Measurements of the proton structure at HERA and their impact for LHC

Recent results on proton structure functions from H1 and ZEUS Collaborations are presented. The data have been recorded in e+p and e−p collisions for both Neutral Current and Charged Current reactions, covering a wide kinematic range of squared four-momentum transfers Q2, from 0.2GeV2 to 30000GeV2, and Bjorken x between ∼5⁎10−6 and 0.65. Data from both experiments have been combined, leading to significantly reduced experimental uncertainties. The combined measurements are analysed in a NLO QCD fit, and a set of parton density functions, HERAPDF1.0, is extracted from these data alone. New direct measurements of the structure function FL, making use of dedicated low energy runs of the HERA machine, are also presented. The impact of the HERA data on the parton density functions and predictions for LHC is discussed.