RENORMALIZATION OF THE ONE-BODY OFF-DIAGONAL COULOMB FIELD IN NUCLEI

Isospin violation effects in nuclei are investigated within a microsco pic approach which takes into account the influence of the residual st rong interaction on the Coulomb interaction. The renormalization of th e off-diagonal Coulomb field acting within a nucleus, by the residual strong interaction is calculated analytically in a simplified RPA. Fro m the expression for the suppression coefficient of the isospin violat ing part of the Coulomb field, the isospin violating spreading widths of isobaric analog states are derived. The resulting reduction of the width is in agreement with the data on the isospin symmetry restoratio n and with some earlier evaluations of the isospin violating spreading widths. (C) 1997 Elsevier Science B.V.