Test of the Delta -hole model through the energy dependence of ( pi, pi ' gamma ) angular correlations on 12C.

For the reaction /sup 12/C(..pi..,..pi..')/sup 12/C/sup */( 2/sup +/,4.44 MeV), /sup 12/C/sup */..-->.. /sup 12/C (g.s.)+..gamma.., pion-..gamma.. angular correlations have been measured in and out of the reaction plane. The data taken at a pion momentum transfer of q = 0.47 fm/sup -1/ for incident kinetic energies of 116, 140, 162, 180, and 226 MeV confirm ..delta..-hole model predictions, in which the ..delta.. propagation in the nucleus is explicitly taken into account.