Influence of N*-resonances on hyperon production in the channel pp->K+ Lambda p at 2.95, 3.20 and 3.30 GeV/c beam momentum

TL;DR

This study investigates hyperon production near threshold energies in proton-proton collisions, revealing the influence of N*-resonances and final-state interactions through detailed cross-section measurements and Dalitz plot analysis.

Contribution

It provides new exclusive data on hyperon production at three beam energies and identifies the varying influence of N*-resonances and final-state interactions in the process.

Findings

Strong N(1650) resonance influence at 2.95 GeV/c

Increasing contribution of N(1710)/N(1720) resonances at higher energies

Significant impact of pΛ final-state interaction

Abstract

Hyperon production in the threshold region was studied in the reaction pp -> K+Lp using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at the three different beam momenta of p_beam=2.95, 3.20 and 3.30 GeV/c, corresponding to excess energies of epsilon=204, 285 and 316 MeV, respectively. Total cross-sections were deduced for the three beam momenta to be 23.9+/-0.8 +/-2.0 ub, 28.4+/-1.3 +/-2.2 ub and 35.0+/-1.3 +/-3.0 ub. Differential observables including Dalitz plots were obtained. The analysis of the Dalitz plots reveals a strong influence of the N(1650)-resonance at p_beam=2.95 GeV/c, whereas for the higher momenta an increasing relative contribution of the N(1710)- and/or of the N(1720)-resonance was observed. In addition, the pL-final-state interaction turned out to have a significant influence on the Dalitz plot distribution.