Inclusive electron-scattering measurements of Δ electroexcitation in nuclei are reported. Electrons with energies of 0.96, 1.1, 1.3, and 1.5 GeV were scattered from ${}_{}{}^1{}_{}{}^{}\mathrm{H}$, ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, C Fe, and W at 37.5°, corresponding to $Q^2$=0.20–0.52 (GeV/c${)}^2$ at the Δ peak. The centroid of the Δ-region cross-section peak is above that for the free nucleon and it shifts to higher invariant mass as $Q^2$ increases. The A dependence in the dip region and ratios of nuclear to nucleon integrated cross sections indicate that at these $Q^2$ values there is little specifically nuclear, e.g., quasideuteron, background contribution.

• Received 7 November 1988

DOI:https://doi.org/10.1103/PhysRevLett.62.1350