Subleading EW corrections and spin-correlation effects in $$t\bar{t}W$$ multi-lepton signatures

Frederix, Rikkert; Tsinikos, Ioannis

doi:10.1140/epjc/s10052-020-8388-6

Cited by 42 publications

(59 citation statements)

References 27 publications

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“…The irreducible background is evaluated using MC simulation normalised to the SM cross sections, except tt W +jets for which the normalisation is corrected using data in a dedicated control region. The different treatment for the tt W +jets background is motivated by theoretical studies [69] showing that electroweak corrections not included in the simulation have a significant effect as well as by the large tt W +jets background normalisation factor found in recent measurements in similar phase space [70].…”

Section: Background Estimationmentioning

confidence: 99%

Evidence for $$t\bar{t}t\bar{t}$$ production in the multilepton final state in proton–proton collisions at $$\sqrt{s}=13$$ $$\text {TeV}$$ with the ATLAS detector

Aad¹,

Abbott²,

Abbott³

et al. 2020

Eur. Phys. J. C

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A search is presented for four-top-quark production using an integrated luminosity of 139 fb$$^{-1}$$ - 1 of proton–proton collision data at a centre-of-mass energy of $$13~\text {TeV}$$ 13 TeV collected by the ATLAS detector at the LHC. Events are selected if they contain a same-sign lepton pair or at least three leptons (electrons or muons). Jet multiplicity, jet flavour and event kinematics are used to separate signal from the background through a multivariate discriminant, and dedicated control regions are used to constrain the dominant backgrounds. The four-top-quark production cross section is measured to be $$24^{+7}_{-6}$$ 24 - 6 + 7 fb. This corresponds to an observed (expected) significance with respect to the background-only hypothesis of 4.3 (2.4) standard deviations and provides evidence for this process.

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Section: Background Estimationmentioning

confidence: 99%

Evidence for $$t\bar{t}t\bar{t}$$ production in the multilepton final state in proton–proton collisions at $$\sqrt{s}=13$$ $$\text {TeV}$$ with the ATLAS detector

Aad¹,

Abbott²,

Abbott³

et al. 2020

Eur. Phys. J. C

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“…An NLO QCD analysis including partonshower matching with the focus of effects of spin correlations and subleading electroweak corrections on asymmetries was presented in ref. [35]. The first computation of NLO QCD corrections including all off-shell effects and spin correlations appeared very recently [36] for hadronic collisions at 13 TeV CM energy in the three-charged-leptons decay channel.…”

Section: Jhep11(2020)069mentioning

confidence: 99%

“…More refined techniques have been investigated to complement the inclusive results with spin correlations and off-shell effects, without computing the full off-shell process, e.g. using the narrow-width approximation [26,35]. Such approximations help in assessing the importance of resonance structures as well as in validating parts of the full calculation.…”

Section: Double-pole Approximationmentioning

confidence: 99%

NLO QCD corrections to off-shell $$ \mathrm{t}\overline{\mathrm{t}}{\mathrm{W}}^{\pm } $$ production at the LHC

Denner

Pelliccioli

2020

J. High Energ. Phys.

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We present results of a computation of NLO QCD corrections to the production of an off-shell top-antitop pair in association with an off-shell W+ boson in proton-proton collisions. As the calculation is based on the full matrix elements for the process $$ \mathrm{pp}\to {\mathrm{e}}^{+}{v}_{\mathrm{e}}{\mu}^{-}{\overline{v}}_{\mu }{\tau}^{+}{v}_{\tau}\mathrm{b}\overline{\mathrm{b}} $$ pp → e + v e μ − v ¯ μ τ + v τ b b ¯ , all off-shell, spin-correlation, and interference effects are included. The NLO QCD corrections are about 20% for the integrated cross-section. Using a dynamical scale, the corrections to most distributions are at the same level, while some distributions show much larger K-factors in suppressed regions of phase space. We have performed a second calculation based on a double-pole approximation. While the corresponding results agree with the full calculation within few per cent for integrated cross-sections, the discrepancy can reach 10% and more in regions of phase space that are not dominated by top-antitop production. As a consequence, on-shell calculations should only be trusted to this level of accuracy.

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“…• The O(α s α 3 ) ttW j(EW) contribution to ttW + jets is important and should be consistently included at the differential level, as originally pointed out in [12] and later analyzed in depth in [54,59].…”

Section: Jhep02(2021)043mentioning

confidence: 99%

“…The discrepancies are mild, yet their somewhat coherent structure hints that they may not be due to mere statistical fluctuations. 5 Recent theoretical studies have focused on pushing the SM predictions to higher accuracy, especially for ttW [57][58][59][60][61][62][63], which however still exhibits the strongest disagreement between theory and experiment. For the time being, a complete NNLO QCD calculation remains out of reach.…”

mentioning

confidence: 99%

The present and future of four top operators

Banelli

Salvioni

Serra

et al. 2021

J. High Energ. Phys.

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We study the phenomenology of a strongly-interacting top quark at future hadron and lepton colliders, showing that the characteristic four-top contact operators give rise to the most significant effects. We demonstrate the extraordinary potential of a 100 TeV proton-proton collider to directly test such non-standard interactions in four-top production, a process that we thoroughly analyze in the same-sign dilepton and trilepton channels, and explore in the fully hadronic channel. Furthermore, high-energy electron-positron colliders, such as CLIC or the ILC, are shown to exhibit an indirect yet remarkable sensitivity to four-top operators, since these constitute, via renormalization group evolution, the leading new-physics deformations in top-quark pair production. We investigate the impact of our results on the parameter space of composite Higgs models with a strongly-coupled (right-handed) top quark, finding that four-top probes provide the best sensitivity on the compositeness scale at the future energy frontier. In addition, we investigate mild yet persisting LHC excesses in multilepton plus jets final states, showing that they can be consistently described in the effective field theory of such a new-physics scenario.

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Subleading EW corrections and spin-correlation effects in $$t\bar{t}W$$ multi-lepton signatures

Cited by 42 publications

References 27 publications

Evidence for $$t\bar{t}t\bar{t}$$ production in the multilepton final state in proton–proton collisions at $$\sqrt{s}=13$$ $$\text {TeV}$$ with the ATLAS detector

Evidence for $$t\bar{t}t\bar{t}$$ production in the multilepton final state in proton–proton collisions at $$\sqrt{s}=13$$ $$\text {TeV}$$ with the ATLAS detector

NLO QCD corrections to off-shell $$ \mathrm{t}\overline{\mathrm{t}}{\mathrm{W}}^{\pm } $$ production at the LHC

The present and future of four top operators

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