Single-nucleon transfer to unbound states by means of the 4He(α, 3He) 5He reaction at 158 and 200 MeV
The 4He(α,3He)5He(g.s.) reaction was studied at incident laboratory energies of 158 and 200 MeV for c.m. scattering angles ranging from ∼16° to 100°. The shape of the 5He(g.s.) peak in the measured 3He energy spectra is well reproduced by distorted-wave Born approximation calculations. Whereas calculations utilizing six-parameter optical potentials yield good qualitative agreement with the measured angular distributions, unacceptably poor agreement is found when nine-parameter potentials are utilized. Absolute normalization with D20 strengths extracted from corresponding zero-range and finite-range calculations overpredicts the measurements by factors of ∼2 to 3.