Related papers: Charged Exotic Charmonium States
The discovery of numerous new charmonium-like structures since 2003 have revitalized interest in exotic meson spectroscopy. These structures do not fit easily into the conventional charmonium model, and proposals like four-quark states,…
We revise and extend expectations for the properties of charmonium states that lie above charm threshold, in light of new experimental information. We refine the Cornell coupled-channel model for the coupling of c-cbar levels to two-meson…
A model of hybrid meson structure based on the QCD Hamiltonian in Coulomb gauge and the use of a single constituent quasigluon is applied compute hadronic decays of mesons with exotic quantum numbers, $0^{+-}$ and $2^{+-}$. These correspond…
Charmonium is a bound state of a charmed quark and a charmed antiquark, and a charmoniumlike state is a resonant structure that contains at least a charmed quark-antiquark pair but has properties that are incompatible with a conventional…
Using the QCD sum rules we test if the charmonium-like structure Y(4260), observed in the $J/\psi\pi\pi$ invariant mass spectrum, can be described with a $J/\psi f_0(980)$ molecular current with $J^{PC}=1^{--}$. We consider the…
In this article, we perform a systematic study of the mass spectrum of the scalar doubly charmed and doubly bottom tetraquark states using the QCD sum rules.
Recently, a QCD sum-rule analysis of tetraquark molecular states has been published, having the objective of demonstrating that our previously formulated tetraquark-adequate QCD sum rules are not correct. This comment brings to the…
By analyzing existing data on pseudoscalar charmonium decays, we obtain the ratio of the branching fractions of $\eta_c(2S)$ and $\eta_c$ decays into ten different final states with light hadrons. For the first time, we test the two…
We review recent studies on exotic states at the Belle experiment. The results include: (1) The measurement of the cross sections of $\gamma \gamma \to \omega \phi$, $\phi\phi$, and $\omega \omega$ for masses that range from threshold to…
Since 2003 many charmonium-like states were observed experimentally. Especially those charged charmonium-like $Z_c$ states and bottomonium-like $Z_b$ states cannot be accommodated within the naive quark model, which are good candidates of…
It has been recently suggested that the charged charmoniumlike resonances $Z_c(4100)$ and $Z_c(4200)$ are two states of hadrocharmonium, related by the charm quark spin symmetry in the same way as the lowest charmonium states $\eta_c$ and…
In the framework of the color-magnetic interaction, we systematically investigate the mass splittings of the $QQ\bar{Q}\bar{q}$ tetraquark states and estimated their rough masses in this work. These systems include the explicitly exotic…
We systematically investigate the mass spectrum and two-body open-charm strong decays of charmonium states in a coupled-channel model where the $^3P_0$ quark-antiquark pair creation mechanism is employed. The results of masses, mass shifts,…
Orbitally excited L=1 charm mesons are studied by QCD sum rules in the framework of heavy quark effective theory. The meson masses and the strong decay widths are obtained. This talk is based on our works of refs. 1 and 2 collaborated with…
The masses and decay widths of charmonium states are studied in the presence of strong magnetic fields. The mixing between the pseudoscalar and vector charmonium states at rest is observed to lead to appreciable negative (positive) shifts…
The past decade witnessed the observation of several exotic charmonium-like resonances, some of which are manifestly non-qqbar mesons. We review one of the most popular interpretations of such states: the compact tetraquark in the…
The analyses of states with double $cs$ content and the search for exotics have recently gained much attention. The Belle experiment collected roughly 1 ab$^{-1}$ integrated luminosity data. While Belle II data-taking is in progress, we…
Observations of new charmonium(-like) and bottomonium(-like) states (sometimes refered to as "XYZ" states) at e+e- colliders have changed our picture of quarkonia systems as QCD bound states. Potential models with a linear confinement…
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…
Selected topics of exotics in leptonic machines are presented, including recent discovery of abnormal structures around the ppbar threshold and new information of the XYZ (charmonium-like) states.