Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?

We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization formulae in which the singular collinear factor is universal...

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Detalles Bibliográficos
Autor principal: de Florian, Daniel Enrique
Publicado: 2012
Materias:
Hadronic colliders
NLO computations
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_11266708_v2012_n7_p_Catani
http://hdl.handle.net/20.500.12110/paper_11266708_v2012_n7_p_Catani
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_11266708_v2012_n7_p_Catani
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spelling paper:paper_11266708_v2012_n7_p_Catani2023-06-08T16:08:18Z Space-like (vs. time-like) collinear limits in QCD: Is factorization violated? de Florian, Daniel Enrique Hadronic colliders NLO computations We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization formulae in which the singular collinear factor is universal (process independent). We show that this strict (process-independent) factorization is not valid at one-loop and higher-loop orders in the case of the collinear limit in space-like regions (e.g., collinear radiation from initialstate partons). We introduce a generalized version of all-order collinear factorization, in which the space-like singular factors retain some dependence on the momentum and colour charge of the non-collinear partons. We present explicit results on one-loop and two-loop amplitudes for both the two-parton and multiparton collinear limits. At the level of squared amplitudes and, more generally, cross sections in hadron-hadron collisions, the violation of strict collinear factorization has implications on the non-abelian structure of logarithmically-enhanced terms in perturbative calculations (starting from the next-tonext-to-leading order) and on various factorization issues of mass singularities (starting from the next-to-next-to-next-to-leading order). © SISSA 2012. Fil:De Florian, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_11266708_v2012_n7_p_Catani http://hdl.handle.net/20.500.12110/paper_11266708_v2012_n7_p_Catani
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Hadronic colliders
NLO computations
spellingShingle Hadronic colliders
NLO computations
de Florian, Daniel Enrique
Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
topic_facet Hadronic colliders
NLO computations
description We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization formulae in which the singular collinear factor is universal (process independent). We show that this strict (process-independent) factorization is not valid at one-loop and higher-loop orders in the case of the collinear limit in space-like regions (e.g., collinear radiation from initialstate partons). We introduce a generalized version of all-order collinear factorization, in which the space-like singular factors retain some dependence on the momentum and colour charge of the non-collinear partons. We present explicit results on one-loop and two-loop amplitudes for both the two-parton and multiparton collinear limits. At the level of squared amplitudes and, more generally, cross sections in hadron-hadron collisions, the violation of strict collinear factorization has implications on the non-abelian structure of logarithmically-enhanced terms in perturbative calculations (starting from the next-tonext-to-leading order) and on various factorization issues of mass singularities (starting from the next-to-next-to-next-to-leading order). © SISSA 2012.
author de Florian, Daniel Enrique
author_facet de Florian, Daniel Enrique
author_sort de Florian, Daniel Enrique
title Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
title_short Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
title_full Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
title_fullStr Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
title_full_unstemmed Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?
title_sort space-like (vs. time-like) collinear limits in qcd: is factorization violated?
publishDate 2012
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_11266708_v2012_n7_p_Catani
http://hdl.handle.net/20.500.12110/paper_11266708_v2012_n7_p_Catani
work_keys_str_mv AT defloriandanielenrique spacelikevstimelikecollinearlimitsinqcdisfactorizationviolated
_version_ 1768546361151586304

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