  The analysis and the interpretation of the LHC data require a precise
determination of Parton Distribution Functions (PDFs) in order to detect
reliably potential signs of new physics. I present a systematic study designed
to assess the risk of absorbing, and thus missing, signals from heavy new
physics in the PDFs parameterisation during the High-Luminosity LHC run. I
discuss the consequences of such a PDF "contamination" and consider possible
solutions to it, for example the inclusion of other experimental data probing
large-x regions at low-energy.
