Study of the reaction γp → K + Λ(1520) at photon energies up to 2.65 GeV

The reaction γp → K + Λ (1520) was measured in the energy range from threshold to 2.65 GeV with the SAPHIR detector at the electron stretcher facility ELSA in Bonn. The Λ (1520) production cross-section was analyzed in the decay modes pK − , nK̅^0 , Σ ± π ∓ , and Λπ + π − as a function of the photon energy and the squared four-momentum transfer t . While the cross-sections for the inclusive reactions rise steadily with energy, the cross-section of the process γp → K + Λ (1520) peaks at a photon energy of about 2.0 GeV, falls off exponentially with t , and shows a slope flattening with increasing photon energy. The angular distributions in the t -channel helicity system indicate neither a K nor a K * exchange dominance. Rather, the rapid change of the angular distribution with energy suggests that, in addition to t -channel K and K * exchange, amplitudes for formation of nucleon resonances in the s -channel play an important role.