Diquark and light four-quark states

Abstract

Four-quark states with different internal clusters are discussed within the constituent quark model. It is pointed out that the diquark concept is not meaningful in the construction of a tetraquark interpolating current in the QCD sum rule approach, and hence existing sum-rule studies of four-quark states are incomplete. An updated QCD sum-rule determination of the properties of diquark clusters is then used as input for the constituent quark model to obtain the masses of light $0^{++}$ tetraquark states ({\it i.e.\} a bound state of two diquark clusters). The results support the identification of $\sigma (600)$, $f_0(980)$ and $a_0(980)$ as the $0^{++}$ light tetraquark states, and seem to be inconsistent with the tetraquark state interpretation of the new BES observations of the near-threshold $p\bar{p}$ enhancements, X(1835) and X(1812), with the possible exception that X(1576) may be an "exotic" first orbital excitation of $f_0(980)$ or $a_0(980)$.

7 pages, 4 eps figures, RevTex, two figures and some references added, published version in PRD

References in corpus (47)

• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• The Cosmological Parameters 2006
• Observation of a narrow charmonium-like state in exclusive B+ -> K+ pi+pi- J/psi decays
• Observation of a New Narrow Charmonium State in Exclusive B+-->K+ pi+pi- J/psi Decays
• Diquark-Antidiquarks with Hidden or Open Charm and the Nature of X(3872)
• Diquarks and Exotic Spectroscopy
• Chiral Symmetry Amplitudes in the S-Wave Isoscalar and Isovector Channels and the σ, f_0(980), a_0(980) Scalar Mesons
• Chiral symmetry amplitudes in the s-wave isoscalar and isovector channels and the $\sigma ,f_0(980),a_0(980)$ scalar mesons
• Observation of a Broad Structure in the ${\pi }^{+}{\pi }^{-}J/\psi$ Mass Spectrum around 4.26 GeV/$c^2$
• QCD forces and heavy quark bound states
• The Spectrum of the Nucleons and the Strange Hyperons and Chiral Dynamics
• Exotica
• Isospin breaking of the narrow charmonium state of Belle at 3872 MeV as a deuson
• Short Range Structure in the X(3872)
• QCD at Low Energies
• A new look at scalar mesons
• Scalar mesons above and below 1 GeV
• 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
• A low-lying scalar meson nonet in a unitarized meson model
• On the nature of light scalar mesons from their large $N_c$ behavior
• Interference and binding effects in decays of possible molecular component of X(3872)
• A Diquark-Triquark Model for the KN Pentaquark
• Putative Light Scalar Nonet
• Molecular States of Heavy Quark Mesons
• Four Quark Interpretation of Y(4260)
• Masses of heavy tetraquarks in the relativistic quark model
• Nature of the f_0(600) from its N_c dependence at two loops in unitarized Chiral Perturbation Theory
• Observation of a resonance X(1835) in J/ψ--> γπ^+ π^- η^{\prime}
• A schematic model for pentaquarks based on diquarks
• Observation of a near-threshold enhancement in the ωϕmass spectrum from the doubly OZI suppressed decay J/ψ\to γωϕ
• Disentangling two- and four-quark state pictures of the charmed scalar mesons
• Study of the Baryon-Antibaryon Low-Mass Enhancements in Charmless Three-body Baryonic B Decays
• D_s (2317) as a four-quark state in QCD sum rules
• A Relativistic Quark Model for Mesons with an Instanton-Induced Interaction
• Exotic Tetraquark ud bar[s] bar[s] of J^P=0^+ in the QCD Sum Rule
• Search for isotensor exotic meson and twist 4 contribution to ${\gamma }^{\ast }\gamma \to \rho \rho$
• 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
• History of exotic Meson (4-quark) and Baryon (5-quark) States
• Four-quark state in QCD
• Strange Quark, Tachyonic Gluon Masses and V_{us} from Hadronic Tau Decays
• Production of a Q^2\bar{Q}^2 state in J/ψ\to γωϕ
• Correspondence between QCD sum rules and constituent quark models
• X(1576) as Diquark-Antidiquark Bound State
• Instantons and Scalar Multiquark States: From Small to Large N_c
• Isospin and a possible interpretation of the newly observed X(1576)
• Four-Quark Mesons

Cited by in corpus (31)

• Pentaquark and Tetraquark states
• Analysis of the X(3872), Z_c(3900) and Z_c(3885) as axial-vector tetraquark states with QCD sum rules
• Heavy-light diquark masses from QCD sum rules and constituent diquark models of tetraquarks
• On the size of the sigma meson and its nature
• Light Scalar Tetraquark Mesons in the QCD Sum Rule
• The Y(2175) State in the QCD Sum Rule
• Analysis of the scalar and axial-vector heavy diquark states with QCD sum rules
• Exotic open-flavor $bc\bar{q}\bar{q}$, $bc\bar{s}\bar{s}$ and $qc\bar{q}\bar{b}$, $sc\bar{s}\bar{b}$ tetraquark states
• QCD Sum-Rule Interpretation of X(3872) with $J^{PC}=1^{++}$ Mixtures of Hybrid Charmonium and $\bar{D}{D}^{\ast }$ Molecular Currents
• Two chiral nonet model with massless quarks
• Analysis of the light-flavor scalar and axial-vector diquark states with QCD sum rules
• Do the QCD sum rules support four-quark states?
• $J^P$ Assignments of ${\Lambda }_c^{+}$ Baryons
• Theoretical support for the $\pi (1300)$ and the recently claimed $f_0(1790)$ as molecular resonances
• QCD sum rule studies on the $ss\bar{s}\bar{s}$ tetraquark states with $J^{PC}=1^{+-}$
• Fully open-flavor tetraquark states $bc\bar{q}\bar{s}$ and $sc\bar{q}\bar{b}$ with $J^P=0^{+},1^{+}$
• Axial Vector $cc$ and $bb$ Diquark Masses from QCD Laplace Sum-Rules
• Dynamical coupled-channel study of K* K*bar and omega phi states in a chiral quark model
• New molecular candidates: X(1910), X(2200), and X(2350)
• Analysis of the nonet scalar mesons as tetraquark states with new QCD sum rules
• Inverse Mass Hierarchy of Light Scalar Mesons Driven by Anomaly-Induced Flavor Breaking
• Regge trajectory relations for the universal description of the heavy-light systems: diquarks, mesons, baryons and tetraquarks
• Masses of doubly heavy tetraquarks $QQ\bar{n}\bar{q}$ with $J^P=1^{+}$
• Search for $Z_{s1}^{+}$ and $Z_{s2}^{+}$ strangeonium-like structures
• Discussions on Stability of Diquarks
• A possible explanation of a broad $1^{--}$ resonant structure around 1.5GeV
• Two-Loop QCD Renormalization and Anomalous Dimension of the Scalar Diquark Operator
• Revisiting light-flavor diquarks in the inverse matrix method of QCD sum rules
• Non-perturbative Analysis of Various Mass Generation by Gluonic Dressing Effect with the Schwinger-Dyson Formalism in QCD
• Analysis of the tensor-tensor type scalar tetraquark states with QCD sum rules
• Isospin breaking from diquark clustering