Off-shell $t\bar{t}b\bar{b}$ production at the LHC: QCD corrections, theory uncertainties and $b$-jet definitions

TL;DR

This paper provides precise NLO QCD predictions for off-shell top-antitop-bottom-antibottom production at the LHC, including all relevant effects and uncertainties, crucial for accurate background modeling in top physics analyses.

Contribution

It offers the first comprehensive NLO QCD calculation of off-shell $tar{t}bar{b}$ production with full resonance, interference, and finite-width effects at the LHC.

Findings

QCD corrections significantly affect cross sections and distributions.

Theoretical uncertainties are quantified from scale and PDF variations.

Initial-state $b$ quark contributions are evaluated and found to be relevant.

Abstract

We present state-of-the-art predictions for off-shell $t\bar{t}b\bar{b}$ production with di-lepton decays at the LHC with $\sqrt{s}=13$ TeV. Results are accurate at NLO in QCD and include all resonant and non-resonant diagrams, interferences and finite-width effects for top quarks and $W$ bosons. We discuss the impact of QCD corrections and assess theoretical uncertainties from scale and PDF dependence at the integrated and differential level. Additionally we investigate the size of contributions induced by initial-state $b$ quarks to the NLO cross section.