Parton distributions in the SMEFT from high-energy Drell-Yan tails

Understand

The high-energy tails of charged- and neutral-current Drell-Yan processes provide important constraints on the light quark and anti-quark parton distribution functions (PDFs) in the large-x region.

• At the same time, short-distance new physics effects such as those encoded by the Standard Model Effective Field Theory (SMEFT) would induce smooth distortions to the same high-energy Drell-Yan tails.
• In this work, we assess for the first time the interplay between PDFs and EFT effects for high-mass Drell-Yan processes at the LHC and quantify the impact that the consistent joint determination of PDFs and Wilson coefficients has on the bounds derived for the latter.
• We consider two well-motivated new physics scenarios: $1)$ electroweak oblique corrections $(\hat W, \hat Y)$ and $2)$ four-fermion interactions potentially related to the LHCb anomalies in $R(K^{(*)})$.