The absolute differential cross sections and vector and tensor analyzing powers for the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(d→,γ${)}^5$Li and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d→,γ${)}^5$He reactions have been measured both in the ${\mathit{j}}^{\mathrm{\pi }}$=3/$2^{+}$ fusion resonance region [${\mathit{E}}_{\mathit{d}}$(lab)=0.45 MeV and ${\mathit{E}}_{\mathit{d}}$(lab) = 0.1 MeV, respectively] and at ${\mathit{E}}_{\mathit{d}}$(lab)=8.6 MeV for several angles. In the fusion resonance region, a transition matrix element (TME) analysis of the observables leads to multiple solutions for both reactions, all of which indicate that the reactions proceed predominantly through s-wave (E1) capture, with small admixtures of M1 or E2 radiation. One solution for each reaction is dominated by a large (∼90%) ${}_{}{}^4{}_{}{}^{}$${\mathit{s}}_{3/2}$(E1) capture strength. Coupled-channels resonating group model (CCRGM) calculations have been performed which favor these solutions. In the CCRGM picture, the ${\mathit{j}}^{\mathrm{\pi }}$=3/$2^{+}$ fusion resonance in the capture cross section is a consequence of the tensor force, which couples the s=3/2, d${+}^3$He (or d${+}^3$H) channel to the s=1/2, p${+}^4$He (or n${+}^4$He) channel, enabling the reactions to proceed via the spin-independent (E1) transition to the ground state. At ${\mathit{E}}_{\mathit{d}}$(lab)=8.6 MeV, a TME analysis of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(d→,γ${)}^5$Li reaction yields a single solution which has >80% s-wave (E1) capture strength, whereas two TME solutions exist for the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(d→,γ${)}^5$He reaction with 45% and 65% s-wave (E1) capture strength. These data are also compared to the results of the CCRGM calculations.

• Received 16 March 1993

DOI:https://doi.org/10.1103/PhysRevC.49.912