Analog of the giant dipole resonance in He4

We studied the giant dipole resonance (GDR) in He-4 by observing its analog via the He-4(Li-7,Be-7) reaction at an incident energy of 455 MeV and at forward scattering angles. The spin-nonflip (Delta S=0) spectrum was deduced by measuring the 0.43-MeV Be-7 gamma-ray in coincidence with the scattered Be-7. The total cross section of photodisintegration to the GDR in He-4 was derived from the Delta S=0 and Delta L=1 spectrum. The result agrees well with the previous total photodisintegration data in which the GDR has a pronounced peak at E-gamma similar to 27 MeV.