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arXiv · hep-ph/0311059

Infrared-Finite Amplitudes for Massless Gauge Theories

D. A. Forde·A. Signer
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Abstract

We present a method to construct infrared-finite amplitudes for gauge theories with massless fermions. Rather than computing $S$-matrix elements between usual states of the Fock space we construct order-by-order in perturbation theory dressed states that incorporate all long-range interactions. The $S$-matrix elements between these states are shown to be free from soft and collinear singularities. As an explicit example we consider the process $e^+ e^-\to 2$ jets at next-to-leading order in the strong coupling. We verify by explicit calculation that the amplitudes are infrared finite and recover the well-known result for the total cross section $e^+ e^-\to$ hadrons.

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D. A. Forde, A. Signer. 2004-03-23. Infrared-Finite Amplitudes for Massless Gauge Theories. https://doi.org/10.1016/j.nuclphysb.2004.02.024

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