Related papers: Newly observed $X(4630)$: a new charmoniumlike mol…
A number of candidate multiquark hadrons, i.e., particle resonances with substructures that are more complex than the quark-antiquark mesons and three-quark baryons that are prescribed in the textbooks, have recently been observed. In this…
To illustrate the campaign to extend our knowledge of the charmonium spectrum, I focus on a puzzling new state, $X(3872) \to \pi^+\pi^- J/\psi$. Studying the influence of open-charm channels on charmonium properties leads us to propose a…
The LHCb collaboration has recently announced the discovery of two hidden-charm pentaquark states with also strange quark content, $P_{cs}(4338)$ and $P_{cs}(4459)$; its analysis points towards having both hadrons isospin equal to zero and…
Mesonic resonances are generally observed in data as narrow, moderately broad, or wide peaks in scattering or production processes. In the eyes of nearly all experimentalists, any suchlike bump is a true resonance as soon as its statistical…
We first present a non-resonant description to charmonium-like structure $Y(4360)$ in the $\psi(2S)\pi^+\pi^-$ invariant mass spectrum of the $e^+e^-\to \psi(2S)\pi^+\pi^-$ process. The $Y(4360)$ structure is depicted well by the…
In the present article we report on evidence for hadronic molecule structures in the charmonium sector. In particular we discuss the Y(3940) and the recently observed Y(4140) as heavy hadron molecule states with quantum numbers $J^{PC} =…
Inspired by the newly observed $P_{\psi s}^\Lambda(4338)$ and the reported $P_{cs}(4459)$, we indicate the existence of the molecular-type characteristic mass spectrum for hidden-charm pentaquark with strangeness. It shows that the…
We review how quark models are able to describe the phenomenology of the charm meson sector. The spectroscopy and decays of charmonium and open charm mesons are described in a particular quark model and compared with the data and the…
We apply a phenomenological Lagrangian approach to the radiative decay Y(4260) -> X(3872) + gamma. The Y(4260) and X(3872) resonances are considered as composite states containing both molecular hadronic and charmonium components. Having a…
The $\Lambda_c(2940)$, an open-charm baryon discovered in 2006, has sparked interest due to its ``low mass puzzle'', paralleling the $X(3872)$ in the charmoniumlike sector. Both states challenge conventional hadronic interpretations, with…
One of the most intriguing puzzles in hadron spectroscopy are the numerous charmonium-like states observed in the last decade, including charged states that are manifestly exotic. Over the years, the experiment $BABAR$ has extensively…
In recent years, lots of studies of charmonium decays have been performed at BESIII based on large data samples of $J/\psi$, $\psi(3686)$ and $\psi(3770)$. Recent results in searches for radiative transitions of $\psi(3770)$ and rare…
We have studied the loosely bound $D^*\bar{D}^*$ system. Our results indicate that the recently observed charged charmonium-like structure $Z_c(4025)$ can be an ideal $D^*\bar{D}^*$ molecular state. We have also investigated its pionic,…
BaBar and Belle have recently revived the interest in charmonium spectroscopy, discovering many unexpected resonances. In this review, I'll focus mostly on the states found in B decays and double $\ccbar$. A better understanding of their…
The beauty hadron decays is unique laboratory to study charmonium and charmonium-like states, such as the $\chi_{c1}(3872)$ meson, other exotic states and the tensor D-wave $\psi_2(3823$) states. However the nature of many exotic…
Hidden-charm pentaquark-like $P_{\psi s}^\Lambda(4459)^0$ and $P_{\psi s}^\Lambda(4338)$ resonances are studied in a constituent quark model as molecular meson-baryon structures. Such states are found in the $J^P(I)=\frac{1}{2}^-(0)$…
Exotic charmonium-like states have been observed by various experiments over the last 15 years, but their nature is still under discussion. Photo-(muo)production is a new promising instrument to study them. COMPASS, a fixed target…
We study the decay of $\Lambda_b\to J/\psi\Lambda\phi$ by taking into account the intermediate resonances $X(4140)$, $X(4160)$, and $P_{cs}(4459)$. In addition to the peak of the $X(4140)$, we also find a bump structure around 4160 MeV…
The positive parity $\chi_{cJ}(2P)$ charmonium states are expected to lie around the 3.9 GeV/$c^2$ energy region, according to the predictions of quark models. However, a plethora of states with difficult assignment and unconventional…
Production of J/$\psi$ from nucleus-nucleus reactions depends sensitively on the dissociation cross section with light hadrons. Effective lagrangian methods are used to describe the hadronic degrees of freedom, including strangeness and…