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arXiv · hep-ph/9410232

Zero-threshold expansion of two-loop self-energy diagrams

F. A. Berends·A. I. Davydychev·V. A. Smirnov·J. B. Tausk
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Abstract

An algorithm is constructed to derive a small momentum expansion for two-loop two-point diagrams in all cases where, due to the presence of physical thresholds, there are singularities at zero external momentum. The coefficients of this ``zero-threshold'' expansion are calculated analytically for arbitrary masses. Numerical examples, using diagrams occurring in the Standard Model, illustrate the convergence of the expansion below the first non-zero threshold.

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F. A. Berends, A. I. Davydychev, V. A. Smirnov, J. B. Tausk. 1994-10-06. Zero-threshold expansion of two-loop self-energy diagrams. https://doi.org/10.1016/0550-3213(95)00018-n

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