New Hadron States

Abstract

The past four years has witnessed the renaissance of the hadron spectroscopy. Many interesting new hadron states were discovered experimentally, some of which do not fit into the quark model easily. I will give a concise overview of these states and their possible interpretations. Topics covered in this review are: (1) candidates of new light hadrons including $p\bar{p}$ threshold enhancement, X(1835), X(1576), $f_0(1810)$, recent candidates of the $1^{-+}$ exotic mesons, Y(2175), $p\bar{\Lambda }$ threshold enhancement etc; (2) charmed mesons including p-wave non-strange charmed mesons, $D_{sj}(2317)$ and $D_{sj}(2460)$, recent candidates of higher excited charmed mesons, $D_{sj}(2632)$ etc; (3) charmonium and charmonium-like states such as X(3872), Y(4260), X(3940), Y(3940), Z(3930) etc. The effect from the nearby S-wave open channels on the quark model spectrum above or near strong decay threshold is emphasized. Dynamical lattice simulations of $DK$ and $D^0{\bar{D}}^{\ast 0}$ scattering and the extraction of their phase shifts may help resolve the underlying structure of $D_{sj}(2317)$, $D_{sj}(2460)$ and X(3872).

Brief review, 29 pages, comments and suggestions welcome

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• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Evidence for Narrow S=+1 Baryon Resonance in Photo-production from Neutron
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• Observation of a Broad Structure in the ${\pi }^{+}{\pi }^{-}J/\psi$ Mass Spectrum around 4.26 GeV/$c^2$
• Observation of a Narrow Meson Decaying to Ds+pi0 at a Mass of 2.32 GeV/c^2
• Observation of the Narrow State $X(3872)\to J/\psi {\pi }^{+}{\pi }^{-}$ in $\bar{p}p$ Collisions at $\sqrt{s}=1.96 \TeV$
• The New Heavy Mesons: A Status Report
• Observation and Properties of the X(3872) Decaying to J/psi pi+ pi- in p-p(bar) Collisions at sqrt(s) = 1.96 TeV
• Isospin breaking of the narrow charmonium state of Belle at 3872 MeV as a deuson
• Observation of a Narrow Resonance of Mass 2.46 GeV/c^2 Decaying to D_s^*+ pi^0 and Confirmation of the D_sJ^* (2317) State
• Study of the B- --> J/psi K- pi+ pi- Decay and Measurement of the B- --> X(3872) K- Branching Fraction
• Chiral Multiplets of Heavy-Light Mesons
• Observation of String Breaking in QCD
• Implications of a DK Molecule at 2.32 GeV
• Observation of a near-threshold omega-J/psi mass enhancement in exclusive B-->K omega J/psi decays
• The D*0 D0bar threshold resonance
• Observation of a near-threshold enhancement in th p pbar mass spectrum from radiative J/psi-->gamma p pbar decays
• Resonances in $J/\psi \to \varphi {\pi }^{+}{\pi }^{-}$ and $\varphi K^{+}{K}^{-}$
• Charmonium levels near threshold and the narrow state $X(3872) \to π^{+}π^{-}\jpsi$
• Observation of the DsJ(2317) and DsJ(2457) in B decays
• Study of B- => D**0 pi-(D**0 => D(*)+ pi-) decays
• Interference and binding effects in decays of possible molecular component of X(3872)
• Can the X(3872) be a 1^{++} four-quark state?
• The X(3872) boson: Molecule or charmonium
• Charmonium Decays of $Y(4260), psi(4160), and psi(4040)
• Gluonic charmonium resonances at BaBar and Belle?
• Molecular States of Heavy Quark Mesons
• Four Quark Interpretation of Y(4260)
• Masses of heavy tetraquarks in the relativistic quark model
• Confirmation of the Y(4260) Resonance Production in ISR
• The Possible Interpretations of Y(4260)
• B Decays as Spectroscope for Charmed Four-quark States
• Observation of a Near-threshold $D^0{\bar{D}}^0{\pi }^0$ Enhancement in $B\to D^0{\bar{D}}^0{\pi }^{0}K$ Decay
• Observation of a resonance X(1835) in J/ψ--> γπ^+ π^- η^{\prime}
• Strong Decays of Strange Quarkonia
• Suppressed decay into open charm for the Y(4260) being an hybrid
• Understanding $D_{sJ}(2317)$
• New states above charm threshold
• Testing the Nature of the D_{sJ}^*(2317)^+ and D_{sJ}(2463)^+ States Using Radiative Transitions
• Hybrid Meson Decay Phenomenology
• A Structure at 2175 MeV in $e^{+}{e}^{-}\to \varphi f_0(980)$ Observed via Initial-State Radiation
• Observation of a New D_s Meson Decaying to D K at a Mass of 2.86 GeV/c^2
• Measurements of the $D_{sJ}$ resonance properties
• A Comprehensive Four-Quark Interpretation of D_s(2317), D_s(2457) and D_s(2632)
• Four-quark spectroscopy within the hyperspherical formalism
• Measurement of the Dipion Mass Spectrum in X(3872) -> J/Psi Pi+ Pi- Decays
• BABAR resonance as a new window of hadron physics
• Search for B+ --> X(3872) K+, X(3872) --> J/psi gamma
• Measurement of Masses and Widths of Excited Charm Mesons $D_2^{\ast }$ and Evidence for Broad States
• Reinterpreting several narrow `resonances' as threshold cusps
• Observation of exotic meson production in the reaction ${\pi }^{-}p\to {\eta }^{\prime }{\pi }^{-}p$ at 18 GeV/c
• Understanding the $D_{sJ}^{+}(2317)$ and $D_{sJ}^{+}(2460)$ with Sum Rules in HQET
• Is X(3872) a possible candidate of hybrid meson
• Open Charm and Beauty Chiral Multiplets in QCD
• Exotic Meson Production in the $f_1(1285){\pi }^{-}$ System observed in the Reaction ${\pi }^{-}p\to \eta {\pi }^{+}{\pi }^{-}{\pi }^{-}p$ at 18 GeV/c
• Radiative transitions of $D_{sJ}^{\ast }(2317)$ and $D_{sJ}(2460)$
• Observation of a Narrow Meson Decaying to Ds pi0 gamma at a Mass of 2.458 GeV/c^2
• One-pion-exchange final-state-interaction and the pbar p near threshold enhancement in J/psi -> gamma pbar p decays
• The DsJ(2317): what can the Lattice say?
• The spectrum of D_s mesons from lattice QCD
• A New State of Baryonium
• One Explanation for the Exotic State Y(4260)
• Study of the X(3872) and Y(4260) in B0-->J/psi pi+ pi- K0 and B-->J/psi pi+ pi- K- decays
• Experimental Search for Pentaquarks
• Possible Molecular Structure of the Newly Observed Y(4260)
• Charmonium's K2 peak
• First observation of a narrow charm-strange meson DsJ(2632) -> Ds eta and D0 K+
• Observation of a near-threshold enhancement in the ωϕmass spectrum from the doubly OZI suppressed decay J/ψ\to γωϕ
• Low-Mass Baryon-Antibaryon Enhancements in B Decays
• Exotic Meson Decay to $\omega {\pi }^0{\pi }^{-}$
• A chromomagnetic mechanism for the X(3872) resonance
• Strong coupling of excited heavy mesons
• Exclusive Production of the X(3872) in B Meson Decay
• Effects of S-wave thresholds
• Pionic Decays of $D_{sj}(2317)$, $D_{sj}(2460)$ and $B_{sj}(5718)$, $B_{sj}(5765)$
• D_{sJ}(2860) as the first radial excitation of the D_{s0}^*(2317)
• $D_{sJ}(2860)$ resonance and the $s_{\ell }^P={\frac{5}{2}}^{-}$ $c\bar{s}$ ($c\bar{q}$) doublet
• Evidence for Exotic J^{PC}=1^{-+} Meson Production in the Reaction pi- p --> eta pi- p at 18 GeV/c
• The Hidden Charm Decay of $X(3872),Y(3940)$ and Final State Interaction Effects
• Antibaryons bound in nuclei
• Open-charm meson spectroscopy
• Study of B -> DsJ(*)+ Dbar(*) Decays
• Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays
• Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks
• Model-independent view on the low-mass proton-antiproton enhancement
• Observation of Two New N* Peaks in J/psi -> $pp{i}^{-}\bar{n}$ and $\bar{p}{\pi }^{+}n$ Decays
• The Y(4260) as an omega chi_{c1} molecular state
• Y(4260) on the lattice
• Observation of a threshold enhancement in the p \bar{Lambda} invariant mass spectrum
• Determining the upper limit of Gamma_{ee} for the Y(4260)
• Comment on $D_s^{\ast }\to D_s{\pi }^0$ Decay
• Baryonium with a phenomenological skyrmion-type potential
• A search for J^{PC}=1^{-+} exotic mesons in the pi- pi- pi+ and pi- pi0 pi0 systems
• A partial wave analysis of the ${\pi }^{-}{\pi }^{-}{\pi }^{+}$ and ${\pi }^{-}{\pi }^0{\pi }^0$ systems and the search for a $J^{PC}=1^{-+}$ meson
• Some comments on narrow resonances D_{s_1}^* (2.46GeV/c^2) and D_{s0} (2.317GeV/c^2)
• Possible effects of color screening and large string tension in heavy quarkonium spectrum
• X(1835): A Natural Candidate of ${\eta }^{\prime }$'s Second Radial Excitation
• Theoretical Overview of the Pentaquark Baryons
• Strong decays of $D_{sJ}(2317)$ and $D_{sJ}(2460)$
• X(1835): A Possible Baryonium?
• Understanding the Possible Proton Antiproton Bound State Observed by BES Collaboration
• Observation of a broad 1^-- resonant structure around 1.5 GeV/$c^2$ in the K^+K^- mass spectrum in J/psi --> K^+K^-pi^0
• Qunatum Number Exotic Mesons and Large N QCD
• Duality in Left-Right Symmetric Seesaw Mechanism
• Gluonic excitation of non-exotic hybrid charmonium from lattice QCD
• Is $D_{sJ}^{+}(2632)$ the first radial excitation of $D_s^{\ast }(2112)$?
• Options for the SELEX state D$_{s\J}^+(2632)$
• Is the anomalous decay ratio of D_{sJ}(2632) due to isospin breaking?
• On possible $S$-wave bound states for a $N\bar{N}$ system within a constituent quark model
• Multichannel calculation for Ds* vector states and the Ds(2632) resonance
• $D_{sJ}^{+}(2632)$: An Excellent Candidate of Tetraquarks
• X(1812) in Quarkonia-Glueball-Hybrid Mixing Scheme
• A note on possible interpretations for the $D_{SJ}^{+}(2632)$ observed by SELEX
• The effect of $B\pi$ continuum in the QCD sum rules for the $(0^{+},1^{+})$ heavy meson doublet in HQET
• The masses and decay widths of heavy hybrid mesons
• On the near-threshold enhancement in $J/\psi \to \gamma X$ with $X\to \omega \varphi$
• D Wave Heavy Mesons
• Parity, Charge Conjugation and SU(3) Constraints on Threshold Enhancement in $J/\psi$ decays into $\gamma p\bar{p}$ and $Kp\bar{\Lambda }$
• Analysis of the X(1576) as a tetraquark state with the QCD sum rules
• The XYZs of Charmonium at BES
• Spectroscopy of ${\mathrm{q}}^3{\bar{\mathrm{q}}}^3$-States in Quark Model and Baryon-Antibaryon Enhancements
• Baryon Antibaryon Nonets
• X(1576) as Diquark-Antidiquark Bound State
• Subthreshold rho contribution in J/psi decay to omega pion pion and Kaon anti-Kaon pion
• Search for rare quark-annihilation decays, B --> Ds(*) Phi
• Isospin and a possible interpretation of the newly observed X(1576)
• Antiproton-proton resonant like channels in J/Psi decays into photon, proton and antiproton
• On tetraquark meson states

Cited by in corpus (98)

• The hidden-charm pentaquark and tetraquark states
• Non-Standard Heavy Mesons and Baryons, an Experimental Review
• Heavy-Quark QCD Exotica
• An updated review of the new hadron states
• The Physics of the B Factories
• A review of the open charm and open bottom systems
• New Charmonium States in QCD Sum Rules: a Concise Review
• The Exotic XYZ Charmonium-like Mesons
• Interactions of Charmed Mesons with Light Pseudoscalar Mesons from Lattice QCD and Implications on the Nature of the D_{s0}^*(2317)
• Is X(3872) {\sl Really} a Molecular State?
• The Y(3940), Z(3930) and the X(4160) as dynamically generated resonances from the vector-vector interaction
• The Vector and Axial-Vector Charmonium-like States
• Heavy-flavored tetraquark states with the $QQ\bar{Q}\bar{Q}$ configuration
• X(2175) as a resonant state of the $\varphi K\bar{K}$ system
• Weak decays of heavy hadrons into dynamically generated resonances
• ${\Lambda }_{c}N$ bound states revisited
• Y(4143) is probably a molecular partner of Y(3930)
• Radiative and isospin-violating decays of Ds mesons in the hadrogenesis conjecture
• QCD Sum Rules Approach to the $X,Y$ and $Z$ States
• Exotic $QQ\bar{q}\bar{q}$, $QQ\bar{q}\bar{s}$ and $QQ\bar{s}\bar{s}$ states
• Scattering lengths of Nambu-Goldstone bosons off $D$ mesons and dynamically generated heavy-light mesons
• Observation of the $\varphi (1680)$ and the Y(2175) in $e^{+}{e}^{-}\to \varphi {\pi }^{+}{\pi }^{-}$
• A New Hadron Spectroscopy
• D and D_s meson spectroscopy
• Y(4140): Possible options
• Light meson mass dependence of the positive parity heavy-strange mesons
• The Y(2175) State in the QCD Sum Rule
• Predicted charged charmonium-like structures in the hidden-charm dipion decay of higher charmonia
• Charm quark system at the physical point of 2+1 flavor lattice QCD
• Quark model description of the tetraquark state X(3872) in a relativistic constituent quark model with infrared confinement
• A fresh look into m_{c,b} and precise f_{D_(s),B_(s)} from heavy-light QCD spectral sum rules
• Study of J/psi->eta phi pi+pi- at BESIII
• 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 Spin-orbit force, recoil corrections and possible $B{\bar{B}}^{\ast }$ and $D{\bar{D}}^{\ast }$ molecular states
• Light Pseudoscalar Meson and Heavy Meson Scattering Lengths
• XYZ-like Spectra from Laplace Sum Rule at N2LO in the Chiral Limit
• Hidden-Charm Tetraquarks and Charged Zc States
• The meson-exchange model for the $\Lambda \bar{\Lambda }$ interaction
• Limits to the Fixed Center Approximation to Faddeev equations: the case of the $\varphi (2170)$
• Could $Z_c(3900)$ be a $I^G{J}^P=1^{+}{1}^{+}$ $D^{\ast }\bar{D}$ molecular state?
• Surveying exotic pentaquarks with the typical $QQqq\bar{q}$ configuration
• The bound state problem of S-wave heavy quark meson-aitimeson systems
• Hadronic molecules with both open charm and bottom
• Mass Spectrum of Heavy Quarkonium Hybrids
• Observation of a structure in $e^{+}{e}^{-}\to \varphi {\eta }^{\prime }$ at $\sqrt{s}$ from 2.05 to 3.08 GeV
• Spectroscopy behavior of fully heavy tetraquarks
• Width of exotics from QCD sum rules : tetraquarks or molecules?
• The $P$-wave $[cs][\bar{c}\bar{s}]$ tetraquark state: Y(4260) or Y(4660)?
• Triply heavy tetraquark states with the $QQ\bar{Q}\bar{q}$ configuration
• The I^G J^{PC}=0^+ 1^{-+} Tetraquark State
• X(3872) and the bound state problem of $D^0{\bar{D}}^{\ast 0}$ (${\bar{D}}^0{D}^{\ast 0}$) in a chiral quark model
• Stability of hexaquarks in the string limit of confinement
• Heavy Flavour Physics and CP Violation at LHCb: a Ten-Year Review
• Tetraquark interpolating fields in a lattice QCD investigation of the $D_{s0}^{\ast }(2317)$ meson
• Multichannel calculation of excited vector $\varphi$ resonances and the $\varphi (2170)$
• Possible $J^{PC}=0^{--}$ Charmonium-like State
• The Decay Properties of the 1^{-+} Hybrid State
• $D\bar{D}$ production and their interactions
• Masses of the tensor mesons with $J^P=2^{-}$
• Exotic B_c-like molecules in QCD Sum Rules
• Study of the process $e^{+}{e}^{-}\to \varphi \eta$ at center-of-mass energies between 2.00 and 3.08 GeV
• Baryonium Study in Heavy Baryon Chiral Perturbation Theory
• Could $Y_b(10890)$ be the P-wave $[bq][\bar{b}\bar{q}]$ tetraquark state?
• Using $X(3823)\to J/\psi {\pi }^{+}{\pi }^{-}$ to identify coupled-channel effects
• Y(4260) as a mixed charmonium-tetraquark state
• 1-- and 0++ heavy four-quark and molecule states in QCD
• Production of charm-strange hadronic molecules at the LHC
• Combined fit to BaBar and Belle Data on e+e- to phi pi+ pi- and phi f0(980)
• Meson-Hybrid Mixing in $J^{PC}=1^{++}$ Heavy Quarkonium from QCD Sum-Rules
• The phi(1020) a0(980) S-wave scattering and hints for a new vector-isovector resonance
• Discovery potential for charmonium-like state Y(3940) by the meson photoproduction
• Bound states on the lattice with partially twisted boundary conditions
• Predicting the existence of a 2.9 GeV $D{f}_0(980)$ molecular state
• Dynamical coupled-channel study of K* K*bar and omega phi states in a chiral quark model
• Exotic pentaquark states with the $qqQQ\bar{Q}$ configuration
• Semi-inclusive lepto-production of hidden-charm exotic hadrons
• Implications to $c\bar{s}$ assignments of $D_{s1}(2700{)}^{\pm }$ and $D_{sJ}(2860)$
• Weak Decays of Doubly-Heavy Tetraquarks $b\bar{c}q\bar{q}$
• The $X(2239)$ and $\eta (2225)$ as hidden-strange molecular states from $\Lambda \bar{\Lambda }$ interaction
• Analysis of the radiative decays among the charmonium states
• The "Closed" Chiral Symmetry and Its Application to Tetraquark
• Chiral Structure of Vector and Axial-Vector Tetraquark Currents
• The discrete contribution to ${\psi }^{\prime }\to J/\psi +\gamma \gamma$
• SU(3) analysis of fully-light tetraquarks in heavy meson weak decays
• S-wave DK interactions in the chiral SU(3) quark model
• Light-Cone Distribution Amplitudes of Light $J^{PC}=2^{--}$ Tensor Mesons in QCD
• Semileptonic decays of $B_{s1}$, $B_{s2}^{\ast }$, $B_{s0}$ and $B_{s1}^{\prime }$
• Chiral Structure of Scalar and Pseudoscalar Mesons
• Is there an isovector companion of the X(2175)?
• 1-- and 0++ Four-Quarks and Molecules from QCD Spectral Sum Rules
• Study of the hidden charm pentaquarks ${\Lambda }_{c\bar{c}}$ above $4$ GeV
• Study of $e^{+}{e}^{-}\to \eta \varphi$ via Initial State Radiation at Belle
• Dynamical study of the possible molecular state X(3872) with the s-channel one gluon exchange interaction
• Study the Heavy Molecular States in Quark Model with Meson Exchange Interaction
• ${\bar{D}}^0{D}^{0\ast }$ $(D^0{\bar{D}}^{0\ast })$ System in QCD-Improved Many Body Potential
• X, Y and Z States
• Chiral corrections to the $1^{-+}$ exotic meson mass
• Hadron resonances generated from the dynamics of the lightest scalar ones