QCD Corrections to Hadronic $Wγ$ Production with Non-standard $WWγ$ Couplings

TL;DR

The paper computes hadronic Wγ production to O(αs) with general CP-conserving WWγ couplings, integrating W→ℓν decay in the narrow-width limit and employing a Monte Carlo framework to study diverse observables under realistic cuts. It finds that inclusive NLO QCD corrections are modest at the Tevatron but large at SSC/LHC, especially at high pT(γ), which reduces sensitivity to anomalous couplings; imposing a jet veto to isolate the Wγ+0 jet channel significantly mitigates these corrections and partially restores sensitivity. The work also demonstrates reduced factorization-scale dependence for exclusive 0-jet predictions and provides quantitative 1σ/2σ limits on anomalous couplings under various collider scenarios, emphasizing the practical utility of jet veto strategies. Overall, accurate QCD corrections and appropriate event selections are crucial for robust probes of the WWγ vertex at current and future hadron colliders.

Abstract

The process $p \pbar \rightarrow W^{\pm}γ+ X \rightarrow \ell^\pm νγ+ X$ is calculated to ${\cal O}(α_s)$ for general $CP$ conserving $WWγ$ couplings. At the Tevatron center of mass energy, the QCD corrections to $Wγ$ production are modest, and the Born and inclusive ${\cal O}(α_s)$ cross sections have similar sensitivities to the effects of anomalous couplings. At supercollider energies, the inclusive QCD corrections are large at high photon transverse momenta, reducing the sensitivity to non-standard $WWγ$ couplings by up to a factor~2. The size of the QCD corrections can be reduced significantly, and a large fraction of the sensitivity lost can be regained, if a jet veto is imposed.