Path integral formulation of chiral gauge theories

One of the fundamental, and fascinating, problems of quantum field theories is that of anomalies. Whenever a classical-level symmetry is broken at the quantum level, an anomaly has occurred. These anomalous breakings of global symmetries entail no fatal consequence for the internal consistency of a theory. It is an entirely different situation, however, if the broken symmetry is a local gauge symmetry associated with either large or small transformations. The case of chiral gauge theories, where the left-handed and the right-handed parts of the fermion current couple differently to the gauge fields is discussed. General reviews of anomalies can be found elsewhere in the literature. (author)