O(\alpha_s\alpha) corrections to Drell-Yan processes in the resonance region

TL;DR

This paper discusses high-precision theoretical predictions for Drell-Yan W/Z boson production near resonance, focusing on mixed electroweak and QCD corrections at order alpha_s alpha, and confirms the negligible impact of non-factorizable contributions.

Contribution

It introduces a systematic expansion around the resonance pole for mixed electroweak and QCD corrections, providing first estimates of dominant factorizable O(alpha_s alpha) effects.

Findings

Non-factorizable corrections are phenomenologically negligible.

Factorizable corrections at O(alpha_s alpha) differ significantly from simple product approximations.

Validation of the resonance pole expansion for electroweak corrections.

Abstract

Drell-Yan-like W-boson and Z-boson production in the resonance region allows for some high-precision measurements that are crucial to carry experimental tests of the Standard Model to the extremes, such as the determinations of the W-boson mass and the effective weak mixing angle. We describe how the Standard Model prediction can be successfully performed in terms of a consistent expansion about the resonance pole, which classifies the corrections in terms of factorizable and non-factorizable contributions. The former can be attributed to the W/Z production and decay subprocesses individually, while the latter link production and decay by soft-photon exchange. At next-to-leading order we compare the full electroweak corrections with the pole-expanded approximations, confirming the validity of the approximation. At O(\alpha_s\alpha), we describe the concept of the expansion and report on results on the non-factorizable contributions, which turn out to be phenomenologically negligible. Moreover, we present first (preliminary) results on the dominant factorizable O(\alpha_s\alpha) corrections, which originate from the interplay of initial-state QCD and final-state electroweak corrections. Numerically those corrections significantly differ from a mere product of the two next-to-leading-order correction factors.