V. Chekelian, A. Dubak, A. Nikiforov, S. Habib, A. Raspiareza, S. Shushkevich Analysis webpage
Abstract
A measurement of the longitudinal proton structure function $F_{L}(x,Q^{2})$ derived
from inclusive deep inelastic $ep$ scattering cross section measurements at high $Q^{2}$
with the H1 detector at HERA is presented. The data were taken in the year 2007 at
a positron beam energy of $E_{e}=27.5$~GeV and proton beam energies $E_{p}$ of 920~GeV,
575~GeV and 460~GeV. The measurements of the NC cross sections from this analysis
combined with the reported earlier NC cross section measurements for the same data
periods at medium $Q^{2}$ allowed to measure $F_{L}(x,Q^{2})$
in a range of high four-momentum transfer squared $12 \leq Q^2 \leq 800~$GeV$^2$ and
correspondingly Bjorken-$x$ between $0.00028\leq x \leq 0.0353$. The measured longitudinal structure function is found to be consistent with the NLO QCD calculations.