Electroweak Radiative Corrections to W Boson Production in Hadronic Collisions

TL;DR

This work delivers a complete O(α) electroweak correction calculation for W production in hadronic collisions, including initial-, final-, and interference-effects, and provides a gauge-invariant QED-like decomposition plus a modified weak component. It treats collinear and infrared singularities via mass factorization into QED PDFs in DIS and MSbar schemes, enabling realistic Monte Carlo analyses that incorporate detector effects and lepton-identification criteria. Numerically, final-state photon radiation dominates the EW corrections to MT and pT(ℓ) distributions, while initial-state corrections are comparatively small after factorization; lepton-ID procedures substantially affect electron-channel logs, whereas muon-channel corrections can remain significant in some regions. The results show non-negligible shifts in W-boson observables and the W/Z cross-section ratio, underscoring the need to include complete EW corrections for precision W-marity measurements and for robust tests of the Standard Model at current and future colliders.

Abstract

The O(α) electroweak radiative corrections to the process pp, ppbar\to W \to\ell^\pmν(\ell=e,μ) are calculated. The O(α) corrections can be decomposed into separately gauge invariant contributions to the W boson production and decay processes. Factorizing the collinear singularity associated with initial state photon radiation into the parton distribution functions, we find that initial state corrections have a significantly smaller effect than final state radiative corrections. We study in detail the effect of electroweak radiative corrections on a number of interesting observables: the W transverse mass distribution, the W to Z transverse mass ratio, the charge asymmetry of leptons in W\to\ellνdecays, as well as the W production cross section and the W to Z cross section ratio. We also investigate how experimental lepton identification requirements change the effect of the electroweak corrections.

Figures (13)

• Figure 1: The Feynman diagrams contributing to $W$ boson production at ${\cal O}(\alpha^3)$ ($\Phi^+$: Higgs -- ghost field, $u^+,u^{\gamma}$: Faddeev-Popov-ghost fields; the non-photonic contribution to the $W$ self energy insertion is symbolized by the shaded loop). An explicit representation of the non-photonic contribution to the $W$ self energy insertion can be found in Ref. [\ref{['fort']}].
• Figure 2: The splitting of the initial and final state fermions $i(p_i)\rightarrow h(p_h)+\gamma$ and $h(p_h)\rightarrow f(p_f)+\gamma$ in the collinear region. The hard momentum $p_h$ represents the amount of the parent momentum $p_{i,f}$ after (before) the emission of a collinear photon.
• Figure 3: The QED one-loop corrections in deep inelastic lepton -- nucleon scattering.
• Figure 4: The QED-like initial state corrections to the $p\bar{p}\to\ell^+\nu(\gamma)$, ($\ell=e,\,\mu$) cross section for ${\sqrt{s}=1.8}$ TeV as a function of a) $\delta_s$ for $\delta_\theta=0.001$, and b) $\delta_\theta$ for $\delta_s=0.01$. Shown are $\sigma(2\to 2) -\sigma({\rm Born})$, $\sigma(2\to 3)$, and $\sigma(2\to 2)+\sigma(2\to 3)-\sigma({\rm Born})$. The cuts imposed are listed in Eqs. (\ref{['eq:lepcut']}) and (\ref{['eq:ptmisscut']}). The energy and momentum resolutions used are described in the text.
• Figure 5: The QED-like final state corrections to the cross section a) $\sigma(p\bar{p}\to e^+\nu(\gamma))$ and b) $\sigma(p\bar{p}\to\mu^+\nu(\gamma))$ for ${\sqrt{s}=1.8}$ TeV as a function of $\delta_s$. Shown are $\sigma(2\to 2) -\sigma({\rm Born})$, $\sigma(2\to 3)$, and $\sigma(2\to 2)+\sigma(2\to 3)-\sigma({\rm Born})$. The cuts imposed are listed in Eqs. (\ref{['eq:lepcut']}) and (\ref{['eq:ptmisscut']}). The energy and momentum resolutions used are described in the text.