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IHEP 98 - 30
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| S.V.Golovkin, A.P.Kozhevnikov, V.P.Kubarovsky, V.F.Kurshetsov, L.G.Landsberg, V.V.Molchanov, V.A.Mukhin, S.I.Petrenko, V.A.Senko, D.V.Vavilov, V.A.Victorov(IHEP, Protvino, Russia), V.Z.Kolganov, G.S.Lomkatzi, A.F.Nilov, V.T.Smolyankin (ITEP, Moscow, Russia ) | ||
| New Data on the p+N --> [Sigma - K+]+N Reaction at E_=70 GeV and the Search for Exotic Baryons | ||
| Protvino, 1999.-p.14, figs.8, tables 1, refs.:28. | ||
New data for the diffractive reaction $p+N \rightarrow [\Sigma^oK^+]+N$ at $E_p$=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 $M(\Sigma^oK^+)$ a structure at the threshold region with a mass $\sim$1810~MeV and a distinct $X(2000)$ peak with $M=1989\pm6$~MeV and $\Gamma=91\pm20$~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 cryptoexotic pentaquark baryon with hidden strangeness $|qqqs\bar s>$. We also present new results on the narrow threshold structure X(1810) with $M=1807\pm7$~MeV and $\Gamma=62\pm19$~MeV which is produced in the region of very small $P^2_T<$0.01~GeV$^2$. The possibility of the Coulomb production mechanism for X(1810) is discussed.
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