Quasielastic electron scattering from ${}^{40}$Ca

Differential cross sections for quasielastic electron scattering on ${}^{40}$Ca have been measured at laboratory scattering angles of 45.5$°$, 90$°$, and 140$°$ with bombarding energies ranging from 130 to 840 MeV. Transverse and longitudinal response functions have been extracted for momentum transfers from 300 to 500 MeV/$c$. Contrary to some previously reported results, the total observed longitudinal strength agrees with the relativistic Fermi gas prediction to within $\pm$18%.