Electroweak and QCD corrections to top-pair hadroproduction in association with heavy bosons

TL;DR

The paper addresses precise predictions for top-quark pair production in association with heavy SM bosons (ttH, ttZ, ttW) at current and future hadron colliders. It implements a mixed-coupling expansion to compute NLO electroweak corrections of order $α_S^2α^2$ and combines them with the dominant QCD corrections, while also including LO terms in $α_S α^2$ and $α_S^2 α$ to form a complete phenomenology. The calculations are automated in MadGraph5_aMC@NLO with QED subtraction and photon PDFs, and cross-checked with multiple schemes ($α(m_Z)$ and $G_μ$) and scale/PDF uncertainties. Key findings show large, energy-dependent NLO QCD corrections, non-negligible EW contributions—especially at high transverse momentum—and notable Heavy-Boson Radiation effects, underscoring the need for fully differential predictions in precision ttV studies.

Abstract

We compute the contribution of order $α_S^2α^2$ to the cross section of a top-antitop pair in association with at least one heavy Standard Model boson -- $Z$, $W^\pm$, and Higgs -- by including all effects of QCD, QED, and weak origin and by working in the automated MadGraph5_aMC@NLO framework. This next-to-leading order contribution is then combined with that of order $α_S^3α$, and with the two dominant lowest-order ones, $α_S^2α$ and $α_Sα^2$, to obtain phenomenological results relevant to a 8, 13, and 100~TeV $pp$ collider.

Figures (8)

• Figure 1: LO- and NLO-accurate results for $t\bar{t}H$ production at 13 TeV.
• Figure 2: Same as in fig. \ref{['fig:tth13-nocuts']}, with the cuts of eq. (\ref{['eq:boosted']}).
• Figure 3: Same as in fig. \ref{['fig:tth13-nocuts']}, for $t\bar{t}Z$ production.
• Figure 4: Same as in fig. \ref{['fig:tth13-cuts']}, for $t\bar{t}Z$ production.
• Figure 5: Same as in fig. \ref{['fig:tth13-nocuts']}, for $t\bar{t}W^+$ production.