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Precise predictions for LHC using a GOLEM

T. Binoth, A. Guffanti, J. -Ph. Guillet, G. Heinrich, S. Karg, N. Kauer, P. Mertsch, T. Reiter, J. Reuter, G. Sanguinetti

TL;DR

The paper presents the GOLEM method for numerically stable, multi-leg one-loop amplitude calculations at the LHC, detailing symbolic and numerical form-factor reductions that avoid Gram determinant instabilities. It applies the approach to three LHC-relevant processes: gg->Z*Z*, ZZ+jet, and uu->ssbb, demonstrating both numerical stability and practical integration strategies. A key contribution is a local K-factor reweighting technique that enables LO event samples to approximate LO+virtual results without integrating the virtual corrections over phase space. The work advances the feasibility of precise NLO-like predictions for complex final states at TeV colliders, with potential impact on Higgs analyses and beyond-Standard Model backgrounds.

Abstract

In this talk we present recent next-to-leading order results relevant for LHC phenomenology obtained with the GOLEM method. After reviewing the status of this Feynman diagrammatic approach for multi-leg one-loop calculations we discuss three applications: the loop-induced process gg -> Z^*Z^* and the virtual corrections to the five and six point processes qq -> ZZg and u ubar -> s sbar c cbar. We demonstrate that our method leads to representations of such amplitudes which allow for efficient phase space integration. In this context we propose a reweighting technique of the leading order unweighted events by local K-factors.

Precise predictions for LHC using a GOLEM

TL;DR

The paper presents the GOLEM method for numerically stable, multi-leg one-loop amplitude calculations at the LHC, detailing symbolic and numerical form-factor reductions that avoid Gram determinant instabilities. It applies the approach to three LHC-relevant processes: gg->Z*Z*, ZZ+jet, and uu->ssbb, demonstrating both numerical stability and practical integration strategies. A key contribution is a local K-factor reweighting technique that enables LO event samples to approximate LO+virtual results without integrating the virtual corrections over phase space. The work advances the feasibility of precise NLO-like predictions for complex final states at TeV colliders, with potential impact on Higgs analyses and beyond-Standard Model backgrounds.

Abstract

In this talk we present recent next-to-leading order results relevant for LHC phenomenology obtained with the GOLEM method. After reviewing the status of this Feynman diagrammatic approach for multi-leg one-loop calculations we discuss three applications: the loop-induced process gg -> Z^*Z^* and the virtual corrections to the five and six point processes qq -> ZZg and u ubar -> s sbar c cbar. We demonstrate that our method leads to representations of such amplitudes which allow for efficient phase space integration. In this context we propose a reweighting technique of the leading order unweighted events by local K-factors.

Paper Structure

This paper contains 7 sections, 8 equations, 3 figures.

Table of Contents

  1. Introduction
  2. The GOLEM method
  3. Applications for LHC phenomenology
  4. The process $gg \to Z^*Z^*$
  5. The process $PP \to ZZ+$jet
  6. The process $u\bar{u}\to s\bar{s} b\bar{b}$
  7. Conclusion

Figures (3)

  • Figure 1: The invariant mass distribution of the 4 leptons including photonic contributions. Only a minimal cut $M_{\ell^+\ell^-}>5$ GeV is applied.
  • Figure 2: Scale dependence of the LO and virtual next-to-leading order corrections. The two curves in each plot show diagonal and anti-diagonal variation of the scales.
  • Figure 3: The $p_T$ and rapidity distribution of the leading jet. The full line is the LO, the dashed line is obtained by adding the UV/IR finite contribution of the virtual part of the NLO prediction, as defined in the text.