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arXiv · hep-ph/0602178

The Cut-Constructible Part of QCD Amplitudes

Ruth Britto·Bo Feng·Pierpaolo Mastrolia
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Abstract

Unitarity cuts are widely used in analytic computation of loop amplitudes in gauge theories such as QCD. We expand upon the technique introduced in hep-ph/0503132 to carry out any finite unitarity cut integral. This technique naturally separates the contributions of bubble, triangle and box integrals in one-loop amplitudes and is not constrained to any particular helicity configurations. Loop momentum integration is reduced to a sequence of algebraic operations. We discuss the extraction of the residues at higher-order poles. Additionally, we offer concise algebraic formulas for expressing coefficients of three-mass triangle integrals. As an application, we compute all remaining coefficients of bubble and triangle integrals for nonsupersymmetric six-gluon amplitudes.

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Ruth Britto, Bo Feng, Pierpaolo Mastrolia. 2006-02-20. The Cut-Constructible Part of QCD Amplitudes. https://doi.org/10.1103/physrevd.73.105004

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