THE EFFECTIVE INDUCED PSEUDOSCALAR COUPLING-CONSTANT

The different mechanisms that contribute to the renormalization of the effective induced pseudoscalar coupling constant in nuclei are descri bed. For a nucleon in the nuclear medium one has to consider four diff erent induced pseudoscalar couplings, which are associated with the sp ace- and time-like parts of the current and the pseudovector source fu nction, respectively. All of these are renormalized in different ways in the medium. The net effect for weak processes with large time-like momentum transfer is a substantial quenching of the transition rates t hat increases with mass number in agreement with recent data on radiat ive muon capture on heavy nuclei.