Density dependence of meson-nucleon vertices in nuclear matter

Changes in the meson-nucleon coupling constant and the vertex form factor i n nuclear matter are studied in a modified Skyrme Lagrangian including the sigma-meson field that satisfies the scale invariance. Renormalization of g (A), the axial-vector coupling constant, and the nucleon mass are studied i n a consistent model. The results are in good agreement with the empirical evidence. A calculation of the pi-N commutator, Sigma-term, indicates that the medium changes its magnitude considerably. (C) 1998 Published by Elsevi er Science B.V.