pp -> pK(+) Lambda reaction in an effective Lagrangian model - art. no. 055213

We investigate the pp-->pK(+)Lambda reaction within an effective Lagrangian model where the contributions to the amplitudes are taken into account wit hin the tree level. The initial interaction between the two nucleons is mod eled by the exchange of pi, rho, omega, and sigma mesons, and the Lambda K production proceeds via the excitation of the N*(1650), N*(1710), and N*(1 720) baryonic resonances. The parameters of the model at the nucleon-nucleo n-meson vertices are determined by fitting the elastic nucleon-nucleon scat tering with an effective interaction based on the exchange of these four me sons, while those at the resonance vertices are calculated from the known d ecay widths of the resonances as well as the vector meson dominance model. Available experimental data is described well by this approach. The one-pio n-exchange diagram dominates the production process at both higher and lowe r beam energies. The rho and omega meson exchanges make negligible contribu tions. However, the sigma-exchange processes contribute substantially to th e total cross sections at lower beam energies. The excitation of the N*(171 0) and N*(1650) resonances dominate this reaction at beam momenta above and below 3 GeV/c, respectively. The interference among the amplitudes of vari ous resonance excitation processes is significant. For beam energies very c lose to the K+ production threshold the hyperon-proton final state interact ion effects are quite important. The data is selective about the model used to describe the low-energy scattering of the two final state baryons. [S05 56-2813(99)02211-6].