The One-Loop Effective Potential in Non-Linear Gauges

We calculate the 1-loop effective potential of an Abelian Higgs model within the R_{\xi/\sigma} class of non-linear gauges that preserves the Higgs-boson low-energy theorem. The R_{\xi/\sigma} gauge involves two gauge-fixing parameters \xi and \sigma, and is a renormalizable extension of the Feynman--'t Hooft R_\xi set of gauges beyond the 1-loop level. By taking consistently into account Goldstone--gauge-boson mixing effects, we show how the 1-loop effective potential evaluated at its extrema is independent of both \xi and \sigma, in agreement with the Nielsen identity. The 1-loop constant and wavefunction renormalizations are presented within this non-linear R_{\xi/\sigma} class of gauges.