Hidden and double charm-strange tetraquarks and their decays in a potential quark model

We carry out a systematic study of the $1S$-wave hidden and double charm-strange tetraquarks csc̄s̄ and ccs̄s̄ in a nonrelativistic potential quark model framework with the explicitly correlated Gaussian method, and the mass spectra, color-spin configurations and possible decay modes are obtained. We find that although these states are all above their open flavor thresholds, their rearrangement decay widths are rather narrow which can be understood by the mismatching of the wave functions between the initial and final states. It implies that the tetraquarks of csc̄s̄ and ccs̄s̄ may have a good chance to exist as genuine tetraquark states. It also shows that the color-spin configurations of the csc̄s̄ and ccs̄s̄ systems are quite different. We find that for a physical state of csc̄s̄ its color configurations can be dominated by either the |11c or |88c ones. It suggests that some hidden charm-strange tetraquark states may strongly couple to two color-singlet hadrons if the kinematics and dynamics allow. In contrast, we find that the color configurations |11c and |88c in a double charm-strange ccs̄s̄ state are rather compatible. It may suggest that an overall color-singlet tetraquark (i.e. a genuine color-singlet) should always play a role in the Tccs̄s̄ states. Discussions taking into account some experimental candidates are presented, and suggestions on further experimental searches are also made.