H-2(D,GAMMA)HE-4 POLARIZATION OBSERVABLES AT 20, 30, AND 50 MEV

Tensor and vector analyzing powers for the H-2(d, gamma)He-4 reaction have been obtained as a function of angle at E(d)(lab) = 20, 30, and 5 0 MeV. Differential cross sections were extracted at 30 and 50 MeV. Da ta for A(yy)(theta) and A(y)(theta) were obtained at all three energie s, while T20(theta) was also measured at E(d)(lab) = 50 MeV. A direct capture calculation was performed and compared to the data. This calcu lation assumes point deuterons and that the reaction proceeds primaril y via E2 radiation in this energy region. A value of 4% for the D-stat e probability arising from two-deuteron relative motion in the He-4 wa ve function was extracted by fitting the predictions of this model to the data. This calculation indicates that g-wave capture is significan t at the energies of the present experiment, a result which is support ed by a transition matrix element analysis of the data. The results of a microscopic 7-channel resonating group model (MCRGM) calculation ar e also compared to the data. This model takes all amplitudes having in coming angular momenta l less-than-or-equal-to 2 into account as well as the couplings to the n-He-3 and p-T channels. This microscopic calc ulation, which has produced reasonable agreement with the previous low energy data, predicts a value of 2.2% for the two-deuteron component of the D state in He-4. There is qualitative agreement with the presen t data.