Pentaquarks in the Jaffe-Wilczek approximation

The masses of $uudd\bar{s}$, $uudd\bar{d}$ and $uuss\bar{d}$ 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 $[ud{]}^2\bar{c}$ pentaquark $\sim$ 3250 MeV and $[ud{]}^2\bar{b}$ pentaquark $\sim$ 6509 MeV.