$QQ\bar{s}\bar{s}$ tetraquarks in the chiral quark model

Abstract

The low-lying $S$-wave $QQ\bar{s}\bar{s}$ ($Q=c,b$) tetraquark states with $I{J}^P=00^{+}$, $01^{+}$ and $02^{+}$ are systematically investigated in the framework of complex scaling range of chiral quark model. Every structure including meson-meson, diquark-antidiquark and K-type configurations, and all possible color channels in four-body sector are considered by means of a commonly extended variational approach, Gaussian expansion method. Several narrow and wide resonance states are obtained for $cc\bar{s}\bar{s}$ and $bb\bar{s}\bar{s}$ tetraquarks with $I{J}^P=00^{+}$ and $02^{+}$. Meanwhile, narrow resonances for $cb\bar{s}\bar{s}$ tetraquarks are also found in $I{J}^P=00^{+}$, $01^{+}$ and $02^{+}$ states. These results confirm the possibility of finding hadronic molecules with masses $\sim 0.6\text{GeV}$ above the noninteracting hadron-hadron thresholds.

Comments: 18 pages, 19 tables and 10 figures