Investigation of tetraquark in the chiral quark model
Yifan Yang (Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems, Nanjing Normal University, Nanjing 210023, People’s Republic of China); Jialun Ping (Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems, Nanjing Normal University, Nanjing 210023, People’s Republic of China)
Inspired by the recent observation of exotic resonances , , , , and reported by several experiment collaborations, we investigated the four-quark system with quantum numbers and 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 . In the present calculation, the can be assigned as the tetraquark states with , but the energy of is too low to be regarded as the tetraquark state. can be a good candidate of the compact tetraquark state with . When the radial excitation is taken into account, the can be explained as the radial excited tetraquark state with . As for , there is no matching state in our calculation.