( , ) shows a giant dipole resonance.

PHYSICS · Multi-part · Fermi University Physics · Nuclear Physics · The nuclear force and nuclear models · The nuclear force and nuclear models

The Nucleus Resolved, Ch Collective motion: the deformed nucleus, vibrations, rotations and giant resonances

Problem

{}^{90}\mathrm{Zr}

(

Z=40

N=50

) shows a giant dipole resonance. ((a)) Estimate its centroid energy using

E_{\rm GDR} \approx 78A^{-1/3}\,\mathrm{MeV}

. ((b)) Evaluate the classical dipole sum rule

60NZ/A\,\mathrm{MeV\,mb}

. ((c)) A measurement finds the resonance carries a total integrated cross section of

1250\,\mathrm{MeV\,mb}

. What fraction of the sum rule is this?