Giant Magnetic Dipole States inPb208Observed in thePb207+nReaction

Abstract

High-resolution neutron transmission and elastic-scattering measurements on ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ have revealed a concentration of $p$-wave strength in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ which is mainly accounted for by $J^{\pi }=1^{+}$ resonances. The sum of the ground-state radiative widths for these resonances is $\Sigma {\Gamma }_{\gamma 0}=7.2\mathrm{}$ eV which agrees well with a one-particle-one-hole theoretical prediction which locates a fragment of the giant $M1\mathrm{}$ resonance at 7.50 MeV with ${\Gamma }_{\gamma 0}=9.3\mathrm{}$ eV.