Understanding penta quark with various quark models

Abstract

The pentaquark state recently discovered has been studied with three quark models which either fit the nucleon spin structure or the $NN$ scattering. A minimum ${\Theta }^{+}$ mass of 1620 MeV is obtained both for the ${1/2}^{\pm }$ state. The mixing of various color structure configurations, which would reduce the mass of the penta-quark state, should be taking into account in the calculation of penta-quark mass.

Comments: 14 pages, 7 figures