Related papers: Strange hadrocharmonium
It is suggested that the resonance $\psi(3770)$ may contain a sizeable ($O(10%)$ in terms of the probability weight factor) four-quark component with the up- and down- quarks and antiquarks in addition to the $c {\bar c}$ pair, which…
Flavor-exotic tetraquark mesons have recently been observed in the heavy-quark pair sectors of QCD, including two isospin multiplets in the b b-bar sector, Z_b(10610) and Z_b(10650), and one isospin multiplet in the c c-bar sector,…
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,…
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…
We present a selection of recent results from the BESIII collaboration, including both charmonium and $D$ meson physics. We first discuss the observation of a charged, charmonium-like state, the $Z_c(3900)$. Conventional charmonium topics…
Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $\Xi^-_b\rightarrow J/\psi K^- \Lambda$ to search for the…
The LHCb Collaboration has recently reported the observation for the first time of a spin-$3$ resonance in the heavy quark sector. They have shown that the $\bar{D}^{0}K^{-}$ structure seen in the $B_{s}^{0}\to \bar{D}^{0}K^{-}\pi^{+}$…
Charm meson molecule (c\bar n)(n\bar c) assignments for the supercharmonium state Z(4475) are considered, both on general grounds and in the context of specific pion exchange models. Two possible charm molecule assignments for the JP = 1+,…
In the framework of a nonrelativistic potential quark model, we investigate the mass spectrum of the $1S$-wave charmed-strange tetraquark states of $cn\bar{s}\bar{n}$ and $cs\bar{n}\bar{n}$ ($n=u$ or $d$) systems. The tetraquark system is…
Recently a novel hadronic state of mass 6.9 GeV, that decays mainly to a pair of charmonia, was observed in LHCb. The data also reveals a broader structure centered around 6490 MeV and suggests another unconfirmed resonance centered at…
Motivated by the recent discovery of the hidden charm exotic state with strangeness by the BESIII and LHCb Collaborations, we study the $S$ wave strange hidden bottom tetraquark in two kinds of quark models. Both meson-meson and…
The first observation of exotic states with a new quark content $c \bar{c} u \bar{s}$ decaying to the $J/\psi K^+$ final state is reported with high significance from an amplitude analysis of the $B^+ \to J/\psi \phi K^+$ decay. The…
The LHCb Collaboration at the Large Hadron Collider at CERN discovered two pentaquark states $P_c(4380)$ and $P_c(4450)$. These two hidden-charm states are interpreted as the loosely bound $\Sigma_c(2455)D^*$ and $\Sigma_c^*(2520)D^*$…
Belle Collaboration has recently observed a new state, the X(4160), in the process of double charm production $e^+e^-\to J/\psi+X(4160)$ followed by $X(4160)\to D^*\bar{D^*}$. We discuss possible interpretations for the X(4160) based on the…
By using QCD Sum Rules, we found that the charged hidden charm tetraquark $[c u][\bar{c} \bar{d}]$ states with $ J^P = 1^-$ and $ 2^+$, which are possible quantum numbers of the newly observed charmonium-like resonance $Z_c(4025)$, have…
The $B_c ^+$ family of $(c\bar{b})$ mesons with beauty and charm is of special interest among heavy quarkonium systems. The $B_c ^+$ mesons are intermediate between $(c\bar{c})$ and $(b\bar{b})$ states both in mass and size, so many…
A review of recent experimental developments concerning the $X$, $Y$ and $Z$ charmonium-like exotic states.
This contribution reviews some recent developments in charmonium spectroscopy, and discusses related theoretical predictions. The spectrum of states, strong decays of states above open charm threshold, electromagnetic transitions, and…
There have been numerous developments in hadron spectroscopy over the past year. In this brief review I focus on two general areas. In the first I give an update on hadrons with b-quarks. Their properties are in textbook agreement with QCD…
Different from the usual tetraquark assignment to charged $Z_c(3885)$ and $Z_c(4025)$ charmoniumlike structures, in this letter we propose a universal non-resonant explanation to decode these $Z_c$'s, which is based on a special dynamical…