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arXiv · hep-ph/9503344

Finite Width Effects and Gauge Invariance in Radiative $W$ Production and Decay

U. Baur·D. Zeppenfeld
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Abstract

The naive implementation of finite width effects in processes involving unstable particles can violate gauge invariance. For the example of radiative $W$ production and decay, $q\bar q' \to \ellνγ$, at tree level, it is demonstrated how gauge invariance is restored by including the imaginary part of triangle graphs in addition to resumming the imaginary contributions to the $W$ vacuum polarization. Monte Carlo results are presented for the Fermilab Tevatron.

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U. Baur, D. Zeppenfeld. 1995-03-15. Finite Width Effects and Gauge Invariance in Radiative $W$ Production and Decay. https://doi.org/10.1103/physrevlett.75.1002

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