^12,13C(p, π^-) ^13,14O_g.s. reactions in the Δ₁₂₃₂ resonance region

The role of the Δ resonance has been discussed for the ^12,13,14C(p, π^-)^13,14,15O_g.s. reactions both experimentally and theoretically. Recent calculations suggested resonance effects in the energy dependence of the differential cross section that seem to contradict existing data. Since the available data points are limited, it is important to measure the energy dependence of the differential cross sections and the analyzing powers in order to better understand the still unclear reaction mechanism of the ground state (p, π^-) reactions. In the present paper, angular distributions of the differential cross sections and the analyzing powers were measured for ^12,13C(p, π^±) reactions at incident energies of 250, 300, and 350 MeV. Experimental results for the ¹²C(p, π^-)¹³O_g.s. reaction are compared with full-range distorted-wave Born approximation calculations.