engleski

Observation of a new Pentaquark Candidate State Xi3/2-- in pp Collisions with the NA49 Detector

Results of resonance searches in the Xi-pi-, Xi-pi+, Xibar+pi- and Xibar+pi+ invariant mass spectra in pp collisions at sqrt(s) = 17.2 GeV will be presented. A narrow 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 exotic Xi3/2-- pentaquark baryon with a quark content of (ds ds ubar). At the same mass an indication of a peak is observed in the Xi-pi+, Xibar+pi- and Xibar+pi+ invariant mass spectra. Also, preliminary results of resonance searches in other possible decay chains of the predicted pentaquark states will be presented.

observation; pentaquark; exotic; NA49

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