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The pp->K+ n Sigma+ reaction near threshold

Yu. Valdau·V. Koptev·S. Barsov·M. Büscher·S. Dymov·M. Hartmann·A. Kacharava·S. Merzliakov·S. Mikirtychyants·A. Mussgiller·M. Nekipelov·R. Schleichert·H. Ströher·C. Wilkin
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Abstract

Inclusive K+ production in proton-proton collisions has been measured at a beam energy of 2.16 GeV using the COSY-ANKE magnetic spectrometer. The resulting spectrum, as well as those corresponding to K+ p and K+ pi+ correlated pairs, can all be well described using consistent values of the total cross sections for the pp->K+ p Lambda, pp->K+ p Sigma0, and pp->K+ n Sigma+ reactions. While the resulting values for Lambda and Sigma0 production are in good agreement with world data, our value for the total Sigma+ production cross section, sigma(pp->K+ n Sigma+) = 2.5+/-0.6(stat)+/-0.4(syst) mkb at an excess energy of epsilon=129 MeV, could only be reconciled with other recently published data if there were a highly unusual near--threshold behaviour.

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Yu. Valdau, V. Koptev, S. Barsov, M. Büscher, S. Dymov, M. Hartmann, A. Kacharava, S. Merzliakov, S. Mikirtychyants, A. Mussgiller, M. Nekipelov, R. Schleichert, H. Ströher, C. Wilkin. 2007-03-27. The pp->K+ n Sigma+ reaction near threshold. https://doi.org/10.1016/j.physletb.2007.07.018

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