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The Search for Pentaquark Baryon with Hidden Strangeness

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 نشر من قبل Dmitri Vavilov
 تاريخ النشر 1999
  مجال البحث
والبحث باللغة English
 تأليف L. G. Landsberg




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Evidences for new baryon states with mass >1.8 GeV were obtained in the experiments of the SPHINX Collaboration in studying hyperon-kaon mass spectra in several proton diffractive reactions. The main result of these experiments is the observation of X(2000)->SIGMA K state with unusual dynamical features (narrow width, anomalously large branching ratios for the decay channels with strange particle emission). The possibility of the interpretation of this state as cryptoexotic pentaquark baryon with hidden strangeness is discussed. The additional data which are supported the real existence of X(2000) baryon are also presented.



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81 - L. G. Landsberg 1999
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 da ta 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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