A.M. Eiro

4He D-State Effects in the 2H(d/γ) 4He Reaction at Low Energies

Large tensor force effects have recently been reported in the 2He(d,γ) 4He reaction induced by polarized deuterons [1,2,3]. For deuteron energies Ed is essentially determined by the He S-state, and B= , C= , D= by the 4He D-state. It is well known [2] that the angular distributions of the tensor analyzing powers (TAP) are very sensitive to the value of the asymptotic D/S state ratio P in the d+d cluster configuration of He. This effect can be observed for deuteron energies near 10 MeV where the dominant amplitudes are A and C. As the deuteron energy decreases, the transition amplitude from the 5S2 scattering state becomes dominant due to the absence of the centrifugal barrier. The amplitudes B and A become of the same order of magnitude while C is negligible. Therefore large D state effects are also expected at low energies and the sensitivity to P can be observed either in the TAP or in the cross section [4].