Next-to-leading order QCD corrections to W+W+jj and W-W-jj production via weak-boson fusion

TL;DR

Problem: precise predictions for WBF WW jj production at the LHC are required to probe the electroweak sector and constrain new physics scenarios. Approach: the authors develop a fully flexible, parton-level Monte Carlo that computes NLO-QCD corrections for pp -> e^+ nu_e mu^+ nu_mu jj via weak-boson fusion, including leptonic decays and realistic WBF cuts, with robust validation. Findings: NLO-QCD corrections to integrated cross sections are modest (typically below 7%), and residual scale uncertainties are at the few-percent level; adopting a dynamical scale Q stabilizes differential distributions and yields K-factors near unity across key observables. Significance: the work provides reliable, precise predictions for WBF WW jj at the LHC and a versatile tool for experimental analyses of electroweak processes and potential new physics effects.

Abstract

We present a next-to-leading order QCD calculation for e+ nu_e mu+ nu_mu jj and e- nubar_e mu- nubar_mu jj production via weak boson fusion at a hadron collider in the form of a fully-flexible parton-level Monte Carlo program, which allows for the calculation of experimentally accessible observables within realistic selection cuts. The QCD corrections to the integrated cross sections are found to be modest, while the shapes of some kinematical distributions change appreciably compared to leading order. The residual scale uncertainties of the next-to-leading order results are at the few-percent level.

Figures (4)

• Figure 1: Feynman-graph topologies contributing to the Born process $uc\to d s e^+\nu_e\mu^+\nu_\mu$. Not shown are diagrams analogous to (a) and (d) with $W^+$ emission from the lower quark line. $V$ denotes a $Z$ boson or a photon.
• Figure 2: Dependence of the total WBF $pp\to e^+\nu_e\mu^+\nu_\mu jj$ cross section at the LHC on the factorization and renormalization scales for the two different choices of $\mu_0$: $\mu_0=m_W$ and $\mu_0=Q$. The NLO curves show $\sigma^\mathrm{cuts}$ as a function of the scale parameter $\xi$ for three different cases: $\mu_R=\mu_F=\xi\mu_0$ (solid red), $\mu_F=\xi\mu_0$ and $\mu_R=\mu_0$ (dot-dashed blue), $\mu_R=\xi\mu_0$ and $\mu_F=\mu_0$ (dashed green). The LO cross sections depend only on $\mu_F$ (dotted black).
• Figure 3: Rapidity distribution of the jet with the highest (a) and with the lowest (b) value of the absolute value of the rapidity $|y_j|$ in WBF $pp\to e^+\nu_e\mu^+\nu_\mu jj$ production at the LHC at LO (dashed black line) and NLO (solid red line).
• Figure 4: Invariant mass distribution of the tagging jets in WBF $pp\to e^+\nu_e\mu^+\nu_\mu jj$ production at the LHC for two different choices of $\mu_0$ [panels (a) and (b)] at LO (dashed) and NLO (solid). Their ratios, the $K$ factors as defined in Eq. (\ref{['eq:kfac']}), are displayed for $\mu_0 = m_W$ in panel (c) and for $\mu_0 = Q$ in panel (d).