The absolute differential cross section and analyzing powers ${\mathit{A}}_{\mathit{y}}$(θ), ${\mathit{A}}_{\mathit{y}\mathit{y}}$(θ), and ${\mathit{T}}_{20}$(θ) of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(d→,γ${)}^5$Li reaction have been measured with an 800 keV deuteron beam which was stopped in a gaseous ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ target. A transition matrix element analysis of the data leads to two solutions, both of which indicate the reaction proceeds predominantly through s-wave (E1) capture, with small admixtures of M1 radiation. One solution has predominantly ${}_{}{}^4{}_{}{}^{}$${\mathit{s}}_{3/2}$(E1) capture strength, the other has nearly equal capture strengths from the ${}_{}{}^2{}_{}{}^{}$${\mathit{s}}_{1/2}$(E1) and ${}_{}{}^4{}_{}{}^{}$${\mathit{s}}_{3/2}$(E1) transition matrix elements. Resonating group model (RGM) calculations have been performed which favor the solution with dominant ${}_{}{}^4{}_{}{}^{}$${\mathit{s}}_{3/2}$(E1) capture strength. In the RGM picture, the ‘‘fusion’’ resonance in the capture cross section is a consequence of the tensor force, which couples the [d${+}^3$He${]}_{\mathit{J}=3/2\mathrm{}}^{\mathit{S}=3/2\mathrm{}}$ scattering channel to the [p${+}^4$He${]}_{\mathit{J}=3/2\mathrm{}}^{\mathit{S}=1/2\mathrm{}}$ scattering channel, enabling the reaction to proceed via the ΔS=0 (E1) transition to the ground state. The finite tensor analyzing powers of the present experiment serve to support this interpretation of the role of the tensor force.

• Received 13 November 1991

DOI:https://doi.org/10.1103/PhysRevC.45.R487