Angular distributions of cross sections and analyzing powers were measured for the ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(p→,γ${)}^4$He reaction at incident proton energies of 2.0, 5.0, and 9.0 MeV. The 90° analyzing power was measured at 11 energies between 0.8 and 9.0 MeV. A transition matrix element analysis indicated that the inclusion of M1 strength gave better fits and eliminated the anomalously large ${}_{}{}^3{}_{}{}^{}\mathrm{D}_2^{}{}_{}{}^{}$ (E2) strength reported in earlier work. An E1-plus-E2 direct capture calculation was performed. It is shown that this calculation can be brought into agreement with the data if an M1 strength comparable to that found in the T-matrix element analysis (0.5–1.0% of the total capture cross section) is added.

• Received 13 September 1988

DOI:https://doi.org/10.1103/PhysRevC.39.352