Instantons and Scalar Multiquark States: From Small to Large N_c

Abstract

We study scalar quark-anti-quark and two-quark-two-anti-quark correlation functions in the instanton liquid model. We show that the instanton liquid supports a light scalar-isoscalar (sigma) meson, and that this state is strongly coupled to both $(\bar{q}q)$ and $(\bar{q}q{)}^2$. The scalar-isovector $a_0$ meson, on the other hand, is heavy. We also show that these properties are specific to QCD with three colors. In the large $N_c$ limit the scalar-isoscalar meson is not light, and it is mainly coupled to $(\bar{q}q)$.

24 pages

References in corpus (3)

• Evidence for Instanton-Induced Dynamics, from Lattice QCD
• QCD based quark description of pi-pi scattering up to the sigma and rho region
• Quenched scalar meson correlator with Domain Wall Fermions

Cited by in corpus (11)

• Tetraquark spectroscopy
• Diquark and light four-quark states
• Lattice Study of Low-lying Nonet Scalar Mesons in Quenched Approximation
• Instanton interpolating current for $\sigma$--tetraquark
• Nature of the sigma meson as revealed by its softening process
• Light Scalar Mesons in the Improved Ladder QCD
• Light scalar tetraquarks from a holographic perspective
• QCD sum rules at finite density in the large-N_c limit: The coupling of the rho-nucleon system to the D_{13}(1520)
• The low-lying Scalar Mesons and Related Topics
• Chiral Structure of Scalar and Pseudoscalar Mesons
• Understanding light scalar meson by color-magnetic wavefunction in QCD sum rule