Investigation of thePb208(p, p′)Reaction atE=54MeV

Abstract

Collective excitations of $^{208}\mathrm{Pb}$ were investigated by inelastic proton scattering at 54 MeV. The spectra covered the entire bound-state region for scattering angles between 11 and 58\ifmmode^\circ\else\textdegree\fi{}, and scattered particles were detected in a broad-range spectrograph with energy resolution \ensuremath{\approx} 35-40 keV full width at half maximum. The experimental angular distributions were compared to those predicted by distorted-wave Born-approximation calculations, utilizing a collective-model form factor. The location of the low-spin members of a sequence (${2}^{+}$-${8}^{+}$) of positive-parity states was confirmed. Likely candidates for $J>8$ states were found, as well as several collective fragments of ${3}^{\ensuremath{-}}$ and ${4}^{+}$ strengths. No appreciable fragmentation of the ${2}^{+}$ strength was found. Energy-weighted sum-rule strengths were estimated for all multipoles studied and were compared with the measured values.NUCLEAR REACTIONS $^{208}\mathrm{Pb}(p, {p}^{\ensuremath{'}})$, $E=54$ MeV; measured absolute $\ensuremath{\sigma}(E, \ensuremath{\theta})$. $^{208}\mathrm{Pb}$ levels, deduced $L$, ${{\ensuremath{\beta}}_{L}}^{2}$. Spectrograph.