The $(W,Q^2)$ dependence of the ratio of inclusive electron scattering cross sections for ${}^{15}\mathrm{N}$/${}^{12}\mathrm{C}$ was determined in the kinematic ranges $0.8<W<2$ GeV and $0.2<Q^2<1$ GeV${}^2$ using 2.285 GeV electrons and the CLAS detector at Jefferson Lab. The ratios exhibit only slight resonance structure, in agreement with a simple phenomenological model and an extrapolation of deep-inelastic scattering ratios to low $Q^2$. Ratios of ${}^4\mathrm{He}$/${}^{12}\mathrm{C}$ using 1.6 to 2.5 GeV electrons were measured with very high statistical precision and were used to correct for He in the N and C targets. The $(W,Q^2)$ dependence of the ${}^4\mathrm{He}$/${}^{12}\mathrm{C}$ ratios is in good agreement with that of the phenomenological model and exhibit significant resonance structure centered at $W=0.94,1.23$, and 1.5 GeV.

• Received 17 December 2007

DOI:https://doi.org/10.1103/PhysRevC.78.015202