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Gauge Invariance in Boson Production

Robin G. Stuart
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Abstract

It is shown how to construct exactly gauge-invariant S-matrix elements for processes involving unstable gauge particles such as the $W$ and $Z^0$ bosons. The results are applied to derive a physically meaningful expression for the cross-section $σ(e^+e^-\to Z^0Z^0)$ and thereby provide a solution to the long-standing problem of the unstable particle. The problem of maintaining QED gauge-invariance in the process $e^+e^-\to\barν_e e^-W^+\to\barν_e e^-u\bar d$ is examined.

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Robin G. Stuart. 1997-06-20. Gauge Invariance in Boson Production. https://arxiv.org/abs/hep-ph/9706431

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