Longitudinal-Transverse Separations of Structure Functions at Low $Q^2$ for Hydrogen and Deuterium

We report on a study of the longitudinal to transverse cross section ratio, $R={\sigma }_L\mathrm{/}{\sigma }_T$, at low values of $x$ and $Q^2$, as determined from inclusive inelastic electron-hydrogen and electron-deuterium scattering data from Jefferson Lab Hall C spanning the four-momentum transfer range 0.06 $ < Q^{2} < 2.8$GeV$^{2}$\mathrm{.}Evenatthelowestvaluesof$Q^{2}$,$R$ remains nearly constant and does not disappear with decreasing $Q^2$, as expected. We find a nearly identical behaviour for hydrogen and deuterium.