another at 4664 ±11±5 MeV/c2 with a width of 48±15±3 MeV/c^2. The rich structures observed in all these final states indicate that our understanding of the vector charmonium states above the open charm threshold is still poor, let alone the other possible dynamics such as charmonium hybrids or final state re-scattering and so on.
文摘We present a search for new charmonium like states in e^＋e^- annihilation using the initial-state radiation and the process e^＋e^- →J/ψ D（^＊）D（^＊）. The analyses are based on a huge data sample recorded near the T（4S） resonance with the Belle detector at the KEKB e^＋e^- asymmetric-energy collider.
基金Supported by National Natural Science Foundation of China(11175073,11005129,11035006)Ministry of Education of China(FANEDD(200924)+2 种基金DPFIHE(20090211120029)NCET(NCET-10-0442)Fundamental Research Funds for Central Universities and West Light Foundation of The Chinese Academy of Sciences
文摘The initial single pion emission （ISPE） mechanism is applied to the processes r（5S）→πB（＊）B-（＊）, whose details have been recently reported at ICHEP2012, and we obtain reasonable agreement with Bell＇s measurements; that is, we succeed in reproducing the enhancement structures of Zb（10610） and Zb（10650）. Inspired by this success, we also predict the corresponding enhancement structures in open charm oue-pion decays of higher charmonia near the thresholds of D＊D- and D＊D-＊.
文摘The line shapes to observe ηc in charmonium transitions, i.e., ψ（2S）, J/ψ→γηc, are investigated. The ηc line shapes in exclusive decays or by observing the inclusive photon spectrum are given. The sensitivities to measure the ηc resonance parameters are also evaluated. With more than two thousand ηc events observed, the precision of the ηc decay width measurement will be improved by better than 3%. However, the uncertainties associated with the ηc modified line shapes will dominate the systematic errors and this will prohibit precision mass and width measurements.
基金Supported by National Natural Science Foundation of China(11175111)
文摘The φ-charmonium dissociation reactions in hadronic matter are studied.Unpolarised cross sections for ФJ/ψ → Ds^-Ds^＋, ФJ/ψ →Ds^＊-Ds^＋ or Ds^-Ds^＊＋, ФJ/ψ →Ds^＊-Ds^＊＋, Фψ′→Ds^＊-Ds^＋, Фψ′→ Ds^＊-Ds^＋ or Ds^-Ds^＊＋,Фψ′→Ds^＊-Ds^＊＋,Фχc →Ds^-Ds^＋, Фχc→Ds^＊-Ds^＋ or Ds^-Ds^＊＋ and Фχc → Ds^＊-Ds^＊＋ are calculated in the Born approximation,in the quark-interchange mechanism and with a temperature-dependent quark potential.The potential leads to remarkable temperature dependence of the cross sections.With the cross sections and the Ф distribution function we calculate the dissociation rates of the charmonia in interactions with the Ф meson in hadronic matter.The dependence of the rates on temperature and charmonium momentum is relevant to the influence of Ф mesons on charmonium suppression.
基金Supported by National Natural Science Foundation of China (10675131,10491306)Chinese Academy of Sciences (KJCX3-SYW-N2)Ministry of Science and Technology of China (2009CB825200)
文摘We report the progress on understanding some of those existing puzzles in charmonium decays.We show that the intermediate meson loops （IML） as a long-distance transition mechanism will provide novel insights into these issues.In particular,we show that the IML mechanism would be essentially important for understanding the ψ（3770） non-DD decays.We also comment that such a mechanism is correlated with the Okubo-Zweig-Iizuka （OZI） rule evasions in charmonium hadronic decays.
基金supported in part by the National Science Foundation of China(NSFC)(11335001,11275169,11405178,11935017,11575196,11875169,11775229)It is also supported in part by the DFG and the NSFC(11261130311)through funds provided to the Sino-Germen CRC 110 symmetries and the Emergence of Structure in QCD+1 种基金This work is also funded in part by National Basic Research Program of China(973 Program)(2015CB856700).M.Gong and Z.Liu are partially supported by the Youth Innovation Promotion Association of CAS(2013013).This work is also supported by the Scientific Research Program Funded by Shaanxi Pro-vincial Education Department(19JK0391)Natural Science Basic Research Plan in Shaanxi Province of China(2019JM-001)。
文摘This exploratory study computes two-photon decay widths of pseudo-scalar(ηc)and scalar(χc0)charmonium using two ensembles of Nf=2 twisted mass lattice QCD gauge configurations.The simulation is performed using two lattice ensembles with lattice spacings a=0.067 fm with size 323×64 and a=0.085 fm with size 243×48.The decay widths for the two charmonia are obtained within the expected ballpark,but are however smaller than the experimental ones.Possible reasons for these discrepancies are discussed.
基金supported by the Spanish Ministerio de Ciencia e Innovación(MICINN)and the European Regional Development Fund(ERDF)under Contract PID2020-112777 GB-I00by the EU STRONG-2020 Project under the Program H2020-INFRAIA-2018–1 with Grant Agreement No.824093+4 种基金by Generalitat Valenciana under Contract PROMETEO/2020/023by the Chinese Academy of Sciences under Grant No.XDB34030000by the National Natural Science Foundation of China(NSFC)under Grants No.12125507,No.11835015,No.12047503,and No.11961141012by the NSFC and the Deutsche Forschungsgemeinschaft(DFG)through the funds provided to the Sino-German Collaborative Research Center TRR110“Symmetries and the Emergence of Structure in QCD”(NSFC Grant No.12070131001,DFG Project-ID 196253076)M.A.is supported by Generalitat Valenciana under Grant No.CIDEGENT/2020/002.
文摘We propose that the X(3915)observed in the J/w channel is the same state as the Xe2(3930),and the X(3960),observed in the D,D,channel,is an S-wave D,D,hadronic molecule.In addition,the jpC=0^(++)component in the B^(+)→D^(+)D K^(+)assigned to the X(3915)in the current Review of Particle Physics has the same origin as the X(3960),which has a mass around 3.94 GeV.To check the proposal,the available data in the DD and D,D,channels from both B decays andγγfusion reaction are analyzed considering both the DD-D,D,-D'D'-D,D,coupled channels with o^(++)and a 2^(++)state introduced additionally.It is found that all the data in different processes can be simultaneously well reproduced,and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73,3.94,3.99 and 4.23 Gev,respectively.The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons.
