Lattice QCD study of four-quark components of the isosinglet scalar mesons: Significance of disconnected diagrams

Abstract

We study the possible significance of four-quark states in the iso-singlet scalar mesons ($J^{PC}=0^{++}$, $I=0$) by performing two-flavor full lattice QCD simulations on an $8^3\times 16$ lattice using the improved gauge action and the clover-improved Wilson quark action. In particular, we evaluate the propagators of molecular and tetra-quark operators together with singly disconnected diagrams. In the computation of the singly disconnected diagrams we employ the $Z_2$-noise method with the truncated eigenmode approach. We show that the quark loops given by the disconnected diagrams play an essential role in propagators of tetraquark and molecular operators.

18 pages, 7 figures

References in corpus (8)

• Observation of a resonance-like structure in the pi^+- psi' mass distribution in exclusive B-->K pi^+- psi' decays
• Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle
• Evidence for diquarks in lattice QCD
• Scalar Mesons a0(1450) and sigma(600) from Lattice QCD
• Lattice study of light scalar tetraquarks with I=0,2,1/2,3/2: are sigma and kappa tetraquarks?
• A lattice study of the masses of singlet 0++ mesons
• Tetra-Quark Resonances in Lattice QCD
• Lowest-lying Tetra-Quark Hadrons in Anisotropic Lattice QCD

Cited by in corpus (10)

• 50 Years of Quantum Chromodynamics
• Isoscalar $\pi \pi$ scattering and the $\sigma$ meson resonance from QCD
• Emergent Hadrons and Diquarks
• Hadronic three-body D decays mediated by scalar resonances
• Novel pentaquark picture for singly heavy baryons from chiral symmetry
• The light scalars: four- vs. two-quark states in the complex energy plane from Bethe-Salpeter equations
• The sigma meson from QCD sum rules for large-$N_c$ Regge spectra
• Observation of $D^{+}\to f_0(500){\mu }^{+}{\nu }_{\mu }$ and study of $D^{+}\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decay dynamics
• Importance of closed quark loops for lattice QCD studies of tetraquarks
• Precision dispersive approaches versus unitarized Chiral Perturbation Theory for the lightest scalar resonances $\sigma /f_0(500)$ and $\kappa /K_0^{\ast }(700)$