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NLO QCD Predictions for W+3 jets

C. F. Berger, Z. Bern, L. J. Dixon, F. Febres Cordero, D. Forde, T. Gleisberg, H. Ita, D. A. Kosower, D. Maitre

TL;DR

This work delivers the first complete NLO QCD predictions for $W$+$3$ jets at hadron colliders by combining $BlackHat$ for one-loop virtual amplitudes with $Sherpa$ for real emissions, spanning both the Tevatron and the LHC. The study shows that NLO predictions reduce scale uncertainties and provide more reliable differential distributions than LO, with the $H_T$-based scale $\hat{H}_T$ emerging as a robust choice for multi-jet observables. Comparisons to Tevatron data (e.g., $E_T$ of the third jet and dijet masses) demonstrate good agreement within uncertainties when using consistent jet definitions (SISCONE) and modern PDFs. The results have practical impact on background modeling for top-quark analyses and new-physics searches, and inform scale-setting strategies for complex multi-jet processes at the LHC.

Abstract

In this contribution we present results from the NLO computation of the production of a $W$ boson in association with three jets in hadronic collisions. The results are obtained by combining two programs: {\tt BlackHat} for the virtual one-loop matrix elements and {\tt Sherpa} for the real-emission contributions. We present results for the Tevatron and the LHC, and address the issue of the choice of a common factorization and renormalization scale for this process.

NLO QCD Predictions for W+3 jets

TL;DR

This work delivers the first complete NLO QCD predictions for + jets at hadron colliders by combining for one-loop virtual amplitudes with for real emissions, spanning both the Tevatron and the LHC. The study shows that NLO predictions reduce scale uncertainties and provide more reliable differential distributions than LO, with the -based scale emerging as a robust choice for multi-jet observables. Comparisons to Tevatron data (e.g., of the third jet and dijet masses) demonstrate good agreement within uncertainties when using consistent jet definitions (SISCONE) and modern PDFs. The results have practical impact on background modeling for top-quark analyses and new-physics searches, and inform scale-setting strategies for complex multi-jet processes at the LHC.

Abstract

In this contribution we present results from the NLO computation of the production of a boson in association with three jets in hadronic collisions. The results are obtained by combining two programs: {\tt BlackHat} for the virtual one-loop matrix elements and {\tt Sherpa} for the real-emission contributions. We present results for the Tevatron and the LHC, and address the issue of the choice of a common factorization and renormalization scale for this process.

Paper Structure

This paper contains 5 sections, 4 figures.

Table of Contents

  1. Introduction
  2. Tevatron Results
  3. Scale choices
  4. LHC results
  5. Conclusion

Figures (4)

  • Figure 1: Left panel: $E_T$ distribution of the third jet at the Tevatron. Right panel: dijet mass distributions. In both plots the LO and NLO results are represented by the blue and black lines, respectively. The (red) data points in the left panel show the $E_T$ distribution measured by CDF WCDF, including experimental errors. The lower panels show the data and the LO results normalized by the NLO result.
  • Figure 2: Different kinematic configurations for $W+3$ jets: in (a) the $W$ boson recoils against the three jets; in (b) the $W$ is relatively soft compared to the jets.
  • Figure 3: Comparison between two scale choices for the jet angular separation $\Delta R_{12}$ (left) and dijet mass $M_{12}$ (right) for the two hardest jets. The red line represents the choice $\mu=M_W^T$ and the black line $\mu=\hat{H}_T$.
  • Figure 4: The left panel shows the $E_T$ distribution of the second hardest jet at the LHC, while the right panel shows the third jet $E_T$. In both graphs, the LO and NLO results are represented by the blue (dashed) and black lines respectively. The lower panel shows the LO and NLO scale variation bands, normalized by the central NLO result.