BRST Symmetric Gaugeon Formalism for the Higgs Model

We reinvestigate Yokoyama’s gaugeon formalism for the spontaneously broken Abelian gauge theory. Within the framework of the covariant linear gauges, we give a general gauge-fixing Lagrangian which includes the gauge field, the Goldstone mode, the multiplier B-field and Yokoyama’s gaugeon fields (as well as Faddeev-Popov ghosts). As special choices of the values of the gauge-fixing parameters, our theory includes the usual covariant gauges and Rξ-like gauges. Although some of the gauge-fixing parameters can be shifted by the q-number gauge transformation, the ξ parameter cannot be shifted in any of the Rξ-like gauges. In the standard formalism of canonically quantized gauge theories,1)–3) we do not consider gauge transformations on the quantum level. There is no quantum gauge freedom, since the quantum theory is defined only after the gauge fixing. Yokoyama’s gaugeon formalism4)–9) provides a broader framework within which we can conside