相关论文: Newly observed $X(4630)$: a new charmoniumlike mol…
Hadron spectroscopy represented in the past a major tool for understanding the fundamental symmetries of strong forces. More recently, the interest on this topic has been revitalized by the discovery of new quarkonium-like resonances, that…
In this thesis, the QCD sum rules approach has been used to study the nature of the following charmonium resonances: Y(3930), Y(4140), X(4350), Y(4260), Y(4360) and Y(4660). There is a strong evidence that these states have non-conventional…
Recent experiments at the LHCb detector have once again raised the possibility that quark bags may exist containing more than three quarks. Specifically the LHCb collaboration points to evidence for hadronic resonances decaying into…
Vector charmonium states $J/\Psi$ and $\Psi'$ are copiously produced by $e^+e^-$ annihilations at the Beijing Electron Positron Collider (BEPC). Their decays provide an excellent place for studying excited nucleons and hyperons -- $N^*$,…
The hidden charm pentaquark state $P_c(4450)$ observed recently by the LHCb collaboration may be of molecular nature, as advocated by some unitary approaches that also predict pentaquark partners in the strangeness $S=-1$ sector. In this…
Using the QCD sum rule approach we study the X(4260) state assuming that it can be described by a mixed charmonium-tetraquark current with $J^{PC}=1^{--}$ quantum numbers. For the mixing angle around $\theta=(53.0 \pm 0.5)^0$, we obtain a…
The proximity of ${\rm Z}^+(4430)$ to the ${\rm D^{*}\bar{D}_1}$ threshold suggests that it may be a ${\rm D^{*}\bar{D}_1}$ molecular state. The ${\rm D^{*}\bar{D}_1}$ system has been studied dynamically from quark model, and state mixing…
An overview is given on recent progress in the study of quarkonium spectroscopy at the B-factories. In particular, an updated status report is presented of the long list of "charmonium-like" resonances newly discovered, whose assignment as…
The mass spectra of charmonium are investigated using a Coulomb plus linear (Cornell) potential. Gaussian wave function in position space as well as in momentum space are employed to calculate the expectation value of potential and kinetic…
The LHCb Collaboration announced the observation of three narrow structures consistent with hidden-charm pentaquark states. They are candidates of hadronic molecules formed of a pair of a charmed baryon and an anticharmed meson. Among them,…
To celebrate the 50th anniversary of the discovery of the J/{\psi}, the first charmonium state observed, I start with a brief review of major progresses on the QCD inspired quark potential model originated from charmonium spectrum.Then I…
After Y(4630) is discovered, theorists have given various explanations. We find that if Y(4630) is interpreted as the D-wave resonant state of $\Lambda_c \bar {\Lambda}_c$ system, the particle mass, decay width and all quantum numbers are…
In this work, we propose an unquenched mechanism for charmonium scattering that utilizes the internal structure of charmonium. By capturing light flavor quarks and anti-quarks from the vacuum, charm and anti-charm quarks form virtual…
We study the near-threshold $J/\psi$ meson production on protons and nuclei by considering incoherent direct non-resonant $K^-p \to {J/\psi}\Lambda$ and two-step resonant ${K^-}p \to P_{cs}(4459)^0 \to {J/\psi}\Lambda$ charmonium production…
I discuss the nature of the new charm and charmonium like states observed in the last few years and measurements that can test these assignments. In particular it appears that the X(3943) is the eta_c''(3^1S_0) which can be tested by…
We propose a new interpretation of the neutral and charged X, Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules. The latter would require a negative or zero…
Recent CMS observations in the di-$J/\psi$ invariant mass spectrum reveal new structures at 6638 MeV ($X(6600)$)) and 7134 MeV, and confirm the $X(6900)$ at 6847 MeV. These findings provide crucial insights into four-charm-quark matter. The…
We argue that relatively compact charmonium states, $J/\psi$, $\psi(2S)$, $\chi_c$, can very likely be bound inside light hadronic matter, in particular inside higher resonances made from light quarks and/or gluons. The charmonium state in…
I review the recent $B$-factory measurements of new states which, in some cases, exhibit Charmonium-like properties, and in other cases suggest the existence of a new spectroscopy. Several theoretical interpretations of the new states have…
In this talk we present some recent studies of multiquark components in the charmonium sector. We study the possible existence of compact four quark-states and meson-meson molecules in the charmonium spectroscopy.