Giant monopole resonance strength in ²⁸Si

The giant resonance region in ²⁸Si was studied with inelastic scattering of 240 MeV α particles at small angles including 0°. The giant resonance peak extended from E_x=12 MeV to 35 MeV and E0 strength corresponding to 54±6% of the isoscalar E0 energy weighted sum rule was identified between E_x=11–35 MeV with a centroid of 21.5±0.3 MeV and an rms width of 5.9±0.2 MeV. E2 strength corresponding to 32±5% of the isoscalar E2 sum rule was identified with a centroid of E_x=19.0±0.2 MeV and rms width of 1.7±0.2 MeV. Elastic scattering was measured from θ_c.m.=3° to 47° and optical parameters obtained. Inelastic scattering to states at 1.78, 6.88, 10.2, and 11.1 MeV was measured and deformation lengths and L components extracted.