Quark Confinement for Multi-Quark Systems -- Application to Fully-Charmed Tetraquarks

Abstract

A new color basis system and confinement mechanism for multi-quark 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 $QQ\bar{Q}\bar{Q}$ systems includes a ''hidden color'' state, which mixes with two-meson states $Q\bar{Q}+Q\bar{Q}$, This mixing effect leads to an attractive potential sufficient to form a bound state. We apply a realistic Hamiltonian model with the new scheme to fully charmed tetraquark states, $cc\bar{c}\bar{c}$, and find a bound and two resonant states, which could potentially correspond to the $cc\bar{c}\bar{c}$ tetraquark candidates recently observed in experiments.

Comments: 6 pages, 3 figures