Improved study of a possible Theta+ production in the pp -> p K0 sigma+   reaction with the COSY-TOF spectrometer
  The pp -> p K0 Sigma+ 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 resnance, the Theta+ pentaquark, is populated at 1.53 GeV/c2 in the K0 p 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 Theta+ pentaquark. This is expressed as an upper limit for the cross section sigma (pp -> p K0 Sigma+) < 0.15 microbarn at the 95 percent confidence level. 
COSY-TOF collaboration, M. Abdel-Bary, S. Abdel-Samad, K.-Th.   Brinkmann, R. Castelijns, H. Clement, J. Dietrich, S. Dshemu...