COSY-TOF Research on Theta+
W. Eyrich, H. P. Morsch, Lothar Naumann, Luigi Pinna, W. T. Meyer, L. Filippi, Heinrich Mörtel, H. Clement, F. Stinzing, René Jäkel, M. Schulter-Wissermann, S. Abdel-Samad, S. Wirth, Jens-Christoph Georgi, Eberhard Kuhlmann, Karsten Möller, P. Schönmeier, L. Pizzolotto, H. Freiesleben, E. Doroshkevich · JuSER (Forschungszentrum Jülich) · 2005
Using the TOF detector at the COSY storage ring the hadronic reaction pp -> Sigma(+)K(0)p was measured exclusively at a beam momentum of 2.95 GeV/c. A narrow peak was observed in the invariant mass spectrum of the K(0)p subsystem at 1530 +/- 15 McV/c(2) with a significance of 4-6 standard deviations, depending on background assumptions. The upper limit of 18 +/- 4 MeV/c(2) (FWHM) for its width is given by the experimental resolution. Since a resonance in this subsystem must have strangeness S = +1 we claim it to be the Theta(+) state for which very recently evidence was found in various experiments. To come to a final decision on the existence of the Theta(+) very recently COSY-TOF performed a measurement which will give results with strongly improved statistical accuracy.