The Panofsky ratio and photopion production cross section at threshold on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ are investigated in a softpion approach to the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$→${}_{}{}^3{}_{}{}^{}\mathrm{H}$ weak axial-vector form factor. Results are compared with data on $\beta$ decay and electron magnetic scattering, as well as with calculations based on "exact" $A=3\mathrm{}$ wave functions previously obtained by solving the Faddeev equations in the coordinate representation.

NUCLEAR REACTIONS Calculations on ${\pi }^{-}\left(\mathrm{stopped}\right)+{}_{}{}^3{}_{}{}^{}\mathrm{He}\to \gamma +{}_{}{}^3{}_{}{}^{}\mathrm{H}$, ${\pi }^{-}\left(\mathrm{stopped}\right)+{}_{}{}^3{}_{}{}^{}\mathrm{He}\to {\pi }^0+{}_{}{}^3{}_{}{}^{}\mathrm{H}$, $\gamma \left(\mathrm{threshold}\right)+{}_{}{}^3{}_{}{}^{}\mathrm{He}\to {\pi }^{+}+{}_{}{}^3{}_{}{}^{}\mathrm{H}$. (${}_{}{}^3{}_{}{}^{}\mathrm{He}$→${}_{}{}^3{}_{}{}^{}\mathrm{H}$) weak axial-vector form factor. Model three-nucleon wave functions.

• Received 25 October 1977

DOI:https://doi.org/10.1103/PhysRevC.18.944