Giant monopole resonance strength in Ca-40

Abstract

The giant resonance region in Ca-40 was studied with inelastic scattering of 240 MeV alpha particles at small angles including 0 degrees. A peak at E-x = 17.5 +/- 0.4 MeV with Gamma = 4.95 +/- 0.25 MeV was found to contain 33 +/- 4% of the isoscalar E0 energy-weighted-sum-mle (EWSR) strength and 57 +/- 6% of the isoscalar E2 EWSR. Evidence was found for 92 +/- 15% of the isoscalar E0 EWSR between 8 < E-x < 29 MeV with a centroid of 18.9 +/- 0.4 MeV and a rms half width of 11.1 MeV but a definitive L = 0 assignment could not be made. The resulting E-GMR is in agreement with systematics from heavier nuclei.