Dipole resonances in He-4

We investigated the analogs of the giant dipole resonance (GDR) and spin-dipole resonance (SDR) of He-4 by using the He-4(Li-7,Be-7) reaction at an incident energy of 455 MeV and at forward scattering angles. The Delta S=0 and Delta S-1 spectra for He-4 were obtained by measuring the 0.43-MeV Be-7 gamma-ray in coincidence with the scattered Be-7. From the Delta S= 0 and Delta S=1 spectra thus obtained, the strength distributions of the GDR and SDR in He-4 can be derived and the results are compared with the previous data.