Interpretation of the angular distribution of theHe4(π−,n)3H reaction based on theΔ-hole model

The angular distribution and the magnitude of the cross section of the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(${\pi }^{\mathrm{-}}$,n${)}^3$H reaction for pion kinetic energies from 100 to 250 MeV are reasonably well reproduced in the framework of the Δ-hole model with an improved overlap function 〈${\psi }_{{\mathrm{}}^3\mathrm{H}\mathrm{\Vert }{\psi }_{{\mathrm{}}^4\mathrm{He}\mathrm{〉}}}$. It is pointed out that the Δ-hole formation dominates the reaction in the forward region while the one nucleon mechanism becomes more important at larger angles.