COHERENT GAMMA-PRODUCTION IN (P,P') REACTIONS IN NUCLEI IN THE DELTA-RESONANCE REGION

We study the process of coherent photon production in nuclei induced b y the (p,pl) reaction around the Delta excitation region. The cross se ctions are about 200 times smaller than the corresponding ones for coh erent pion production but within measurable range with present machine s. The cross section selects the transverse part of the NN --> N Delta transition, while coherent pion production selects the longitudinal o ne. The reactions are complementary and show different aspects of Delt a h propagation through the nucleus which are discussed here. (C) 1998 Elsevier Science B.V.