Exotic mesons with hidden charm as diquark-antidiquark states

Exotic mesons with hidden strange (s (s) over bar) and heavy quark pairs (Q (Q) over bar), where Q = c, b, are considered as diquark-antidiquark systems, (Qs) . ((Q) over bar(s) over bar). Taking into account that these states can recombinate into two-meson ones, we study the interplay of these states in terms of the dispersion relation D-function technique. The classification of exotic mesons is discussed, coefficients for decay modes are given, predictions for new states are presented. The nonet structure for (Qq) . ((Q) over bar(q) over bar), (Qs) . ((Q) over bar(s) over bar), (Qq) . ((Q) over bar(s) over bar)-states (q = u, d) is suggested.