The narrow pentaquark

The experimental status of the pentaquark searches is briefly reviewed. Recent null results by the CLAS collaboration are commented, and new strong evidence of a very narrow Theta(+) resonance by the DIANA collaboration is presented. On the theory side, I revisit the argument against the existence of the pentaquark - that of Callan and Klebanov - and show that actually a strong resonance is predicted in that approach, however its width is grossly overestimated. A recent calculation gives 2 MeV for the pentaquark width, and this number is probably still an upper bound [1].