The $\pi -{}_{}{}^3{}_{}{}^{}\mathrm{He}-{}_{}{}^3{}_{}{}^{}\mathrm{H}$ form factor $G_{\pi }\left(q^2\right)$ is calculated from a connection between the elementary particle method and the impulse approximation using a realistic wave function with an asymptotic tail. An analytic continuation is used for the timelike region. The $\pi -{}_{}{}^3{}_{}{}^{}\mathrm{He}-{}_{}{}^3{}_{}{}^{}\mathrm{H}$ coupling constant $G_{\pi }(-m_{\pi }^2)$ is found to be ≅ -1.7, in absolute value higher than the elementary nucleon value $g_{\pi }=1.41\mathrm{}$ because of the nuclear extension. The form factor is in very good agreement with results of dispersion relations. A determination which led to $G_{\pi }\approx -1.0\mathrm{}$ is shown to be wrong.

[NUCLEAR STRUCTURE ${}_{}{}^3{}_{}{}^{}\mathrm{He}$; calculated $\pi -{}_{}{}^3{}_{}{}^{}\mathrm{He}-{}_{}{}^3{}_{}{}^{}\mathrm{H}$ coupling constant.]

• Received 11 April 1983

DOI:https://doi.org/10.1103/PhysRevC.29.215