Singular terms of helicity amplitudes at one loop in QCD and the soft limit of the cross sections of multi-parton processes

Zoltan Kunszt, Adrian Signer, Z. Trócsányi

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We describe a general method that enables us to obtain all the singular terms of helicity amplitudes of n-parton processes at one loop. The algorithm uses helicity amplitudes at tree level and simple color algebra. We illustrate the method by calculating the singular part of the one-loop helicity amplitudes of all 2 → 3 parton subprocesses. The results are used to derive the soft gluon limit of the cross sections of all 2 → 4 parton scattering subprocesses which provide a useful initial condition for the angular ordering approximation to coherent multiple soft gluon emission, incorporated in existing Monte Carlo simulation programs.

Original languageEnglish
Pages (from-to)550-564
Number of pages15
JournalNuclear Physics B
Issue number3
Publication statusPublished - Jun 6 1994


ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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