Feynman rules for the rational part of the electroweak 1-loop amplitudes in the Rξ gauge and in the unitary gauge

We present the complete set of Feynman rules producing the rational terms of kind R2 needed to perform any 1-loop calculation in the Electroweak Standard Model. Our formulae are given both in the Rξ gauge and in the Unitary gauge, therefore completing the results in the ’t Hooft-Feynman gauge already presented in a previous publication.As a consistency check, we verified, in the case of the process H → γγ and in a few other physical cases, the independence of the total Rational Part (R1 +R2) on the chosen gauge. In addition, we explicitly checked the equivalence of the limits ξ→∞ after or before the loop momentum integration in the definition of the Unitary gauge at 1-loop.

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