Related papers: The Exotic XYZ Charmonium-like Mesons
We study heavy hadron spectroscopy near heavy meson thresholds. We employ heavy pseudoscalar meson P and heavy vector meson P* as effective degrees of freedom and consider meson exchange potentials between them. All possible composite…
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…
I discuss some recent discoveries in the spectroscopy of the charmonium-like resonances, and some of their theoretical interpretations are reviewed.
Exotic charmonium and bottonomium resonances recently discovered are discussed and interpreted as diquark-antidiquark states containing a pair of charm quarks and a pair of light, up and down, quarks. Successes, shortcomings and predictions…
The original charmonium two-body problem, like the $c\bar c$ structure of the $J/\psi$ meson, has become more involved in the last few years with the discovery of new resonances such as the tentative molecular state $X(3872)$ or the…
We study the spectroscopy of the states which defy conventional $c\bar{c}$ charmonium and $b\bar{b}$ bottomonium interpretation respectively, and are termed as exotic states. In August 2003 a state X(3872), was discovered [K. Abe\textit{\…
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 $\bar cc…
The charmonium-like states, Y(4260), Y(4350), produced via initial state radiation, as well as the X(3872), and Y(3940), produced in B meson decays from the BABAR B-factory are reviewed. These mesons do not seem consistent with conventional…
I classify exotic hadrons into two types, "genuine" and "hidden" exotics, and propose that the "hidden" exotics would be interpreted as "chiralons" in the ~U(12)_SF times O(3,1)_L-classification scheme of hadrons. Based upon this conjecture…
The recent observation of higher quark combinations, tetraquarks and pentaquarks, is a strong indication of more exotic hadrons. Using Z_{2} and Z_{3} symmetries and standard model data, a general quark combination producing new hadronic…
The newly found states Y(4260), Y(4361), Y(4664) and Z$^\pm$(4430) stir broad interest in the study of spectroscopy in a typical charmonium scale. The Y(4260) which was observed earlier has been interpreted as hybrid, molecular state, and…
Lots of charmonium-like structures have been observed in the last two decades. Most of them have quantum numbers that can be formed by a pair of charm and anticharm quarks, thus it is difficult to unambiguously identify the exotic ones…
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…
The BESIII and the LHCb became the leading experiments in the study of the exotic states after the Belle and BaBar experiments finished their data taking in the first decade of this century. We review the progress in the study of the XYZ…
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…
Several states that couple to one light-meson and a heavy-charmonium are recently reported, including the $Z_c(3900)$ and $Z_c(4020)$. These states cannot be interpreted within the constituent quark-model of mesons, and are good candidates…
I give a brief account of current topics in description of exotic multiquark mesonic resonances with hidden heavy ($c$ or $b$) flavor, the so-called XYZ states, in terms of hadronic molecules and hadro-quarkonium systems. Also discussed are…
We present a new dynamical picture that identifies the formation of the exotic $\bar c c$-containing states $XY \! Z$ with the confinement-induced hadronization of a rapidly separating pair of a compact diquark and antidiquark. This picture…
Quantum Chromodynamics, the theory of strong interactions, predicts several types of bound states. Among them are mesons ($q\bar{q}$) and baryons ($qqq$), which have been the only states observed in experiments for years. However, in the…
In this Letter we interpret the Y(4260), a state recently discovered by the BaBar Collaboration that has a mass within the range of conventional charmonium states, as having a molecular-state structure. In our scheme this molecular-like…