A study of experimental sensitivities to proton parton distributions with xFitter

Abstract

In collider physics, parton distribution functions (PDFs) play a crucial role in computing theoretical cross sections for scattering reactions. This study explores how different experimental data sets influence extracted PDFs in CTEQ-TEA and MSHT NNLO PDF analyses. To gauge the impact of experimental data, including the HERA and ZEUS combined charm and beauty production, LHCb 7 TeV charm and beauty production, CMS 7 TeV W+c production, and CMS 13 TeV inclusive jets, I utilize the $L_2$ sensitivity statistical indicator in the Hessian framework as a visual representation of their respective impacts. This sensitivity quantifies the statistical pulls on individual data sets against the best-fit PDFs, facilitating the identification of tensions among competing data sets. Using the QCD fitting framework xFitter, I extract the necessary values for plotting $L_2$ sensitivities for ten distinct data sets implemented in the program, employing recent PDF sets from the CTEQ-TEA and MSHT groups. The computed $L_2$ sensitivities estimate the potential impact of the examined data sets.

Comments: 13 pages, 13 figures, 1 table