Experimental test of pion exchange and PCAC in proton-nucleus charge exchange reactions at 144 MeV

The differential cross sections of the (p,n) reaction on 6Li, 12C, and 14N to the ground state of the final nuclei at E/sub p/ = 144 and 0 < theta/sub LAB/ < 200 were measured. The quantum numbers of these transitions, like those in Gamow-Teler beta decay, have ΔJ = 1, ΔT = 1, and ΔP = 0, which is consistent with the one-pion exchange mechanism. Differential cross sections were calculated with the absorption modified one-pion exchange model. The nucleus was treated as an elementary particle, as first suggested by Kim and Primakoff. Using the partially conserved axial vector current hypothesis (PCAC) the magnitude and momentum dependence of the initial nucleus-pion-final nucleus coupling constant, g/sub NπN'/, was obtained from beta decay and inelastic electron scattering, respectively. The calculations, which had no free parameters, were found to agree with the data for 6Li and 12C, but not for 14N. 14 references