Pion single-charge exchange in light nuclei

Abstract

The (π +, π°) reaction on nuclei 7Li, 10B and 13C is studied in the framework of the first order pion-nucleus optical potential. Several optical potentials resulting from different off-shell extrapolations of the (πN) t-matrix are used in the calculations. The spin dependent term in the t-matrix is included in the calculations. Transitions to both analog and non-analog states are examined. In most cases the calculation is performed using the distorted wave impulse approximation. The 13C nucleus received special attention and the (π +, π 0) calculation to the analog state is performed using the method of coupled channels which includes the (π +, π +) and (π +, π 0) channels. In the case of 13C we examine the contributions of two step processes in which giant states serve as intermediate states. The excitation functions of the (π +, π 0) reaction in the above three nuclei are compared with the recent experimental results.