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arXiv · hep-ph/9506417

Gauge Invariance and Unstable Particles

Joannis Papavassiliou·Apostolos Pilaftsis
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Abstract

A gauge-independent approach to resonant transition amplitudes with nonconserved external currents is presented, which is implemented by the pinch technique. The analytic expressions derived with this method are $U(1)_{em}$ invariant, independent of the choice of the gauge-fixing parameter, and satisfy a number of required theoretical properties, including unitarity. Although special attention is paid to resonant scatterings involving the $γWW$ and $ZWW$ vertices in the minimal Standard Model, our approach can be extended to the top quark or other unstable particles appearing in renormalizable models of new physics.

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Joannis Papavassiliou, Apostolos Pilaftsis. 1995-06-26. Gauge Invariance and Unstable Particles. https://doi.org/10.1103/physrevlett.75.3060

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