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Search for exotic baryon resonances at NA49

Results of the search for baryon resonances with exotic quantum numbers in p+p interactions at 158 GeV beam energy will be presented. A narrow Xi-pi- baryon resonance with mass of 1.862 +/- 0.002 GeV/c2 and width below the detector resolution of 0.018 GeV/c2 is observed. This state is identified as a candidate for the hypothesized exotic Xi--5 baryon with and a quark content of (ds ds ubar). In the Xi-pi+ invariant mass spectrum at the same mass, an indication is observed of a candidate of the Xi05 member of this isospin quartet with a quark content of (ds us dbar). The corresponding antibaryon spectra show indications of enhancements at the same location.

pentaquark; observation; exotic; NA49

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