High lying E0 strength in C-12

Abstract

The excitation region in C-12 from 7 MeV<E-x<60 MeV was studied with inelastic scattering of 240-MeV alpha particles at small angles including 0 degrees where E0 strength is enhanced. The strengths of known 0(+) states at E-x = 7.655 MeV and E-x = 10.3 MeV were obtained and E0 strength was observed to be distributed between E-x = 14 MeV and E-x = 30 MeV with a centroid of 21.5 +/- 0.4 MeV and an ms width of 3.1 +/- 0.2 MeV containing 14.5 +/- 4.0% of the isoscalar E0 energy-weighted sum rule. Angular distributions and strengths of the E-x =4.439 MeV 2(+), 9.641 MeV 3(-), and 10.844 MeV 1(-) states were also obtained. [S0556-2813(98)05704-5].