NONPERTURBATIVE CHIRAL APPROACH TO S-WAVE (K)OVER-BARN INTERACTIONS

The s-wave meson-nucleon interaction in the S = -1 sector is studied b y means of coupled-channel Lippmann-Schwinger equations, using the low est order chiral Lagrangian and a cut off to regularize the loop integ rals. The method reproduces successfully the Lambda(1405) resonance an d the K(-)p --> K(-)p, (K) over bar(0)n, pi(0)Lambda, pi(0)Sigma, pi()Sigma(-), pi(-)Sigma(+) cross sections at low energies. The inclusion of the eta Lambda,eta Sigma(0) channels in the coupled system is foun d very important and allows a solution in terms of only the lowest ord er Lagrangian. (C) 1998 Elsevier Science B.V.