An experiment to determine the bremsstrahlung cross section in proton-$\alpha$-particle scattering was performed for incident proton energies between 7.0 and 12.0 MeV. It was found that in order to obtain agreement with the measured coplanar values, the theoretical calculation must include the contribution of the so-called "rescattering term."

• Received 23 June 1971

DOI:https://doi.org/10.1103/PhysRevLett.27.271