Isoscalar high-energy octupole resonance in ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$ in inelastic electron scattering

The giant-resonance region in ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$ has been studied by inelastic electron scattering of the effective momentum transfer range $0.65\le q_{\mathrm{eff}}\le 1.18$ ${\mathrm{fm}}^{-1\mathrm{}}$. The high-energy octupole resonance was identified at $E_x=25\mathrm{}\pm 0.3$ MeV with a width of 6.3±0.3 MeV exhausting 39±4% of the $T=0\mathrm{}$ $E3\mathrm{}$ energy weighted sum rule. This result is in good agreement with a recent (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$') result and the recent random-phase approximation calculations, and its strength is inconsistent with the trend of low strength of the high-energy octupole resonances observed by inelastic proton scattering.

NUCLEAR REACTIONS ${}_{}{}^{92}{}_{}{}^{}\mathrm{Zr}$(e,e'), enriched target, $E_0=220\mathrm{}$ MeV, $\theta =32\mathrm{}°-61\mathrm{}°$, $q=0.65-1.18\mathrm{}$ ${\mathrm{fm}}^{-1\mathrm{}}$. Measured $\frac{d^2\sigma }{d\Omega d{E}_x}$ up to 33 MeV in excitation energy; deduced excitation energy, width, sum rule exhaustion of isoscalar high-energy octupole resonance.