| Abstract: | The cross section for the $p(e,e\sp\prime\pi\sp+)n,\ d(e,e\sp\prime\pi\sp+)2n$ and $\sp3He(e,e\sp\prime\pi\sp+)\sp3H$ reactions are calculated using a simple model with pion, nucleon and $\Delta$-resonance degrees of freedom for the kinematical conditions used in a recent Saclay experiment. For the $d(e,e\sp\prime\pi\sp+)2n$ reaction, final state interactions between the two outgoing neutrons are found to have a large effect. The calculated quenching of the $\pi\sp+$ production cross section for the deuterium target is in agreement with that observed experimentally. It is predicted that due to the strong final state interactions in the singlet S state of the two neutrons, the $d(e,e\sp\prime\pi\sp+)2n$ cross section can have a large dependence on the orientation of the deuteron spin. For the $\sp3He(e,e\sp\prime\pi\sp+)\sp3H$ reaction, the quenching is predicted to be $\sim$0.4 which is in agreement with the unpublished results of the Mainz experiment. The four important contributions to the quenching are identified as: (i) the finite size i.e., the form factor of the trinucleons, (ii) the spin-isospin correlations in the trinucleons, (iii) the finite range of the propagation of the struck proton, and (iv) the possible pion-nucleon final state interactions. |
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