Pentaquarks in the Jaffe-Wilczek Approximation

The masses of $uuddbar s $, $uuddbar d$ and $uussbar d$ pentaquarks are evaluated in a framework of both the Effective Hamiltonian approach to QCD and spinless Salpeter using the Jaffe--Wilczek diquark approximation and the string interaction for the diquark--diquark--antiquark system. The pentaquark masses are found to be in the region above 2 GeV. That indicates that the Goldstone boson exchange effects may play an important role in the light pentaquarks. The same calculations yield the mass of $[ud]^2bar c$ pentaquark $sim$ 3250 MeV and $[ud]^2bar b$ pentaquark $sim$ 6509 MeV.