The impact of LHC measurements on the precision of the Parton Distribution Functions of the Proton

Recent measurements of top quark pair production cross section and triple- differential cross section for the Drell-Yan process, which are performed at the LHC, are studied using Hessian profiling technique to obtain their impact on the parton distribution functions (PDFs). It is explained how the Hessian profiling method may be used to assess the impact of these new data on PDFs and consequently on their predictions. We discuss issues observed with xFitter and the solutions we come up with. We establish the first comparison between the new software package, ePump (error PDF Updating Method Package) and xFitter. Special care is given to discuss the potential of each programs and the assumptions made of this theoretical framework compared to a treatment by the full global-analysis program.