Related papers: From $J/\psi$ to LHCb pentaquark
An amplitude analysis of $B^-\to J/\psi\Lambda\bar{p}$ decays is performed using about 4400 signal candidates selected on a data sample of $pp$ collisions recorded at center-of-mass energies of 7, 8 and 13 TeV with the LHCb detector,…
The observations of fully-charm tetraquark states in the LHCb, CMS and ATLAS experiments suggested the existence of the hadronic molecules of two-charmonium states, which may also imply bound states in the three-charmonium systems. In this…
We calculate the mass spectrum of the $S$-wave fully-charmed tetraquark resonant states $cc\bar c\bar c $ in the nonrelativistic quark model, which successfully describes the charmonium spectrum. The four-body system is solved with the…
We investigate the quantum numbers of the pentaquark states $\textrm{P}_{\textrm{c}}^{+}$, which are composed of four (three flavors) quarks and an antiquark, by analyzing their inherent nodal structure in this paper. Assuming that the four…
Recently observed spectrum of $P_c$ states exhibits a strong link to $\Sigma_c \bar{D}^{(*)}$ thresholds. In spite of successful molecular interpretations, we still push forward to wonder whether there exist finer structures. Utilizing the…
A selected survey is presented of the recent progress in hadron spectroscopy. This includes spin-singlet charmonium states, excitations of charmonium and open-charm mesons, double-charm baryons, and pentaquark candidates. Models proposing…
The $P_c(4380)^+$ and $P_c(4450)^+$ states recently discovered at LHCb have masses close to several relevant thresholds, which suggests they can be described in terms of meson-baryon degrees of freedom. This article explores the…
The last few years have witnessed a renaissance in the spectroscopy of heavy quarks. Several long elusive states have now been firmly identified, and several unexpected states have been reported by the high luminosity experiments at Belle,…
Encouraged by the observation of the pentaquark states $P^+_c(4380)$ and $P^+_c(4450)$, we propose a novel color flux-tube structure, pentagonal state, for pentaquark states within the framework of color flux-tube mode involving a five-body…
Recently, Belle Collaboration reported a new exotic state $Y(4620)$ with mass at 4625.9 MeV in the positronium annihilation process. Inspired by experiment, we study the tetraquark system $c\bar{s}s\bar{c}$ with quantum numbers…
Motivated by the LHCb's recent confirmation of $Z_1(4475)$ as the $J^P=1^+$ resonance, we investigate various exotic interpretations of $Z_1(4475)$, which may be an axial vector tetraquark state, the P-wave excitation of the S-wave $D_1…
The B factories provide a unique playground for studying the properties of conventional and exotic charmonium states. We present recent results in initial state radiation and two-photon fusion, obtained using the full data set collected by…
The charm quark density-density correlation is calculated for $1S$ and $1P$ conventional charmonia and $J^{PC}=1^{-+},0^{+-}$ charmoniumlike states from lattice QCD and are interpreted as spatial wave functions of these states with some…
Many newly discovered mesons behave like $\ccbar$ charmonium states in that they preferentially decay into final states that contain a $c$- and a $\bar{c}$-quark, but do not fit expectations for any of the unfilled levels of the…
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…
The bottom-charmed ($B_c$) mesons are more stable than their charmonium ($c\bar c$) and bottomium ($b\bar b$) partners because they cannot annihilate into gluons. However, the low production cross-sections and signal-to-background ratios…
We study in the framework of a constituent quark model the possible contributions of molecular structures to the XYZ charmonium like states. We analyze simultaneously the $c\bar{c}$ structures and the possible molecular components in a…
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.
Narrow Xi-pi+- and Xi-bar+pi+- resonances produced by quasi-real photons have been searched for by the COMPASS experiment at CERN. The study was stimulated by the recent observation of an exotic baryonic state decaying into Xi-pi-, at a…
We study the nature of the recently observed $P_{cs}(4459)$ by the LHCb collaboration by employing three methods based on the elastic effective-range expansion and the resulting size of the effective-range, the saturation of the…