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Search for Exotic Baryons with Hidden Strangeness in the Experiments of the Sphinx Collaboration in Diffractive and Coulomb Production Processes

L. G. Landsberg
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Abstract

Experimental results of the SPHINX Collaboration on studying proton diffractive production processes are presented. Evidences for new baryon states with masses >1.8 GeV were obtained in hyperon-kaon effective mass spectra in several reactions. New data for the diffractive reaction p+N->[Sigma0 K+]+N at Ep=70 GeV were obtained with partially upgraded SPHINX setup. The data are in a good agreement with the results of our previous study of this reaction. In the mass spectrum M(Sigma0 K+) a structure at the threshold region with a mass about 1800 MeV and a distinct X(2000) peak with M=1989+/-6 MeV and Gamma=91+/-20 MeV are observed. Unusual features of the massive X(2000) state (narrow decay width, anomalously large branching ratio for the decay channel with strange particle emission) make it a serious candidate for a cryptoexotic pentaquark baryon with hidden strangeness |qqqs sbar>. We also present new results on the narrow threshold structure X(1810) with M=1807+/-7 MeV and Gamma=62+/-19 MeV which is produced in the region of very small pt**2<0.01 GeV**2. The possibility of the Coulomb production mechanism for X(1810) is discussed.

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L. G. Landsberg. 1999-07-16. Search for Exotic Baryons with Hidden Strangeness in the Experiments of the Sphinx Collaboration in Diffractive and Coulomb Production Processes. https://arxiv.org/abs/hep-ex/9907025

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