Stable uudd \bar s pentaquarks in the constituent quark model

The stability of strange pentaquarks uudd (s) over bar is studied in a constituent quark model based on a flavor-spin hyperfine interaction between quarks. With this interaction model, which schematically represents the Goldstone boson exchange interaction between constituent quarks, the lowest lying strange pentaquark is a p-shell state with positive parity. The flavor-spin interaction lowers the energy of the lowest p-shell state below that of the lowest s-shell state, which has negative parity because of the negative parity of the strange antiquark. It is found that the strange pentaquark can be stable against strong decay provided that the strange antiquark interacts by a fairly strong spin-spin interaction with u and d quarks. This interaction has a form that corresponds to, eta meson exchange. Its strength may be inferred from the pi(0) decay width of D*(s) mesons. (C) 2003 Elsevier B.V. All rights reserved.