Forward-angle coincident electroproduction cross sections of charged pions from ${}^3\mathrm{He}$ have been measured at electron energies $E_0=855\mathrm{}$, 675, 600, and 555 MeV. The overall features of the data for energy transfers of $\omega =370\mathrm{}$ to 430 MeV with pions detected along the momentum transfer axis are reproduced in terms of a microscopic model, including pole terms, final state rescattering and produced and preformed $\Delta$ resonances. Separation of the cross section into its longitudinal and transverse parts was performed at $Q^2=0.045(\mathrm{GeV}/c{)}^2$. The longitudinal part of the cross section in the ${\pi }^{+}$ channel does not contradict with the assumption of a preformed ${\Delta }^{++}$.

• Received 29 April 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.2396