Improved study of a possible Θ+ production in the pp→pK0Σ+ reaction with the COSY-TOF spectrometer

The pp→pK0Σ+ reaction was investigated with the TOF spectrometer at COSY at 3.059GeV/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 1.53GeV/c2 in the pK0 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(pp→Σ+Θ+)<0.15μb at the 95% confidence level.