Direct Evidence for a New Giant Resonance at <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>80</mn><mrow><msup><mrow><mi>A</mi></mrow><mrow><mo>−</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mn>3</mn></mrow></mfrac></mrow></msup></mrow></math></span> MeV in the Lead Region

M. N. Harakeh; K. van der Borg; T. Ishimatsu; H. P. Morsch; A. van der Woude; F. E. Bertrand

doi:10.1103/PhysRevLett.38.676

Direct Evidence for a New Giant Resonance at $80 A^{- \frac{1}{3}}$ MeV in the Lead Region

M. N. Harakeh, K. van der Borg, T. Ishimatsu, H. P. Morsch, A. van der Woude, and F. E. Bertrand

Phys. Rev. Lett. 38, 676 – Published 28 March 1977

Abstract

Inelastic $α$ scattering experiments at 120 MeV on ${}^{206, 208}{Pb}$ , ${}^{197}{Au}$ , and ${}^{209}{Bi}$ reveal the existence of a new isoscalar resonance located at $\sim 80 A^{- \frac{1}{3}}$ MeV in addition to the well-known resonance at $\sim 63 A^{- \frac{1}{3}}$ MeV. The angular distribution of this new resonance, though not inconsistent with an $E 4$ assignment, is better described by $E 0$ or $E 2$ . It would exhaust approximately 100%, 50%, or 17% of the corresponding isoscalar $E 0$ , $E 2$ , or $E 4$ energy-weighted sum rules, respectively.