EPJ

2023 Impact factor 4.2
EPJ C - Particles and Fields
Particles and Fields

Eur. Phys. J. C 10, 363-372
DOI 10.1007/s100529900013

Charged particle cross sections in photoproduction and extraction of the gluon density in the photon

The H1 Collaboration

C. Adloff34 - et al.

34 Fachbereich Physik, Bergische Universität Gesamthochschule Wuppertal, Wuppertal, Germany

Received: 8 October 1998 / Published online: 8 September 1999

Abstract
Photoproduction data collected with the H1 detector at HERA in 1994 are used to study the cross-sections for inclusive charged particle production and the structure of the photon. The differential cross-sections ${\rm d}\sigma/{\rm d}p_T^2, $ for $\vert\eta\vert < 1$ in the HERA laboratory frame, and ${\rm d}\sigma/{\rm d}\eta$ for pT> 2GeV/c and pT> 3GeV/c have been measured. Model calculations of these cross-sections, based on perturbative QCD, indicate that the results are sensitive to the parton densities of the photon as well as to higher order effects, which are phenomenologically treated by multiple interactions. This sensitivity is exploited to determine the leading order $x_{\gamma}$ distribution of partons in the photon using a new method based on high pT charged particles. The gluon content of the photon is extracted and found to rise with decreasing $x_{\gamma}$.

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