Proton Structure from HERA to LHC
Amanda Cooper-Sarkar
TL;DR
The paper analyzes how HERA data, especially from H1 and ZEUS, constrain proton parton distribution functions (PDFs) in the x region relevant to LHC W/Z production. It advocates an HERA-only PDF fit (HERAPDF1.0) using combined inclusive cross sections, enabling a precise, self-consistent determination of gluon, sea, and valence PDFs with a standard chi-squared criterion and without heavy-target corrections. It summarizes results from the inclusive data combination, the impact of charm data, low-energy runs, and updated HERA-I/II combinations, and discusses implications for W/Z predictions and lepton asymmetries at the LHC. The work provides a legacy dataset and a robust PDF input for LHC phenomenology, reducing uncertainties in high-energy cross-section predictions.
Abstract
The kinematic region covered by the LHC experiments probes low values of Bjorken-$x$. At the scale relevant for $W$ and $Z$ production the central rapidity region covers $10^{-3} < x < 10^{-1}$. This means that it is the HERA data which give the most insight into the behaviour of parton distribution functions (PDFs) for the early phase of running at the LHC. The H1 and ZEUS experiments are combining their data so as to provide a legacy of HERA results. The present status of the data combinations and the impact of these data on our knowledge of parton distribution functions is explored.