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arXiv · hep-ph/0007142

The soft-gluon current at one-loop order

S. Catani·M. Grazzini
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Abstract

We study the soft limit of one-loop QCD amplitudes and we derive the process-independent factorization formula that controls the singular behaviour in this limit. This is obtained from the customary eikonal factorization formula valid at tree (classical) level by introducing a generalized soft-gluon current that embodies the quantum corrections. We compute the explicit expression of the soft-gluon current at one-loop order. It contains purely non-abelian correlations between the colour charges of each pair of hard-momentum partons in the matrix element. This leads to colour correlations between (two and) three hard partons in the matrix element squared. Exploiting colour conservation, we recover QED-like factorization for the square of the matrix elements with two and three hard partons.

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S. Catani, M. Grazzini. 2000-07-13. The soft-gluon current at one-loop order. https://doi.org/10.1016/s0550-3213(00)00572-1

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