Hyperon production in the channel pp→K+Λp near the reaction threshold

Abstract Hyperon production in the threshold region was studied in the reaction pp → K + Λ p using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at three different beam momenta p beam = 2.59 , 2.68 and 2.85 GeV/ c (corresponding to excess energies of ɛ = 85 , 115 and 171 MeV). Total cross-sections were deduced to be 7.4 ± 0.5  μb , 8.6 ± 0.6  μb and 16.5 ± 0.4  μb , respectively. Differential observables including Dalitz plots were obtained. From the investigation of the Dalitz plot at p beam = 2.85  GeV / c a dominant contribution of the N ∗ ( 1650 ) -resonance to the reaction mechanism was found. In addition the pΛ -final-state interaction turned out to have a significant influence on the Dalitz plot distribution even 171 MeV above threshold.