The Bethe-Heitler theory of pair production by photons and of bremsstrahlung by electrons is compared with observations of these processes in a liquid-hydrogen bubble chamber. Agreement between theory and experiment is found within the statistical limits of the experiment which are typically ∼ ½% of the total cross sections studied. The form of the experiment also allows limits to be set on the production of new particles of mass less than 100 MeV in high-energy hadronic collisions.

• Received 17 April 1972

DOI:https://doi.org/10.1103/PhysRevD.7.26