Electroweak Interaction in Polarized Electron-Positron and Electron-Electron Scattering

Abstract

The discovery of renormalization through spontaneous symmetry breaking in non-Abelian gauge theories is one of the most important results in theoretical physics during the last decade. In this manner it has been possible to create an (almost) unified theory of electrodynamics and weak interaction. Further results along these lines are quantum chromodynamics and grand unification theories. However, up to now there is no definite experimental verification of the theory of electroweak interaction either in the standard form (Salam and Weinberg) or with a more complicated gauge group. So far, experiments on weak interaction can still be described with an old-fashioned four-fermion interaction with an additional, neutral current. There are especially no experimental indications for the predicted intermediate bosons like the W± and the Z0. These particles cannot yet be produced because accelerator energies are still too small. But one could ask for their influence on precise experiments in quantum electrodynamics (QED) as one does quite generally in testing QED.1 Unfortunately, accuracy is still too small to see these effects in the anomalous magnetic moments of the electron and muon or the Lamb shift in hydrogen. On the other hand such effects could be seen already in the accessible energy range in sufficiently precise electronpositron annihilation experiments. Especially annihilation with polarized e± beams into muons could show these effects clearly. Unfortunately, these experiments have considerable experimental errors, which are up to now much too large to give a definite result in this direction.