CAS, Inst High Energy Phys, Beijing 100049, Peoples R China
; Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China
; CCAST, World Lab, Beijing 100080, Peoples R China
The energies of the low-lying isoscalar and isovector ud (s) over bar(s) over bar configurations with spin-parity J(P) = 0(+), 1(+), and 2(+) are calculated in the chiral SU(3) quark model and the extended chiral SU(3) quark model by using the variational method. The model parameters are determined by the same method as in our previous work, and they still can satisfactorily describes the nucleon-nucleon scattering phase shifts and the hyperon-nucleon cross sections. The s-channel annihilation interaction is fixed by the masses of K and K* mesons, and the configuration mixing is considered. The results show that the ud (s) over bar(s) over bar configuration with I = 0 and J(P) = 1(+) lies lower than the K*K* threshold, and furthermore, this state has a very small KK* component, thus it can be treated as a possible tetraquark candidate.