The role of the Λ(1405) in the pp → pK+Λ(1405) reaction

We report a theoretical study of the pp -> pK(+)Lambda(1405) reaction, which was recently investigated at COSY-Julich by using a 3.65 GeV/c circulating proton beam incident on an internal hydrogen target. The reaction is driven by single-kaon exchange, single-pion exchange, and single-rho exchange terms which have very different shapes due to the two-pole structure of the Lambda(1405) and the presence of background terms. The shape for the sum of the three contributions, as well as the total cross-section, are consistent with present data within experimental and theoretical uncertainties, using reasonable form factors for the meson-baryon vertices.