Analysis of the hidden-charm-hidden-strange tetraquark mass spectrum via the QCD sum rules

Abstract

In the present work, we construct the diquark-antidiquark type four-quark currents to investigate the mass spectrum of the ground state hidden-charm-hidden-strange tetraquark states with the quantum numbers $J^{PC}=0^{++}$, $1^{+-}$, $1^{++}$ and $2^{++}$ via the traditional QCD sum rules in a comprehensive way. We update old calculations, perform new calculations and analysis in a rigorous way, and take account of the net light-flavor $SU(3)$ breaking effects in a consistent way. And we make more reasonable identifications for the $X(3960)$, $X(4140)$, $X(4274)$, $X(4500)$, $X(4685)$ and $X(4700)$ and supersede some old identifications. Furthermore, we consider our previous theoretical predictions, and make reasonable/suitable identifications of the new LHCb states $h_c(4000)$ and $\chi_{c1}(4010)$.