Decay of the Isoscalar Giant Resonances inPb208

The decay of the giant-resonance region in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ has been studied in a ${\alpha }^{\prime }-\gamma$ angular correlation experiment via the reaction chain ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$($\alpha$, ${\alpha }^{\prime }$)${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ ${}_{}{}^{\mathrm{GR}}{}_{}{}^{}\mathrm{}\left(n\right)\mathrm{}$ ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$*($\gamma$)${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$. The correlation functions are in agreement with the assumption of predominant $E2\mathrm{}$ strength for the resonance around $E_x=10.9\mathrm{}$ MeV, but require considerable strengths of excitation modes higher than $E0\mathrm{}$ for the resonance around $E_x=13.7\mathrm{}$ MeV. The coincident $\alpha$-particle spectra show significant fine structure in the giant-resonance region.