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Exotic baryon resonances in p+p interactions with the NA49 detector

A search for baryon resonance states with exotic quantum numbers was performed in p+p interactions at 158 GeV beam energy with the large acceptance NA49 detector at the Cern SPS. A narrow \Xi^{; ; -}; ; \pi^{; ; -}; ; baryon resonance with mass of 1.862 &plusmn ; ; 0.002 GeV/c^{; ; 2}; ; and width below the detector resolution of \approx 0.018 GeV/c^{; ; 2}; ; is observed. This state is identified as a candidate for the hypothesized exotic \Xi^{; ; --}; ; _{; ; 5}; ; baryon with S=-2, I=3/2 and a quark content of (dsds\bar{; ; u}; ; ). In the \Xi^{; ; -}; ; \pi^{; ; +}; ; invariant mass spectrum at the same mass, an indication is observed of a candidate of the \Xi^{; ; 0}; ; _{; ; 5}; ; member of this isospin quartet with a quark content of (dsus\bar{; ; d}; ; ). The corresponding antibaryon spectra show indications of enhancements at the same location.

NA49; p+p; pentaquark state; exotic

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