Cohen, ThomasLlanes Estrada, Felipe JoséPeláez Sagredo, José RamónRuiz De Elvira Carrascal, Jacobo2023-06-192023-06-192014-08-140556-282110.1103/PhysRevD.90.036003https://hdl.handle.net/20.500.14352/33905© 2014 American Physical Society. This work was partially supported by the Spanish Research Contracts No. FIS2008-01323, No. FPA2011-27853-C02-01, and No. FPA2011-27853-C02-02 and the DFG (No. SFB/TR 16, “Subnuclear Structure of Matter”). We acknowledge the support of the European Community-Research Infrastructure Integrating Activity “Study of Strongly Interacting Matter” (HadronPhysics2), Grant Agreement No. 227431 under the Seventh Framework Programme of the EU.We study the large Nc 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 nonordinary glueball, tetraquark, and other states. We dedicate special attention to Jaffe’s generalization of the tetraquark with Nc − 1 q¯q pairs, which is the only type of state we have identified whose width does not necessarily vanish with Nc, though it does decouple exponentially with Nc from the ππ channel, so that it is weakly coupled to the meson-meson system.engNonordinary light meson couplings and the 1/Nc expansionjournal articlehttp://dx.doi.org/10.1103/PhysRevD.90.036003http://journals.aps.org/open access51-7353Chiral pertubation-theoryLarge N-CExtraordinary hadrons1-N expansionResonancesBaryonsQuark.Física-Modelos matemáticos