Proton Decay in a Nucleus Revisited ---Pionic Effects---

The importance of pionic currents in the eventual proton decay in thenucleus is discussed. Processes with one pion emitted by the decayingnucleon and subsequently, reabsorbed by some other nucleon, turns out to belittle relevant, mainly due to the presence of a ``hard-core'' in N-Ninteractions. On the other hand, although the decay into two pions isconsiderably enhanced in the nucleus, its relative importance is still smallbecause of the smallness of the corresponding branching-ratio in free-spacedecay. Finally, some general comments of interest in the problem of nucleondecay in the nucleus are presented.