Hadronic Spectrum - Multiquark States

Abstract

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 conventional $\ccbar$ spectrum. There is a growing suspicion that at least some of these states are {\it exotic}, {\it i.e.} have a substructure that is more complex than the quark-antiquark mesons of the classical constituent quark model. Some of these candidate states have a non-zero electric charge and, thus, a minimal quark content of $\ccbar u\bar{d}$ or $\ccbar d\bar{u}$. In addition, states with similar properties have been observed in the $b$- and $s$-quark sectors. In this report, the experimental situation is briefly reviewed.

8 pages, 9 figures, plenary talk at PANIC 2008, Nov. 9-14, 2008 Eilat, Israel. (Uses elsart1p.cls.)

References in corpus (24)

• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Observation of Two Resonant Structures in e+e- to pi+ pi- psi(2S) via Initial State Radiation at Belle
• Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle
• The Exotic XYZ Charmonium-like Mesons
• Observation of two resonance-like structures in the pi+ chi_c1 mass distribution in exclusive B0-bar --> K- pi+ chi_c1 decays
• Evidence for X(3872) --> psi(2S) gamma in B+/- --> X(3872) K+/- decays, and a study of B --> ccbar gamma K
• Search for new charmonium states in the processes e+ e- --> J/psi D(*) D(*) at sqrt{s} ~ 10.6 GeV
• Reconciling the X(3872) with the near-threshold enhancement in the D^0\bar{D}^{*0} final state
• Search for the Z(4430)^- at BABAR
• Observation of Y(3940) -> J/psi omega in B -> J/psi omega K at BABAR
• Measurement of the near-threshold $e^{+}{e}^{-}\to D\bar{D}$ cross section using initial-state radiation
• Observation of Y(2175) in $J/\psi \to \eta \varphi f_0(980)$
• Study of the $B\to X(3872)(\to D^{\ast 0}{\bar{D}}^0)K$ decay
• Determination of the $\psi (3770)$, $\psi (4040)$, $\psi (4160)$ and $\psi (4415)$ resonance parameters
• Decays of the X(3872) and ${\chi }_{c1}(2P)$ charmonium
• Y(2175): Distinguish Hybrid State from Higher Quarkonium
• How Resonances can synchronise with Thresholds
• The Effects of Charged Charm Mesons on the Line Shapes of the X(3872)
• Observation of an enhancement in e+e- to Upsilon(1S)pi+pi-, Upsilon(2S)pi+pi-, and Upsilon(3S)pi+pi- production near sqrt{s}=10.89 GeV at Belle
• Observation of an enhancement in $e^{+}{e}^{-}\to {\rm Y}(1S){\pi }^{+}{\pi }^{-}$, ${\rm Y}(2S){\pi }^{+}{\pi }^{-}$, and ${\rm Y}(3S){\pi }^{+}{\pi }^{-}$ production around $\sqrt{s}=10.89$ GeV at Belle
• Wigner crystal vs. Friedel oscillations in the 1D Hubbard model
• Determining the upper limit of Gamma_{ee} for the Y(4260)
• Searching for the Bottom Counterparts of X(3872) and Y(4260) via ${\pi }^{+}{\pi }^{-}{\rm Y}$
• Isospin properties of the X state near the D {\bar D}^{*} threshold

Cited by in corpus (25)

• New Charmonium States in QCD Sum Rules: a Concise Review
• The Y(3940), Z(3930) and the X(4160) as dynamically generated resonances from the vector-vector interaction
• QCD Sum Rules Approach to the $X,Y$ and $Z$ States
• Tetraquark interpretation of the BELLE data on the anomalous ${\rm Y}(1S){\pi }^{+}{\pi }^{-}$ and ${\rm Y}(2S){\pi }^{+}{\pi }^{-}$ production near the ${\rm Y}(5S)$ resonance
• Lineshapes for composite particles with unstable constituents
• Study of $B{\bar{B}}^{\ast }$ and $B^{\ast }{\bar{B}}^{\ast }$ interactions in $I=1$ and relationship to the $Z_b(10610)$, $Z_b(10650)$ states
• The $P$-wave $[cs][\bar{c}\bar{s}]$ tetraquark state: Y(4260) or Y(4660)?
• Exotic $1^{--}$ States in QCD Sum Rules
• Axial Vector $J^{PC}=1^{++}$ Charmonium and Bottomonium Hybrid Mass Predictions with QCD Sum-Rules
• Mass Predictions for Pseudoscalar $J^{PC}=0^{-+}$ Charmonium and Bottomonium Hybrids in QCD Sum-Rules
• Mass spectrum of the scalar hidden charm and bottom tetraquark states
• Y(4260) as a mixed charmonium-tetraquark state
• Could $Y_b(10890)$ be the P-wave $[bq][\bar{b}\bar{q}]$ tetraquark state?
• Mass spectrum of the axial-vector hidden charmed and hidden bottom tetraquark states
• Mass spectrum of the vector hidden charm and bottom tetraquark states
• Mass Predictions of Vector ($1^{--}$) Double-gluon Heavy Quarkonium Hybrids from QCD Sum Rules
• Exotic Charmonium and Bottomonium-like Resonances
• Four-quark structure of the excited states of heavy mesons
• QCD quark cyclobutadiene and light tetraquark spectrum
• $J^{PC}=1^{++}$ heavy hybrid masses from QCD sum-rules
• Gluonic Hidden-charm Tetraquark States
• No Radial Excitations in Low Energy QCD. I. Diquarks and Classification of Mesons
• Hadron Spectroscopy Results from Belle
• Looking for meson molecules in B decays
• Diquark-Antidiquark Interpretation of Mesons