Thursday 13 March 2025
For years, physicists have been working on a new way to understand the fundamental forces of nature. The latest development in this field is a series of calculations that aim to improve our understanding of the Drell-Yan process, which is the production of electroweak gauge bosons at hadron colliders.
To put it simply, the Drell-Yan process is a crucial aspect of particle physics, as it allows physicists to study the properties of quarks and gluons. However, these calculations are not easy to perform, especially when considering high-order corrections in perturbative Quantum Chromodynamics (pQCD).
A team of researchers has made significant progress in this area by developing new interpolation grids for the Drell-Yan process at next-to-next-to-leading order (NNLO). These grids enable fast evaluations of cross sections for different choices of parton distribution functions (PDFs) and scale settings, which is essential for determining PDFs.
The study begins with a brief overview of the current state of pQCD calculations. The authors highlight the challenges involved in performing high-order calculations and the need for efficient methods to re-evaluate predictions for different inputs.
The researchers then focus on their interpolation grids, which are generated using the parton-level Monte Carlo generator NNLOJET and the interpolation grid library PINEAPPL. These grids cover a wide range of Drell-Yan measurements performed at Tevatron and the LHC that commonly enter global PDF analyses.
One of the key findings of this study is the observation of accidental cancellations between partonic channels at NNLO, which are driven by strong correlations induced by the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution within the singlet sector. The authors also perform a detailed study of the K-factor approximation that was employed in previous PDF fits.
The results show that while few-% variations are found from the variation of PDF sets in the NNLO cross section, the K-factor is found to be very stable with only changes at the per-mille level. This suggests that the impact of the K-factor approximation on the resulting PDFs is minimal and well below the quoted uncertainties.
The study also highlights the potential for incorporating N3LO predictions into future PDF fits using approximate N3LO K-factors constructed from NNLO grids. This would allow physicists to further refine their understanding of the fundamental forces of nature.
Cite this article: “Advances in Understanding the Drell-Yan Process at Hadron Colliders”, The Science Archive, 2025.
Quantum Chromodynamics, Particle Physics, Drell-Yan Process, Electroweak Gauge Bosons, Hadron Colliders, Perturbative Quantum Chromodynamics, Parton Distribution Functions, Scale Settings, Interpolation Grids, Nnlo Calculations
