Pseudovector versus pseudoscalar coupling in kaon photoproduction reexamined - art. no. 068201

The question of pseudovector versus pseudoscalar coupling schemes for the k aon-hyperon-nucleon interaction is reexamined for the reaction gamma p-->K( +)Lambda in several isobaric models. These models typically include Born te rms, K* and K-l exchanges in the t channel, and a few different combination s of spin-1/2 baryon resonances in the s and u channels. The coupling const ants are obtained by fitting to a large data set. We find that both pseudos calar and pseudovector couplings can allow for a satisfactory description o f the present database. The resulting coupling constants, g(K Lambda N) and g(K Sigma N), in the pseudovector coupling scheme are smaller than those p redicted using flavor SU(3) symmetry, but consistent with the values obtain ed in a QCD sum rule calculation.