2004/07/30 by Matthias F. M. Lutz, Madeleine Soyeur · 2 citations
Physics and Astronomy · #Amplitude #Baryon #Geometry #High-Energy Particle Collisions Research #Hyperon #Lambda #Meson #Nuclear physics #Particle physics #Particle physics theoretical and experimental studies #Physics #Pi #Pion #Proton #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Scattering #Scattering amplitude #Sigma #nucl-th
paper · pdf · doi:10.1016/j.nuclphysa.2004.11.007
published as Nucl.Phys.A748:499-512,2005 · 16 pages, 8 figures
arxiv created 2004/07/30 · openalex publication_date 2004/12/03 · arxiv updated 2010/12/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The γp → K+ π0 Λ and γp → K+ πΣ reactions are studied in the kinematic region where the π0 Λ(1116) and πΣ(1192) pairs originate dominantly from the decay of the Σ(1385) and Λ(1405) resonances. We consider laboratory photon energies around 2 GeV, significantly above the threshold for producing the K+ Σ(1385) and K+ Λ(1405) final states. We compute for both reactions the process in which the ingoing photon dissociates into a real K+ and a virtual K-, the off-shell K- scattering subsequently off the proton target to produce the π0 Λ or πΣ pair. The K- p → π0 Λ and K- p → πΣ amplitudes are calculated in the framework of a chiral coupled-channel effective field theory of meson-baryon scattering. The structure of the amplitudes reflects the dominance of the Λ(1405) in the πΣ channel and of the Σ(1385) in the πΛ channel. The full pion-hyperon final state interaction is included in these amplitudes. We extract from the calculated cross section the gauge-invariant double kaon pole term. We found this term to be large and leading to sizeable cross sections for both the γp → K+ π0 Λ and γp → K+ πΣ reactions, in qualitative agreement with the scarce data presently available. Accurate measurements of these cross sections should make it possible to extract the contribution of the double kaon pole and hence to assess the possibility of studying kaon-nucleon dynamics ust below threshold through these reactions.