NLO QCD corrections to full off-shell production of $t\bar{t}Z$ including leptonic decays

Abstract

Motivated by ongoing new physics searches in the top-quark sector at the Large Hadron Collider we report on the calculation of NLO QCD corrections to the Standard Model $pp\to t\bar{t}Z+X$ process in the tetra-lepton decay channel. This calculation is based on the matrix elements for the $e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }b\bar{b}{\tau }^{+}{\tau }^{-}$ final state and includes all resonant and non-resonant Feynman diagrams, interferences and off-shell effects of the top quark as well as the $W$ and $Z$ gauge bosons. Also incorporated are photon-induced contributions. As it is customary for such studies, we show theoretical predictions for both fixed and dynamical factorisation and renormalisation scale choices and different PDF sets. Furthermore, we study the main theoretical uncertainties that are associated with neglected higher-order terms in the perturbative expansion and with the parameterisation of the PDF sets. In order to investigate the size of off-shell effects and higher-order corrections in top-quark decays, we perform a second computation for this process, which is based on the narrow-width-approximation where the top quarks, $W$ and $Z$ gauge bosons are kept on-shell. Results are given for the integrated and differential fiducial cross sections for the LHC Run II center-of-mass energy of $13$ TeV.

33 pages, 12 figures, 7 tables, version to appear in JHEP

References in corpus (33)

• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Parton distributions for the LHC
• New parton distributions for collider physics
• LHAPDF6: parton density access in the LHC precision era
• Parton distributions in the LHC era: MMHT 2014 PDFs
• Reducing full one-loop amplitudes to scalar integrals at the integrand level
• Parton distributions from LHC, HERA, Tevatron and fixed target data: MSHT20 PDFs
• A standard format for Les Houches Event Files
• The Path to Proton Structure at One-Percent Accuracy
• OneLOop: for the evaluation of one-loop scalar functions
• Assault on the NLO Wishlist: pp -> tt bb
• On the Rational Terms of the one-loop amplitudes
• A Monte Carlo global analysis of the Standard Model Effective Field Theory: the top quark sector
• Helac-Phegas: a generator for all parton level processes
• t tbar W and t tbar Z Hadroproduction at NLO accuracy in QCD with Parton Shower and Hadronization effects
• Next-to-leading order QCD corrections to t-tbar-Z production at the LHC
• Polarizing the Dipoles
• Measurement of the $t\bar{t}Z$ and $t\bar{t}W$ cross sections in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Measurement of the Higgs boson production rate in association with top quarks in final states with electrons, muons, and hadronically decaying tau leptons at $\sqrt{s}=$ 13 TeV
• Associated production of a top quark pair with a heavy electroweak gauge boson at NLO+NNLL accuracy
• Off-shell Top Quarks with One Jet at the LHC: A comprehensive analysis at NLO QCD
• Matching the Nagy-Soper parton shower at next-to-leading order
• Multi-lepton signatures of vector-like leptons with flavor
• Kaleu: a general-purpose parton-level phase space generator
• The simplest of them all: $t\bar{t}{W}^{\pm }$ at NLO accuracy in QCD
• Model-Independent Production of a Top-Philic Resonance at the LHC
• PARNI for importance sampling and density estimation
• Model Independent Constraints Among the Wtb, Zbb, and Ztt Couplings
• Production and decay of the Higgs boson in association with top quarks
• Multi-lepton probes of new physics and lepton-universality in top-quark interactions
• Hadronic production of top-quark pairs in association with a pair of leptons in the POWHEG BOX framework
• The impact of top-quark modelling on the exclusion limits in $\mathbf{t}\bar{\mathbf{t}}+\text{DM}$ searches at the LHC
• Topping-up multilepton plus b-jets anomalies at the LHC with a $Z^{\prime }$ boson

Cited by in corpus (8)

• Les Houches 2021: Physics at TeV Colliders: Report on the Standard Model Precision Wishlist
• $\mathcal{C}\mathcal{P}$ structure of the top-quark Yukawa interaction: NLO QCD corrections and off-shell effects
• On two-body and three-body spin correlations in leptonic $t\bar{t}Z$ production and anomalous couplings at the LHC
• Four top final states with NLO accuracy in perturbative QCD: 4 lepton channel
• Les Houches 2023 -- Physics at TeV Colliders: Report on the Standard Model Precision Wishlist
• Four top final states with NLO accuracy in perturbative QCD: 3 lepton channel
• NLO QCD predictions for off-shell $t\bar{t}W$ production in association with a light jet at the LHC
• Observability of triple top quark signal at Future Hadron Colliders