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Universality and scaling in perturbative QCD at small x

We present a pedagogical review of the universal scaling properties displayed by the structure function F_2 at small x and large Q^2 as measured at HERA. We first describe the derivation of the double asymptotic scaling of F_2 from the leading-order Altarelli-Parisi equations of perturbative QCD. Un...

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Detalles Bibliográficos
Autores principales: Forte, Stefano, Ball, Richard D.
Lenguaje:eng
Publicado: 1995
Materias:
Acceso en línea:http://cds.cern.ch/record/292347
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author Forte, Stefano
Ball, Richard D.
author_facet Forte, Stefano
Ball, Richard D.
author_sort Forte, Stefano
collection CERN
description We present a pedagogical review of the universal scaling properties displayed by the structure function F_2 at small x and large Q^2 as measured at HERA. We first describe the derivation of the double asymptotic scaling of F_2 from the leading-order Altarelli-Parisi equations of perturbative QCD. Universal next-to-leading order corrections to scaling are also derived. We explain why the universal scaling behaviour is spoiled when the initial distributions rise too steeply by considering the nonsinglet distribution F_2^p-F_2^n as an explicit example. We then examine the stability of double scaling to the inclusion of higher order singularities, explaining how the perturbative expansion at small x can be reorganized in such a way that each order is given by the sum of a convergent series of contributions which are of arbitrarily high order in the coupling. The wave-like nature of perturbative evolution is then shown to persist throughout almost all the small x region, giving rise asymptotically to double scaling for a wide class of boundary conditions.
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 1995
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spelling cern-2923472022-08-13T02:25:04Zhttp://cds.cern.ch/record/292347engForte, StefanoBall, Richard D.Universality and scaling in perturbative QCD at small xParticle Physics - PhenomenologyWe present a pedagogical review of the universal scaling properties displayed by the structure function F_2 at small x and large Q^2 as measured at HERA. We first describe the derivation of the double asymptotic scaling of F_2 from the leading-order Altarelli-Parisi equations of perturbative QCD. Universal next-to-leading order corrections to scaling are also derived. We explain why the universal scaling behaviour is spoiled when the initial distributions rise too steeply by considering the nonsinglet distribution F_2^p-F_2^n as an explicit example. We then examine the stability of double scaling to the inclusion of higher order singularities, explaining how the perturbative expansion at small x can be reorganized in such a way that each order is given by the sum of a convergent series of contributions which are of arbitrarily high order in the coupling. The wave-like nature of perturbative evolution is then shown to persist throughout almost all the small x region, giving rise asymptotically to double scaling for a wide class of boundary conditions.We present a pedagogical review of the universal scaling properties displayed by the structure function F_2 at small x and large Q^2 as measured at HERA. We first describe the derivation of the double asymptotic scaling of F_2 from the leading-order Altarelli-Parisi equations of perturbative QCD. Universal next-to-leading order corrections to scaling are also derived. We explain why the universal scaling behaviour is spoiled when the initial distributions rise too steeply by considering the nonsinglet distribution F_2^p-F_2^n as an explicit example. We then examine the stability of double scaling to the inclusion of higher order singularities, explaining how the perturbative expansion at small x can be reorganized in such a way that each order is given by the sum of a convergent series of contributions which are of arbitrarily high order in the coupling. The wave-like nature of perturbative evolution is then shown to persist throughout almost all the small x region, giving rise asymptotically to double scaling for a wide class of boundary conditions.hep-ph/9512208CERN-TH-95-323EDINBURGH-95-560CERN-TH-95-323EDINBURGH-95-560oai:cds.cern.ch:2923471995-12-01
spellingShingle Particle Physics - Phenomenology
Forte, Stefano
Ball, Richard D.
Universality and scaling in perturbative QCD at small x
title Universality and scaling in perturbative QCD at small x
title_full Universality and scaling in perturbative QCD at small x
title_fullStr Universality and scaling in perturbative QCD at small x
title_full_unstemmed Universality and scaling in perturbative QCD at small x
title_short Universality and scaling in perturbative QCD at small x
title_sort universality and scaling in perturbative qcd at small x
topic Particle Physics - Phenomenology
url http://cds.cern.ch/record/292347
work_keys_str_mv AT fortestefano universalityandscalinginperturbativeqcdatsmallx
AT ballrichardd universalityandscalinginperturbativeqcdatsmallx