Residual interaction effects on deeply bound pionic states

Abstract

We have studied the residual interaction effects theoretically on the deeply bound pionic states which have been observed recently. In order to extract precise information on the pion-nucleus optical potential, we need to evaluate the residual interaction effects on the pionic states. The S-wave $\ensuremath{\pi}N$ interaction is used for the pion-nucleon residual interaction. We show that the complex eigenenergies vary typically about 0--20 keV and that the effects should be taken into account carefully in the analysis of data with high precision.