Abstract

The interpretation of hadron collider, such as the LHC , data, and the assessment of possible hints of new physics, require the precise knowledge of the proton structure in terms of parton distribution functions (PDFs). In this talk, I present a systematic methodology designed to determine whether and how global PDF fits might inadvertently ‘fit away’ signs of new physics in the high-energy tails of the distributions. I showcase a scenario for the High- Luminosity LHC , in which the PDFs may completely absorb such signs of new physics, thus biasing theoretical predictions and interpretations. I discuss strategies to single out the effects in this scenario and disentangle the inconsistencies that stem from them. A first solution I discuss is the exploration of the synergy between the high luminosity programme at the LHC and present and future low-energy measurements of large-sea quark distributions. A second one, is to fit simultaneously the PDFs and the new physics signals, which can be done using our publicly released open-source tool SIM Unet.