The isotensor pentaquark

Abstract

Further consequences of the 1540 MeV Theta+ resonance as an isotensor pentaquark beyond Capstick et al. are explored. It is argued that the SAPHIR data may not currently exclude the existence of the charged partner Theta++. The usual prediction of the dominance of non-resonant Theta+ K, and Theta+ K*, final states in photoproduction on the proton is argued not to obtain for an isotensor Theta+. This enhances the importance of excited baryon final states, where the excited baryon decays to Theta+ K or Theta+ K*; as well as the non-resonant Theta+ K pi final state. The small width of the recently discovered Xi-- cascade resonance to Xi- pi- is easier to explain if Theta+ is an isotensor pentaquark than if it is in the 10bar representation, due to both an isospin and U-spin selection rule. A new production diagram for Theta+ in the photoproduction on the deuteron is suggested.