Why pentaquarks are seen in some experiments and not in others

Abstract

The ${\Theta }^{+}$ Pentaquark is a Very narrow $\Gamma \approx 1$ MeV KN Resonance. Why do some experiments see it and others do not? The lowest quark configuration that can describe it is exotic $uudd\bar{s}$. Why have no exotics been seen before? Is this the beginning of a new spectroscopy? Can it help toteach us about How QCD makes hadrons from quarks and gluons?

Comments: 4 pages