Observation of a baryon resonance with positive strangeness in K+ collisions with Xe nuclei

The status of our investigation of low-energy K+Xe collisions in the xenon bubble chamber DIANA is reported. In the charge-exchange reaction K+Xe --> K(0)pXe', the spectrum of K(0)p effective mass shows a resonant enhancement with M = 1539 +/- 12 MeV/c(2) and Gamma less than or equal to 9 MeV/c(2). The statistical significance of the enhancement is near 4.4sigma. The mass and width of the observed resonance are consistent with expectations for the lightest member of the antidecuplet of exotic pentaquark baryons, as predicted in the framework of the chiral soliton model. (C) 2003 MAIK "Nauka/Interperiodica".