Exotic states and their properties from large-n<sub>c</sub> qcd

Author(s): Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian
Abstract: The analysis of two-ordinary-meson scattering amplitudes in the limit of a large number, N_c, of the colour degrees of freedom of quantum chromodynamics, with suitably decreasing strong coupling and all quarks transforming according to the gauge group’s fundamental representation, enables us to establish a set of rigorous consistency conditions for the emergence of a tetraquark (i.e., a bound state of two quarks and two antiquarks) as a pole in these amplitudes. For genuinely flavour-exotic tetraquarks, these constraints require the existence of two tetraquark states distinguishable by their preferred couplings to two ordinary mesons, whereas, for cryptoexotic tetraquarks, our constraints may be satisfied by a single tetraquark state, which then, however, may mix with ordinary mesons. For elucidation of the tetraquark features, the consideration of the subleading contributions proves to be mandatory: For both variants of tetraquarks, their decay widths fall off like 1/N_c ² for large N_c
Organisation(s): Particle Physics
External organisation(s): Österreichische Akademie der Wissenschaften (ÖAW), Anuchin Research Institute and Museum of Anthropology, Universität Wien, Centre National De La Recherche Scientifique (CNRS)
Journal: Proceedings of Science (PoS)
Volume: 314
No. of pages: 4
DOI: https://doi.org/10.22323/1.314.0390
Publication date: 2018
Peer reviewed: Yes
Austrian Fields of Science 2012: 103034 Particle physics
ASJC Scopus subject areas: General
Portal url: https://ucris.univie.ac.at/portal/en/publications/exotic-states-and-their-properties-from-largenc-qcd(0d65f0c6-9224-4e9e-88c1-c01819dfbb94).html