Quark confinement for multiquark systems: Application to fully charmed tetraquarks

A new color basis system and confinement mechanism for multiquark systems are proposed according to the string-type picture of QCD. The color string configurations in the strong coupling QCD are implemented in the set of color basis states. The extended color Hilbert space for QQQ over bar Q over bar systems includes a "hidden color" state, which mixes with two-meson states Q sufficient to form a bound state. We apply a realistic Hamiltonian model with the new scheme to fully charmed tetraquark states, ccc over bar c over bar , and find a bound and two resonant states, which could potentially correspond to the ccc over bar c over bar tetraquark candidates recently observed in experiments. Q thorn Q Q over bar , This mixing effect leads to an attractive potential