Polarized Proton-Proton Bremsstrahlung

The analyzing power for proton-proton bremsstrahlung has been measured at TRIUMF with 280-MeV polarized protons. All three outgoing particles were detected in coincidence. After appropriate cuts were applied, over 160 000 $\mathrm{pp}\gamma$ events remained, an order of magnitude more than in previous $\mathrm{pp}\gamma$ experiments. The analyzing-power measurements are in good agreement with calculations based on modern potential models of the $\mathrm{NN}$ interaction, but disagree with the predictions of the soft-photon approximation.