Compact Exotic Tetraquark Mesons in Large-NcQCD

Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian, V.E. Volkova, Y.V. Zhezher, D.G. Levkov, V.A. Rubakov, V.A. Matveev
2018 EPJ Web of Conferences  
We embark on systematic explorations of the behaviour of tetraquark mesons, i.e., colour-singlet bound states of two quarks and two antiquarks, in the (idealized) limit of a large number of colour degrees of freedom, N c , of quantum chromodynamics, QCD. Considering the scattering of two ordinary mesons into two ordinary mesons, we start off with formulating a set of selection criteria that should enable us to unambiguously single out precisely those contributions to all encountered scattering
more » ... mplitudes that potentially will develop tetraquark poles. Assuming that tetraquark mesons do exist and, if so, emerge in the contributions compatible with our criteria at largest admissible order of N c , we deduce, for the categories of tetraquarks that exhibit either four or only two different open quark flavours, that the decay rates of these tetraquark types are, at least, of order 1/N 2 c and that internal consistency requires all the members of the first species to exist pairwise, distinguishable by their favoured two-ordinary-meson decay channels. *
doi:10.1051/epjconf/201819104003 fatcat:bustqzkkgrdqfbmwl7utc4aznu