We study charmonium （ccnn）,bottomonium （b bnn） and exotic （ccnn and bbnn） four-quark states by means of a standard non-relativistic quark potential model.We look for possible bound states.Among them we are able ...We study charmonium （ccnn）,bottomonium （b bnn） and exotic （ccnn and bbnn） four-quark states by means of a standard non-relativistic quark potential model.We look for possible bound states.Among them we are able to distinguish between meson-meson molecules and compact four-quark states.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 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
QCD-motivated models for hadrons predict an assortment of ＂exotic＂ hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These...QCD-motivated models for hadrons predict an assortment of ＂exotic＂ hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark baryons： the six-quark H-dibaryon~ and tetraquark, hybrid and glueball mesons. Despite extensive experimental searches, no unambiguous candidates for any of these exotic configurations have been identified. On the other hand, a number of meson states, one that seems to be a proton-antiproton bound state, and others that contain either charmed- anticharmed quark pairs or bottom-antibottom quark pairs, have been recently discovered that neither fit into the quark-antiquark meson picture nor match the expected properties of the QCD- inspired exotics. Here I briefly review results from a recent search for the H-dibaryon, and discuss some properties of the newly discovered states -the proton-antiproton state and the so-called XYZ mesons- and compare them with expectations for conventional quark-antiquark mesons and the predicted QCD-exotic states.展开更多
基金partially funded by Ministerio de Ciencia y Tecnología under Contract No.FPA2007-65748EUFEDER,and by Junta de Castilla y León under Contracts No.SA016A17 and GR12
文摘We study charmonium （ccnn）,bottomonium （b bnn） and exotic （ccnn and bbnn） four-quark states by means of a standard non-relativistic quark potential model.We look for possible bound states.Among them we are able to distinguish between meson-meson molecules and compact four-quark states.
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.
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.
文摘QCD-motivated models for hadrons predict an assortment of ＂exotic＂ hadrons that have structures that are more complex than the quark-antiquark mesons and three-quark baryons of the original quark-parton model. These include pentaquark baryons： the six-quark H-dibaryon~ and tetraquark, hybrid and glueball mesons. Despite extensive experimental searches, no unambiguous candidates for any of these exotic configurations have been identified. On the other hand, a number of meson states, one that seems to be a proton-antiproton bound state, and others that contain either charmed- anticharmed quark pairs or bottom-antibottom quark pairs, have been recently discovered that neither fit into the quark-antiquark meson picture nor match the expected properties of the QCD- inspired exotics. Here I briefly review results from a recent search for the H-dibaryon, and discuss some properties of the newly discovered states -the proton-antiproton state and the so-called XYZ mesons- and compare them with expectations for conventional quark-antiquark mesons and the predicted QCD-exotic states.
