Investigation of the mechanism of inelastic alpha-particle scattering on 28Si nuclei by the method of angular αγ correlations at Eα = 30.3 MeV

The angular dependence of the differential cross sections for alpha-particle scattering on 28Si nuclei and double-differential cross sections for the reaction 28Si(α, αγ)28Si at Eα = 30.3 MeV is measured for the case of alpha-particle emission angle between 20° and 160° and the excitation of low-lying states of the 28Si nucleus (0+, ground state; 2+ state at 1.78 MeV; 4+ state at 4.62 MeV; 0+ state at 4.96 MeV; and 3− + 4+, 6.88 MeV + 6.89 MeV). The spin-tensor components of the density matrix for the 2+ state at 1.78 MeV and the 4+ state at 4.62 MeV in the 28Si* nucleus are reconstructed in a modelindependent way. Seven rank-6 components are reconstructed for the 3− state at 6.88 MeV. Orientation features of 28Si* are determined. The experimental data in question are compared with the results of the calculations performed under the assumption of the collective-excitation mechanism and by the coupled-channel method.