He) Reactions

Recently, deeply bound pionic states were found experimentally in (d, 3 He) reactions on 208 Pb. They found an isolated peak structure in the bound region below the pion production threshold. We study theoretically these excitation functions in (d, 3 He) reactions on 208 Pb at T d =600 MeV. We found very good agreement with the (d, 3 He) excitation functions and could identify the underlying structures of the pionic states. We study the energy dependence of the (d, 3 He) reactions and the change of the excitation functions with the incident energy. The existence of deeply bound pionic atoms in heavy nuclei was predicted by Toki and Yamazaki as quasi-static states 1),2). Since then many efforts were made for detection of these states both experimentally and theoretically 3)−10). In particular, it is worth mentioning that (n,d) reactions 9) and (p,pp) reactions 10) on the 208 Pb target were able to identify some strength in the excitation function below the pion production threshold. It is, however, not yet convincing due to the lack of good resolution and good statistical accuracy. It was, hence, badly needed to perform the similar experiments with better resolution and statistical accuracy for identification of isolated peak structure in the bound region below the pion production threshold. Very recently, Yamazaki et.al. performed such experiments with the use of (d, 3 He) reactions on 208 Pb with better resolution and statistical accuracy 11). They, at last, succeeded to identify clearly a peak structure in the bound region. The results were presented in the recent publication with the theoretical predictions, which were made before the experiments were performed 6). The agreement of the theoretical predictions to the newly obtained experimental data is almost perfect. In this paper, we would like to describe in detail the theoretical part of the (d, 3 He) reaction on 208 Pb. We should describe the underlying structures of the (d, 3 He) excitation functions. At the same time, we would like to show the spectrum with better resolution to predict what should be expected when experiments were performed with better (feasible) resolution. In addition, we would like to show the energy dependence of the excitation function of the (d, 3 He) reaction with the 208 Pb target. We describe the (d, 3 He) reaction within the effective number approach. The (d, 3 He) cross sections use the experimental cross section and the …