Stable heavy pentaquark states

If the Θ+(1540) is interpreted as a bound state of a s-bar quark and two (ud) diquarks in a relative P-wave, then it is very likely that there exist pentaquark states with a heavy antiquark, b-bar or c-bar, and two 'light' diquarks in a relative S-wave which are stable against strong decays. We make a mass estimate for exotic states of this type and discuss their weak decays. Isospin relations are constructed which test their flavor quantum numbers