Results are presented for the charge-symmetry superratio R, simple ratios ${\mathit{r}}_1$ and ${\mathit{r}}_2$, and the differential cross sections of ${\mathrm{\pi }}^{+}$ and ${\mathrm{\pi }}^{\mathrm{-}}$ elastic scattering on ${}_{}{}^3{}_{}{}^{}\mathrm{H}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$: R=${\mathit{r}}_1$${\mathit{r}}_2$, ${\mathit{r}}_1$=σ(θ)[${\mathrm{\pi }}^{+}$ ${}_{}{}^3{}_{}{}^{}\mathrm{\pi }_{}^{+}{}_{}{}^{}$ ${}_{}{}^3{}_{}{}^{}]$/σ(θ)[${\mathrm{\pi }}^{\mathrm{-}}$ ${}_{}{}^3{}_{}{}^{}\mathrm{\pi }_{}^{\mathrm{-}}{}_{}{}^{}$ ${}_{}{}^3{}_{}{}^{}]$, and ${\mathit{r}}_2$=σ(θ)[${\mathrm{\pi }}^{\mathrm{-}}$ ${}_{}{}^3{}_{}{}^{}\mathrm{\pi }_{}^{\mathrm{-}}{}_{}{}^{}$ ${}_{}{}^3{}_{}{}^{}]$/σ(θ)[${\mathrm{\pi }}^{+}$ ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ →${\mathrm{\pi }}^{+}$ ${}_{}{}^3{}_{}{}^{}]$. The measurements were made at ${\mathit{T}}_{\mathrm{\pi }}$=180 MeV and ${\mathrm{\theta }}_{\mathrm{\pi }}$(lab)=40°–90°; some data were obtained at ${\mathit{T}}_{\mathrm{\pi }}$=143 MeV also. At all angles, R>1 and ${\mathit{r}}_2$>1 indicative of a violation of charge symmetry; however, we also find that ${\mathit{r}}_1$≃1. Our data are consistent with ${\mathit{F}}_{\mathit{p}}$${(}^3$H)≃${\mathit{F}}_{\mathit{n}}$${(}^3$He) and ${\mathit{F}}_{\mathit{n}}$${(}^3$H)>${\mathit{F}}_{\mathit{p}}$${(}^3$He), where ${\mathit{F}}_{\mathit{p}}$ and ${\mathit{F}}_{\mathit{n}}$ are the proton and neutron matter form factors. σ(θ)[${\mathrm{\pi }}^{\pm }$ ${}_{}{}^3{}_{}{}^{}\mathrm{\pi }_{}^{\pm }{}_{}{}^{}$ ${}_{}{}^3{}_{}{}^{}]$ decreases with increasing magnitude of the four-momentum transfer t up to ${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≃70°; the t dependence of the F ’s is comparable to that of the electromagnetic form factors. σ(θ)[${\mathrm{\pi }}^{\mathrm{-}}$ ${}_{}{}^3{}_{}{}^{}\mathrm{\pi }_{}^{\mathrm{-}3}{}_{}{}^{}$H] has a non-spin-flip dip at ${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$≃78°.

• Received 14 December 1989

DOI:https://doi.org/10.1103/PhysRevC.41.2770