Search for in the exclusive proton-induced reaction at the energy of 70 GeV
A search for narrow , a candidate for pentaquark baryon with positive strangeness, has been performed in an exclusive proton-induced reaction on carbon nuclei or quasifree nucleons at E beam = 70 GeV ( GeV) studying nK + , pK S 0 and pK L 0 decay channels of in four different final states of the system. In order to assess the quality of the identification of the final states with neutron or K 0 L , we reconstructed and decays in the calibration reactions and . We found no evidence for narrow pentaquark peak in any of the studied final states and decay channels. Assuming that the production characteristics of the system are not drastically different from those of the and systems, we established upper limits on the cross-section ratios 0.02 and 0.15 at 90% CL and a preliminary upper limit for the forward hemisphere cross-section 30 nb/nucleon.
© Società Italiana di Fisica and Springer-Verlag, 2004