Interpretation of the Θ+ as an isotensor pentaquark with weakly decaying partners

The Θ+(1540), recently observed at LEPS, DIANA and CLAS, is hypothesized to be an isotensor resonance. This implies the existence of a multiplet where the Θ++, Θ+ and Θ0 have isospin-violating strong decays, and the Θ+++ and Θ− have weak decays and so are long-lived. Production mechanisms for the weakly-decaying states are discussed. The JP assignment of the Θ is most likely 1/2− or 3/2−.