Improved study of a possible Θ+ production in the p p → p K0 Σ+ reaction with the COSY-TOF spectrometer

The p p → p K0 Σ+ reaction was investigated with the TOF spectrometer at COSY at 3.059   GeV / c incident beam momentum. The main objective was to clarify whether or not a narrow exotic S = + 1 resonance, the Θ+ pentaquark, is populated at 1.53   GeV / c2 in the p K0 subsystem with a data sample of much higher statistical significance compared to the previously reported data in this channel. An analysis of these data does not confirm the existence of the Θ+ pentaquark. This is expressed as an upper limit for the cross section σ (p p → Σ+ Θ+) < 0.15   μb at the 95% confidence level. © 2007 Elsevier B.V. All rights reserved.