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State-of-the-art cross sections for $t\bar{t}H$: NNLO+NNLL+EW predictions

Anna Kulesza

TL;DR

The paper delivers the most precise SM prediction for the total cross section of $pp\\to t\\bar{t}H$ at the LHC by combining NNLO QCD corrections with approximate two-loop amplitudes and NNLL soft-gluon threshold resummation in both direct QCD and SCET frameworks, plus complete NLO EW corrections. A cross-validated uncertainty analysis shows scale dependencies are reduced when adding NNLL, and residual differences reflect subleading N^3LL effects. The main result is the cross section $\\sigma_{NNLO+NNLL+EW} = 592.1~\\text{fb}$ with a detailed error budget: $^{+1.5\\%}_{-2.2\\%}$ (scale), $\\pm 2.2\\%$ (PDF), $\\pm 1.7\\%$ (\\alpha_s), and $\\pm 0.9\\%$ (virt). These results sharpen the extraction of the top Yukawa coupling and CP structure and support precision SM tests and BSM searches.

Abstract

The most precise theoretical predictions for the total cross section for the associated production of a Higgs boson with a top-antitop quark pair at the LHC, first presented in \cite{Balsach:2025tth}, are reported. The calculation combines NNLO QCD corrections that include an approximation of the two-loop virtual contribution, with soft-gluon resummation at NNLL accuracy in two independent frameworks (SCET and direct QCD), and complete NLO electroweak corrections.

State-of-the-art cross sections for $t\bar{t}H$: NNLO+NNLL+EW predictions

TL;DR

The paper delivers the most precise SM prediction for the total cross section of at the LHC by combining NNLO QCD corrections with approximate two-loop amplitudes and NNLL soft-gluon threshold resummation in both direct QCD and SCET frameworks, plus complete NLO EW corrections. A cross-validated uncertainty analysis shows scale dependencies are reduced when adding NNLL, and residual differences reflect subleading N^3LL effects. The main result is the cross section with a detailed error budget: (scale), (PDF), (\\alpha_s), and (virt). These results sharpen the extraction of the top Yukawa coupling and CP structure and support precision SM tests and BSM searches.

Abstract

The most precise theoretical predictions for the total cross section for the associated production of a Higgs boson with a top-antitop quark pair at the LHC, first presented in \cite{Balsach:2025tth}, are reported. The calculation combines NNLO QCD corrections that include an approximation of the two-loop virtual contribution, with soft-gluon resummation at NNLL accuracy in two independent frameworks (SCET and direct QCD), and complete NLO electroweak corrections.
Paper Structure (4 sections, 1 equation, 1 figure)

This paper contains 4 sections, 1 equation, 1 figure.

Table of Contents

  1. Introduction
  2. NNLO QCD predictions
  3. NNLL threshold resummation
  4. NNLO+NNLL+EW numerical predictions

Figures (1)

  • Figure 1: Left: Comparison between NNLO+NNLL results in dQCD and SCET for three parametrically different choices of default scales. Right: Comparison of combined NNLO+NNLL results with NNLO for the same three scale choices. No EW corrections are included.