Non-ordinary light meson couplings and the $1/N_c$ expansion

Abstract

We study the large $N_c$ behavior of couplings among light meson states with different compositions in terms of quarks and gluons. We shortly review the most common compositions of mesons, which are of interest for the understanding of low-lying meson resonances, namely, the ordinary quark-antiquark states as well as the non-ordinary, glueball, tetraquark, etc. We dedicate special attention to Jaffe's generalization of the tetraquark with $N_c-1$ $q\bar{q}$ pairs, that is the only type of state we have identified, whose width does not necessarily vanish with $N_c$, while it does decouple exponentially with $N_c$ from the $\pi \pi$ channel, so that is weakly coupled to the meson-meson system.

37 pages and 12 figures

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Cited by in corpus (11)

• Multiquark Resonances
• Remarks on pole trajectories for resonances
• Large-$N_c$ naturalness in coupled-channel meson-meson scattering
• Interpretation of $Y_b(10750)$ as a tetraquark and its production mechanism
• Tetraquark and two-meson states at large $N_{\mathrm{c}}$
• Feynman-Hellmann theorem for resonances and the quest for QCD exotica
• Analysis on the composite nature of the light scalar mesons $f_0(980)$ and $a_0(980)$
• OPE and quark-hadron duality for two-point functions of tetraquark currents in $1/N_c$ expansion
• Observation of $D^{+}\to f_0(500){\mu }^{+}{\nu }_{\mu }$ and study of $D^{+}\to {\pi }^{+}{\pi }^{-}{\ell }^{+}{\nu }_{\ell }$ decay dynamics
• Dynamical origin of neutrino masses and dark matter from a new confining sector
• $N_C$ evolution of the light meson resonances