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arXiv · 0805.2809

Measurement of the Proton Structure Function F_L at Low x

H1 Collaboration
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Abstract

A first measurement is reported of the longitudinal proton structure function F_L(x,Q^2) at the ep collider HERA. It is based on inclusive deep inelastic e^+p scattering cross section measurements with a positron beam energy of 27.5 GeV and proton beam energies of 920, 575 and 460 GeV. Employing the energy dependence of the cross section, F_L is measured in a range of squared four-momentum transfers 12 < Q^2 < 90 GeV^2 and low Bjorken x 0.00024 < x < 0.0036. The F_L values agree with higher order QCD calculations based on parton densities obtained using cross section data previously measured at HERA.

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H1 Collaboration. 2008-06-04. Measurement of the Proton Structure Function F_L at Low x. https://doi.org/10.1016/j.physletb.2008.05.070

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