Investigation of cs(c)over-bar (s)over-bar tetraquark in the chiral quark model

Inspired by the recent observation of exotic resonances X(4140), X(4274), X(4350), X(4500), and X(4700) reported by several experiment collaborations, we investigated the four-quark system cs (c) over tilde (s) over bar with quantum numbers J(PC) = 1(++) and 0(++) in the framework of the chiral quark model. Two configurations, diquark-antidiquark and meson-meson, with all possible color structures are considered. The results show that no molecular state can be formed, but the resonance may exist if the color structure of the meson-meson configuration is 8 circle times 8. In the present calculation, the X(4274) can be assigned as the cs (c) over bar (s) over bar tetraquark states with J(PC) = 1(++), but the energy of X(4140) is too low to be regarded as the tetraquark state. X(4350) can be a good candidate of the compact tetraquark state with J(PC) = 0(++). When the radial excitation is taken into account, the X(4700) can be explained as the 2S radial excited tetraquark state with J(PC) = 0(++). As for X(4500), there is no matching state in our calculation.