CPT Colloquia

Hide and seek: how PDFs can conceal new physics

by Maria Ubiali

The interpretation of 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 a new framework that sheds light on the interplay between the parametrization of the proton structure and the parametrization of new physics is presented, according to two complementary approaches.
On the one hand, a new framework is introduced, which allows the determination of PDFs alongside the Wilson coefficients of a model-independent EFT. On the other hand, 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 is presented. A scenario in which the PDFs may completely absorb such signs of new physics is showcased. Strategies to single out the effects in this scenario, and disentangle the inconsistencies that stem from them are discussed.