Next-to-leading order QCD corrections to $W^+W^+$ and $W^-W^-$ production in association with two jets

TL;DR

The paper addresses same-sign $W$ boson pairs produced with two jets at the LHC by computing both electroweak-induced ($O(\alpha^6)$) and QCD-induced ($O(\alpha_s^2 \alpha^4)$) contributions and their interference, including off-shell $W$ effects. It presents a full LO analysis and NLO QCD corrections to the QCD-induced channels, implemented through two independent codes within the VBFNLO framework, with detailed treatment of virtual (up to six-point) and real emission using Catani-Seymour subtraction. The study analyzes the impact of VBF cuts on suppressing QCD backgrounds and validating the VBF approximation, and investigates scale choices, showing that a dynamic scale $\mu_0$ can fail at large jet separation unless replaced by $\mu'_0$ which accounts for $m_{jj}$. Interference can be sizable under inclusive cuts but is reduced under VBF selections, while NLO corrections markedly reduce theoretical uncertainties and refine differential distributions, providing a robust, publicly available tool for precision predictions of vector-boson scattering processes and related backgrounds.

Abstract

We present a study of $W^+W^+jj$ and $W^-W^-jj$ production including leptonic decays in hadron-hadron collisions. The full electroweak and QCD induced contributions and their interferences are calculated at leading order. We find that, for inclusive cuts, the interference effects can be large if the jets are produced with large transverse momentum where, however, the production rate is suppressed. We also discuss the vector-boson-fusion (VBF) cuts and show the validity of the VBF approximation. The NLO QCD corrections to the QCD-induced channels are also calculated. Compared to the previous calculation, we allow the intermediate $W$ bosons to be off-shell. For on-shell $W$ production, we obtain an excellent agreement with previous results. Our code will be publicly available as part of the parton level Monte Carlo program VBFNLO.

Figures (11)

• Figure 1: Representative tree-level Feynman diagrams of the QCD-induced mechanisms for the process $pp\rightarrow e^+\nu_e \mu^+ \nu_\mu~jj$.
• Figure 2: Diagram types contributing to the virtual amplitude.
• Figure 3: Contributions of the abelian boxline.
• Figure 4: Nonabelian boxline contributions. The dot indicates the additional position, where the external boson can be attached.
• Figure 5: Self-energy contributions to the amplitude.