Total cross sections of the charge exchange reaction $({\pi }^{+},{\pi }^0)$ on ${}^2$H, ${}^3$He, and ${}^4$He across the $\Delta \mathrm{}\left(1232\right)\mathrm{}$ resonance

Results from a $4\pi$ solid angle measurement of the inclusive reaction $({\pi }^{+},{\pi }^0)$ on ${}^2$H, ${}^3$He, and ${}^4$He at incident pion energies of $T_{{\pi }^{+}}=70\mathrm{}$, 118, 162, 239, and 330 MeV are presented. The single charge exchange total cross sections were determined, and are compared to previous results and simple models of $\pi$–few-nucleon interactions. On the helium isotopes a strong damping of the cross sections in the $\Delta \mathrm{}\left(1232\right)\mathrm{}$ energy region is observed. Total cross sections of the breakup reaction ${\pi }^{+}{+}^2$H $\to {\pi }^{+}\mathrm{pn}$ are also given.