Structure of weak currents

The review summarizes the present knowledge on neutral-current physics and compares it with the standard weak interaction theory. The main conclusions which may be drawn from experimental studies are pointed out by discussing especially those data which do not rely too much on model-dependent assumptions. The theoretical framework for describing the electroweak interaction processes is provided in a historical and phenomenological approach. The structure of charged-currents is briefly reviewed. The space-time structure of the neutral weak force is elucidated. Therefore, experimental results based on the analysis of neutrino interactions with electrons and hadrons are dealt with. Additional information is extracted from pority-violating effects in muon-hadron, electron-hadron as well as electron-positron reactions. The empirical status of the neutral-current parameters is listed showing excellent agreement with the standard model's expectations. Some outstanding problems are discussed