Gardi, E. and Magnea, L. (2009) Infrared singularities in QCD amplitudes. Il nuovo cimento C, 32 (5\6). pp. 137-157. ISSN 1826-9885
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Abstract
We review recent progress in determining the infrared singularity structure of on-shell scattering amplitudes in massless gauge theories. We present a simple ansatz where soft singularities of any scattering amplitude of massless partons, to any loop order, are written as a sum over colour dipoles, governed by the cusp anomalous dimension. We explain how this formula was obtained, as the simplest solution to a newly-derived set of equations constraining the singularity structure to all orders. We emphasize the physical ideas underlying this derivation: the factorization of soft and collinear modes, the special properties of soft gluon interactions, and the notion of the cusp anomaly. Finally, we briefly discuss potential multi-loop contributions going beyond the sum-over-dipoles formula, which cannot be excluded at present.
| Item Type: | Article |
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| Uncontrolled Keywords: | Gauge field theories ; Quantum chromodynamics ; Summation of perturbation theory |
| Subjects: | 500 Scienze naturali e Matematica > 530 Fisica |
| Depositing User: | Marina Spanti |
| Date Deposited: | 27 Mar 2020 10:17 |
| Last Modified: | 27 Mar 2020 10:17 |
| URI: | http://eprints.bice.rm.cnr.it/id/eprint/16736 |
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