High-Momentum Protons inPb208

High-momentum components of proton momentum distributions in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ have been studied from 300 to 500 MeV/c with the ($e,e^{\prime }p$) reaction. Cross sections were measured with 180 keV excitation-energy resolution for transitions to the low-lying ${\mathrm{½}}^{+}$, ${\frac{3}{2}}^{+}$, ${\frac{11}{2}}^{-}$, ${\frac{5}{2}}^{+}$, and ${\frac{7}{2}}^{+}$ states in ${}_{}{}^{207}{}_{}{}^{}\mathrm{Tl}$. The data are compared to distorted-wave impulse-approximation calculations with mean-field wave functions and with wave functions that include nucleon-nucleon correlations. The data are substantially larger than mean-field predictions. The observed excess strength at low excitation energy appears to be mainly due to long-range correlations and not to short-range and tensor correlations.