Quantum electrodynamics in electron--positron systems

A short review of the current status of quantum electrodynamics (QED) is presented, in addition to background material on this subject, new material first presented at this SLAC symposium is summarized. All three experimental processes e+e- → e+e-, e+e- → μ+μ-, e+e- → γγ are examined and are shown to be in accord with the predictions of QED. The first two processes are given correctly by QED even up to center-of-mass energies of 7.1 and 7.4 GeV respectively. The available results in the third process are restricted to 5.2 GeV. Radiative corrections are applied and allow appropriate quantitative limits of validity of QED to be expressed in several parametric forms. Polarization effects in e+e- collisions are described, and experiments on the Lyman-α transition in positronium are discussed