QCD corrections to non-standard WZ+jet production with leptonic decays at the LHC

TL;DR

Problem: quantify how anomalous $WW\gamma$ and $WWZ$ couplings affect $pp\to WZ+\text{jet}$ at the LHC with leptonic decays, at NLO QCD. Approach: a flexible Monte Carlo in the VBFNLO framework computes NLO QCD corrections including dimension-6 operators with dipole form factors and full leptonic decays, constrained by LEP data, with a dipole scale $\Lambda=2~\mathrm{TeV}$; infrared singularities are handled via Catani–Seymour subtraction. Findings: inclusive cross sections remain largely insensitive to the anomalous couplings within the residual scale uncertainty, while high-$p_T$ regions and specific kinematic selections reveal deviations in differential distributions; NLO corrections reduce sensitivity in inclusive observables, but targeted cuts (e.g., back-to-back $WZ$ and large lepton separations) can enhance it. Significance: provides a precise framework for interpreting LHC data on anomalous gauge couplings, emphasizes the necessity of NLO accuracy and careful event selection, and offers a publicly available Monte Carlo tool for diboson plus jet studies.

Abstract

We discuss the impact of anomalous WW$γ$ and WWZ couplings on WZ+jet production at next-to-leading order QCD, including full leptonic decays of the electroweak gauge bosons. While the inclusive hadronic cross sections do not exhibit any particular sensitivity to anomalous couplings once the residual QCD scale uncertainties are taken into account, the transverse momentum distributions show substantial deviations from the Standard Model, provided that the anomalous vertices are probed at large enough momentum transfers.

Figures (8)

• Figure 1: Scale dependence of the SM cross section at LO and NLO for the set up described in Sec. \ref{['sec:res']}. In addition to the fixed-scale variation, we also plot the variation for renormalization and factorization scales chosen to be the maximum transverse momentum of the charged leptons. Varying $\mu$ by a factor two around $\xi=1$ reduces the uncertainties from $24\%$ ($23\%$) at LO to $9\%$ ($10\%$) at NLO for $\mu=\xi\times 100~{\rm{GeV}}$ ($\mu=\xi\max p_T^\ell$).
• Figure 2: Total LO cross section contours in fb for $W^-Z$+jet production for the cut and parameter choices as described in the text. We use a fixed-scale choice $\mu_R=\mu_F=100~{\rm{GeV}}$. Additionally, we choose $\Delta g^{Z,0}_1=0$.
• Figure 3: Total NLO cross section contours in fb for $W^-Z+{\rm{jet}}$ production analogous to Fig. \ref{['fig:lototalxsecs']}.
• Figure 4: Total $K$ factor contours for $W^-Z+{\rm{jet}}$ production analogous to Fig. \ref{['fig:lototalxsecs']}.
• Figure 5: Total NLO cross section contours in fb for $W^-Z+{\rm{jet}}$ production for the cut and parameter choices as described in the text, with the additional requirement of Eq. (\ref{['eq:ellcriter']}). We again choose $\Delta g^{Z,0}_1=0$. We choose $\mu_R=\mu_F=\max p_T^\ell$.