Analyzing power measurements forp-dradiative capture

Analyzing power measurements are presented for radiative capture of polarized protons on deuterium and for polarized deuterons on hydrogen at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=3.33 MeV. The reaction is dominated by E1 capture from channel-spin ${\mathit{S}}_{\mathit{c}}$=1/2 states; however, the measurements show clear evidence of M1, E2, and spin-flip (${\mathit{S}}_{\mathit{c}}$=3/2) E1 contributions at the 1/2% level. The new data can impose fairly strong constraints on individual matrix elements.