The Nuclear Response in Delta - Isobar Region in the ( 3 He , t ) Reaction

The excitation of a ∆-isobar in a finite nucleus in charge–exchange (3 He,t) reaction is discussed in terms of a nuclear response function. The medium effects modifying a ∆-and a pion propagation were considered for a finite size nucleus. The Glauber approach has been used for distortion of a 3 He and a triton in the initial and the final states. The effects determining the peak positions and its width are discussed. Large displacement width for the ∆-h excitations and considerable contribution of coherent pion production were found for the reaction on 12 C.