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Low- and high-mass components of the photon distribution functions

Schuler, Gerhard A. and Sjöstrand, Torbjörn LU orcid (1995) In Zeitschrift für Physik C Particles and Fields 68(4). p.607-623
Abstract

The structure of the general solution of the inhomogeneous evolution equations allows the separation of a photon structure function into perturbative ("anomalous") and non-perturbative contributions. The former part is fully calculable, and can be identified with the high-mass contributions to the dispersion integral in the photon mass. Properly normalized "state" distributions can be defined, where the {Mathematical expression} splitting probability is factored out. These state distributions are shown to be useful in the description of the hadronic event properties, and necessary for a proper eikonalization of jet cross sections. Convenient parametrizations are provided both for the state and for the full anomalous parton... (More)

The structure of the general solution of the inhomogeneous evolution equations allows the separation of a photon structure function into perturbative ("anomalous") and non-perturbative contributions. The former part is fully calculable, and can be identified with the high-mass contributions to the dispersion integral in the photon mass. Properly normalized "state" distributions can be defined, where the {Mathematical expression} splitting probability is factored out. These state distributions are shown to be useful in the description of the hadronic event properties, and necessary for a proper eikonalization of jet cross sections. Convenient parametrizations are provided both for the state and for the full anomalous parton distributions. The non-perturbative parts of the parton distribution functions of the photon are identified with the low-mass contributions to the dispersion integral. Their normalizations, as well as the value of the scale Q0 at which the perturbative parts vanish, are fixed by approximating the low-mass contributions by a discrete, finite sum of vector mesons. The shapes of these hadronic distributions are fitted to the available data on F2 γ(x, Q2). Parametrizations are provided for Q0=0.6 GeV and Q0=2 GeV, both in the DIS and the {Mathematical expression} factorization schemes. The full parametrizations are extended towards virtual photons. Finally, the often-used "FKP-plus-TPC/2γ" solution for F2 γ(x, Q2) is commented upon.

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publication status
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in
Zeitschrift für Physik C Particles and Fields
volume
68
issue
4
pages
17 pages
publisher
Springer
external identifiers
  • scopus:34249758195
ISSN
0170-9739
DOI
10.1007/BF01565260
language
English
LU publication?
yes
id
b95e592f-e3fb-4762-b6dc-d8f6cf1d7123
date added to LUP
2019-04-29 23:29:43
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2024-04-02 00:36:10
@article{b95e592f-e3fb-4762-b6dc-d8f6cf1d7123,
  abstract     = {{<p>The structure of the general solution of the inhomogeneous evolution equations allows the separation of a photon structure function into perturbative ("anomalous") and non-perturbative contributions. The former part is fully calculable, and can be identified with the high-mass contributions to the dispersion integral in the photon mass. Properly normalized "state" distributions can be defined, where the {Mathematical expression} splitting probability is factored out. These state distributions are shown to be useful in the description of the hadronic event properties, and necessary for a proper eikonalization of jet cross sections. Convenient parametrizations are provided both for the state and for the full anomalous parton distributions. The non-perturbative parts of the parton distribution functions of the photon are identified with the low-mass contributions to the dispersion integral. Their normalizations, as well as the value of the scale Q<sub>0</sub> at which the perturbative parts vanish, are fixed by approximating the low-mass contributions by a discrete, finite sum of vector mesons. The shapes of these hadronic distributions are fitted to the available data on F<sub>2</sub>                            <sup>γ</sup>(x, Q<sup>2</sup>). Parametrizations are provided for Q<sub>0</sub>=0.6 GeV and Q<sub>0</sub>=2 GeV, both in the DIS and the {Mathematical expression} factorization schemes. The full parametrizations are extended towards virtual photons. Finally, the often-used "FKP-plus-TPC/2γ" solution for F<sub>2</sub>                            <sup>γ</sup>(x, Q<sup>2</sup>) is commented upon.</p>}},
  author       = {{Schuler, Gerhard A. and Sjöstrand, Torbjörn}},
  issn         = {{0170-9739}},
  language     = {{eng}},
  month        = {{12}},
  number       = {{4}},
  pages        = {{607--623}},
  publisher    = {{Springer}},
  series       = {{Zeitschrift für Physik C Particles and Fields}},
  title        = {{Low- and high-mass components of the photon distribution functions}},
  url          = {{http://dx.doi.org/10.1007/BF01565260}},
  doi          = {{10.1007/BF01565260}},
  volume       = {{68}},
  year         = {{1995}},
}