Narrow-width tetraquarks in large-$N_{\mathrm{c}}^{}$ QCD

TL;DR

This paper investigates the theoretical possibility of narrow-width tetraquarks within large-$N_c$ QCD, emphasizing the importance of analyzing Feynman diagram singularities to identify potential tetraquark contributions.

Contribution

It introduces a detailed analysis of Feynman diagram singularities using Landau equations to assess tetraquark formation in large-$N_c$ QCD.

Findings

Tetraquarks, if they exist, are predicted to have narrow widths of order $N_c^{-2}$.

The study highlights the necessity of analyzing diagram singularities to identify tetraquark contributions.

Abstract

The properties of possibly existing tetraquarks are studied in the large-$N_{\mathrm{c}}^{}$ limit of QCD by means of four-point correlation functions of meson currents.The necessity of a detailed analysis of the singularities of Feynman diagrams, by means of the Landau equations, to recognize those diagrams that might contribute to the formation of tetraquark states, is emphasized. It is found, in general, that tetraquarks, if they exist, should have narrow widths of the order of $N_{\mathrm{c}}^{-2}$.