Related papers: $Y(4260)$ as the first $S$-wave open charm vector …
The past four years has witnessed the renaissance of the hadron spectroscopy. Many interesting new hadron states were discovered experimentally, some of which do not fit into the quark model easily. I will give a concise overview of these…
Hadrons and their distributions are the most direct observables in experiment, which would shed light on the non-perturbative mystery of quantum chromodynamics (QCD). As the result, any new hadron will challenge our current knowlege on the…
The mass of $P$-wave $cs$-scalar-diquark $\bar{c}\bar{s}$-scalar-antidiquark state is computed in the framework of QCD sum rules. The result $4.69\pm0.36{GeV}$ is in good agreement with the experimental value of Y(4660) but higher than…
In recent years many vector charmonium(-like) states were reported by different electron-positron collider experiments above $4.2$ GeV. However, so far, there not only exists sizable tension in the parameters of those states, but there is…
The $Z_{c}(3900)^\pm/Z_c(3885)^\pm$ and $Z_{c}(4020)^\pm$ are two charmonium-like structures discovered in the $\pi J/\psi$ and $D^\ast\bar D^{(\ast)}+h.c.$ invariant mass spectra. Their nature is puzzling due to their charge, which forces…
We discuss possible options for interpreting the newly observed state Y(4140) by the CDF collaboration in $B^+\to J/\psi\phi K^+$ decay above the $J/\psi\phi$ threshold, and argue that it is more likely to be a $D_s^*$-$D_s^*$ molecular…
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…
The di-electron widths of $\psi(4040)$, $\psi(4160)$, and $\psi(4415)$, and their ratios are shown to be in good agreement with experiment, if in all cases the $S-D$ mixing with a large mixing angle $\theta\approx 34^\circ$ is taken.…
We study the well-known resonance $\psi(4040)$, corresponding to a $3^{3}S_{1}$ charm-anticharm vector state $\psi(3S)$, within a QFT approach, in which the decay channels into $DD$, $D^{\ast}D$, $D^{\ast}D^{\ast}$, $D_{s}D_{s}$ and…
Many mesons with properties incompatible with a $\bar cc$ structure have already been discovered, e.g. the $Z_c$ mesons with isospin 1. We investigate the spectrum of exotic charmonium-like mesons using lattice QCD. The focus is on $\bar cc…
Using data samples with an integrated luminosity of 5.85~fb$^{-1}$ collected at center-of-mass energies from 4.61 to 4.95 GeV with the BESIII detector operating at the BEPCII storage ring, we measure the cross section for the process…
Very recently, the LHCb Collaboration at the Large Hadron Collider at CERN observed new resonance $X(4630)$. The $X(4630)$ is decoded as a charmoniumlike molecule with hidden-strange quantum number well in the one boson exchange mechanism.…
The charmed meson pair $(\frac{3}{2})^+$ and anti-$(\frac{1}{2})^-$, i.e. $D_1(2420)\bar D+c.c.$, $D_1(2420)\bar D^*+c.c.$, $D_2(2460)\bar D^*+c.c.$, can couple to states with vector quantum number $J^{PC}=1^{--}$ and exotic quantum number…
In this work, we have investigated whether Y(4260) and ${\rm Z^{+}_2(4250)}$ could be ${\rm D_1D}$ or ${\rm D_0D^{*}}$ molecules in the framework of meson exchange model. The off-diagonal interaction induced by $\pi$ exchange plays a…
In 2017, the BESIII Collaboration announced the observation of a charged charmonium-like structure in the $\psi(3686)\pi^\pm$ invariant mass spectrum of the $e^+ e^- \to \psi(3686) \pi^+ \pi^-$ process at different energy points, which…
Since 2003 several states in the charmonium mass region were discovered. While in the conventional c c-bar spectrum some states are missing, the number of states observed up to now is larger than empty spaces in the c c-bar spectrum. This,…
We predict the existence of two novel bottomoniumlike states, $Y(10600)$ and $Y(10650)$, as either the $P$-wave $B^{(*)}\bar{B}^{(*)}$ bound state or resonance close to the $B\bar{B}^{*}$ and $B^{*}\bar{B}^{*}$ thresholds, respectively,…
The heavy hadron spectrum is constrained by symmetries, of which two of the most important ones are heavy-quark spin and SU(3)-flavor symmetries. Here we argue that in the molecular picture the $Y(4230)$ (or $Y(4260)$), the $Y(4360)$ and…
Inspired by the observation of the $P_{cs} (4459)$ state by LHCb recently, we reexamine the results of the interaction of the $J/\psi \Lambda$ channel with its coupled channels, exploiting the coupled channel unitary approach combined with…
Threshold enhancements like the X(4660) and depletion effects as the X(4260) are listed as c-cbar resonances in the Particle Data Group tables. We will discuss these observations, and present a list of further c-cbar enhancements, which are…