Investigation of qqqs(q)over-bar pentaquarks in a chiral quark model

We investigate the pentaquark system qqqs (q) over bar in a framework of chiral quark model. Two structures, (qqq)(s (q) over bar) and (qqs)(q (q) over bar), with all possible color, spin, flavor configurations are considered. The calculations show that there are several possible resonance states, Sigma pi and N (K) over bar state with IJ(P )= 0 1(-)/2, Sigma*pi with IJ(P) = 0 3(-)/2, Sigma*rho with IJ(P )= 0 5(-)/2, Delta(K) over bar with IJ(P) = 1 3(-)/2, and Delta(K) over bar* with IJ(P )= 1 5(-)/2. Where the N (K) over bar state with IJ(P )= 0 1(-)/2 can be used to explain the Lambda(1405), and together with another state Sigma pi is related to the two-pole structure of the scattering amplitude proposed before. The decay properties of Lambda(1520) prevent the assignment of Sigma*pi with IJ(P) = 0 3(-)/2 to Lambda(1520), although the energy approximate to 1518MeV of Sigma*pi is close to experimental value of Lambda(1520). Other resonance states generally have a large width.

Automated summary

In this study, the pentaquark system qqqs (q) over bar is investigated within the framework of chiral quark model. Various resonance states with different quantum numbers are predicted, and some states are proposed to explain specific particles. However, most resonance states generally exhibit a large width.