手征夸克模型下udss四夸克态的研究.pdf

1 31 ò 1 9 ? 2007 c 9 ? p U ? n ? ? ? n HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS Vol. 31, No. 9 Sep., 2007 Chiral Quark Model Study of udˉsˉs Tetraquark States * ZHANG Zong-Ye 1 WANG Wen-Ling 2;1) HUANG Fei 3 YU You-Wen 1 LIU Feng 2 1 (Institute of High Energy Physics, CAS, Beijing 100049, China ) 2 (Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, China) 3 (CCAST (World Laboratory), Beijing 100080, China) Abstract The energies of the low-lying isoscalar and isovector udˉsˉs con?gurations 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 ?xed by the masses of K and K ?mesons, and the con?guration mixing is considered. The results show that the udˉsˉs con?guration 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. Key words tetraquark state, quark model, chiral symmetry 1 Introduction Since Ja?e predicted the H particle (uuddss) in 1977 [1], the research on multi-quark s