High-Momentum Protons in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">Pb</mml:mi></mml:mrow><mml:mprescripts/><mml:mrow/><mml:mrow><mml:mn>208</mml:mn></mml:mrow><mml:mrow/><mml:mrow/></mml:mmultiscripts></mml:mrow></mml:math>

High-momentum components of proton momentum distributions in $^{208}\mathrm{Pb}$ have been studied from 300 to 500 MeV/c with the ($e,{e}^{\ensuremath{'}}p$) reaction. Cross sections were measured with 180 keV excitation-energy resolution for transitions to the low-lying ${\mathrm{\textonehalf{}}}^{+}$, ${\frac{3}{2}}^{+}$, ${\frac{11}{2}}^{\ensuremath{-}}$, ${\frac{5}{2}}^{+}$, 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.