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

The Theta+(1540), recently observed at LEPS, DIANA and CLAS, is hypothesized to be an isotensor resonance. This implies the existence of a multiplet where the Theta++, Theta+ and Theta0 have isospin-violating strong decays, and the Theta+++ and Theta- have weak decays and so are long-lived. Production mechanisms for these states are discussed. The J^P assignment of the Theta is most likely 1/2^- or 3/2^-.