Enhanced non-quark-antiquark and non-glueball Nc behavior of light scalar mesons

Abstract

We show that the latest and very precise dispersive data analyses require a large and very unnat- ural fine-tuning of the 1/Nc expansion at Nc = 3 if the f_0(600) and K(800) light scalar mesons are to be considered predominantly quark-antiquark states, which is not needed for light vector mesons. For this, we use scattering observables whose 1/Nc corrections are suppressed further than one power of 1/Nc for quark-antiquark or glueball states, thus enhancing contributions of other nature. This is achieved without using unitarized ChPT, but if it is used we can also show that it is not just that the coefficients of the 1/Nc expansion are unnatural, but that the expansion itself does not even follow the expected 1/Nc scaling of a glueball or a quark-antiquark meson.

Discussion disfavoring a glueball interpretation added. Version published in Phys. Rev. D

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• Ordinary and Extraordinary Hadrons
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• Chiral extrapolation of pion-pion scattering phase shifts within standard and unitarized Chiral Perturbation Theory
• Nature of the sigma meson as revealed by its softening process
• Meson Resonances at large Nc: Complex Poles vs Breit-Wigner Masses
• Light scalar tetraquarks from a holographic perspective
• Fock space expansion of sigma meson in leading-Nc

Cited by in corpus (15)

• Hadronic molecules
• From controversy to precision on the sigma meson: a review on the status of the non-ordinary $f_0(500)$ resonance
• 50 Years of Quantum Chromodynamics
• Structure and compositeness of hadron resonances
• Systematics of radial and angular-momentum Regge trajectories of light non-strange q\bar{q}-states
• Large-Nc Properties of the rho and f0(600) Mesons from Unitary Resonance Chiral Dynamics
• Non-ordinary light meson couplings and the $1/N_c$ expansion
• Four-quark states from functional methods
• Holography Inspired Stringy Hadrons
• The Large $N_c$ limit of QCD on the lattice
• Glueballs as rotating folded closed strings
• Bound states on the lattice with partially twisted boundary conditions
• $N_C$ evolution of the light meson resonances
• Lifetime of the eta' meson at low temperature
• Precision dispersive approaches versus unitarized Chiral Perturbation Theory for the lightest scalar resonances $\sigma /f_0(500)$ and $\kappa /K_0^{\ast }(700)$