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arXiv · hep-ph/9607309

A simple method for multi-leg loop calculations

R. Pittau
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Abstract

In this paper, I present a technique to simplify the tensorial reduction of one-loop integrals with arbitrary internal masses, but at least two massless external legs. By applying the method to rank l tensor integrals, one ends up with at most rank 1 tensor functions with the initial number of denominators, plus tensor integrals with less denominators and rank < l. To illustrate the algorithm, I explicitly compute diagrams contributing to processes of physical interest and show how the usual numerical instabilities due to the appearance of Gram determinants can be controlled.

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R. Pittau. 1997-03-27. A simple method for multi-leg loop calculations. https://doi.org/10.1016/s0010-4655(97)00065-9

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