Abstract
Inclusive ep double differential cross sections for neutral current deep inelastic scattering are measured with the H1 detector at HERA. The data were taken with a lepton beam energy of 27.6 GeV and two proton beam energies of Ep=460 and 575 GeV corresponding to centre-of-mass energies of 225 and 252 GeV, respectively. The measurements cover the region of 6.5×10−4≤x≤0.65 for 35≤Q2≤800 GeV 2 up to y=0.85 . The measurements are used together with previously published H1 data at Ep=920 GeV and lower Q2 data at Ep=460 , 575 and 920 GeV to extract the longitudinal proton structure function FL in the region 1.5≤Q2≤800 GeV 2 .