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Gauge invariance, gauge-parameter independence and properties of Green functions

Ansgar Denner·Stefan Dittmaier·Georg Weiglein
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Abstract

The application of the background-field method to the electroweak Standard Model is reviewed and further explored. Special emphasis is put on questions of gauge invariance and gauge-parameter (in-)dependence. Owing to the gauge invariance of the background-field effective action, the vertex functions obey simple Ward identities which imply important properties of the vertex functions. Carrying out the renormalization in a way respecting background-field gauge invariance leads to considerable simplifications. The generalization of the background-field method to the non-linear realization of the scalar sector of the Standard Model is illustrated. Furthermore, the interplay between gauge independence of the S-matrix and Ward identities of vertex functions is investigated. Finally, the Standard Model contributions to the $S$, $T$, and $U$ parameters are calculated and discussed within the background-field method.

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Ansgar Denner, Stefan Dittmaier, Georg Weiglein. 1995-05-10. Gauge invariance, gauge-parameter independence and properties of Green functions. https://arxiv.org/abs/hep-ph/9505271

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