New data on the reaction at Ep = 70 GeV and the search for exotic baryons
The SPHINX Collaboration (IHEP-ITEP)
S.V. Golovkin1 - A.P. Kozhevnikov1 - V.P. Kubarovsky1 - V.F. Kurshetsov1 - L.G. Landsberg1 - V.V. Molchanov1 - V.A. Mukhin1 - S.V. Petrenko1 - V.A. Senko1 - D.V. Vavilov1 - V.A. Victorov1 - V.Z. Kolganov2 - G.S. Lomkatsi2 - A.F. Nilov2 - V.T. Smolyankin2
1 State Research Center, Institute for High Energy Physics, Protvino, Russia
2 State Research Center, Institute of Theoretical and Experimental Physics, Moscow, Russia
Received: 28 April 1999 Communicated by V.V. Anisovich
New data for the diffractive reaction 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 a structure at the threshold region with a mass 1810 MeV and a distinct X(2000) peak with MeV and 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 . We also present new results on the narrow threshold structure X(1810) with MeV and MeV which is produced in the region of very small P2T<0.01 GeV2. The possibility of the Coulomb production mechanism for X(1810) is discussed.
13.85.Fb Inelastic scattering: two particle find state - 25.40.Ve Other reactions above meson production thresholds (energies >400 MeV)