Four-quark states in heavy quark systems

Abstract

Heavy four-quark states R4q = qqq are considered in the framework of potential models. Special attention is paid to the possibility of observing such states in e+e− annihilation. It is shown that in the cccc system there must exist a resonance with JPC = 1−−, spin S = 2, with mass M ≈ 6.75 GeV, Γe+e−∼0.02 eV and a total width of Γtot∼10 MeV. For analogous states in the cscs andssss systems we have obtained Mcscs ≈4.8 GeV, Γe+e−∼0.4 eV and Mssss≈2.7 GeV, Γe+e−∼3 eV. The decay modes of such states and possibilities of their detection are discussed. The masses of C-even 4-quark states are also calculated and their 2γ decay widths and the probabilities for charmonium and upsilonium radiative decays to these states are estimated.