A Correction to this paper has been published: https://doi.org/10.1140/epjc/s10052-020-8227-9
Erratum to: Higgs boson production cross-section measurements and their EFT interpretation in the $$4\ell $$ 4 ℓ decay channel at $$\sqrt{s}=$$ s = 13 TeV with the ATLAS detector
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Erratum to: Search for the HH → b b ¯ b b ¯ $$ b\overline{b}b\overline{b} $$ process via vector-boson fusion production using proton-proton collisions at s $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector
One correction is noted for the paper.
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Tracking the outbreak: an optimized sequential adaptive strategy for Xylella fastidiosa delimiting surveys
Abstract
The EU plant health legislation enforces the implementation of intensive surveillance programs for quarantine pests. After an outbreak, surveys are implemented to delimit the extent of the infested zone and to manage disease control. Surveillance in agricultural and natural environments can be enhanced by increasing the survey efforts. Budget constraints often limit inspection and sampling intensities, thus making it necessary to adapt and optimize surveillance strategies. A sequential adaptive delimiting survey involving a three-phase and a two-phase design with increasing spatial resolution was developed and implemented for the Xylella fastidiosa demarcated area in Alicante, Spain. Inspection and sampling intensities were optimized using simulation-based methods. Sampling intensity thresholds were evaluated by quantifying their effect on the estimation of X. fastidiosa incidence. This strategy made it possible to sequence inspection and sampling taking into account increasing spatial resolutions, and to adapt the inspection and sampling intensities according to the information obtained in the previous, coarser, spatial resolution. The proposed strategy was able to efficiently delimit the extent of Xylella fastidiosa, while improving on the efficiency and maintaining the efficacy of the official survey campaign. From a methodological perspective, our approach provides new insights into alternative delimiting designs and new reference sampling intensity values.
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Search for charged Higgs bosons decaying into a top quark and a bottom quark at s $$ \sqrt{\mathrm{s}} $$ = 13 TeV with the ATLAS detector
Abstract
A search for charged Higgs bosons decaying into a top quark and a bottom quark is presented. The data analysed correspond to 139 fb−1 of proton-proton collisions at \( \sqrt{s} \) = 13 TeV, recorded with the ATLAS detector at the LHC. The production of a heavy charged Higgs boson in association with a top quark and a bottom quark, pp→ tbH+→ tbtb, is explored in the H+ mass range from 200 to 2000 GeV using final states with jets and one electron or muon. Events are categorised according to the multiplicity of jets and b-tagged jets, and multivariate analysis techniques are used to discriminate between signal and background events. No significant excess above the background-only hypothesis is observed and exclusion limits are derived for the production cross-section times branching ratio of a charged Higgs boson as a function of its mass; they range from 3.6 pb at 200 GeV to 0.036 pb at 2000 GeV at 95% confidence level. The results are interpreted in the hMSSM and \( {M}_h^{125} \) scenarios.
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Search for pair production of third-generation scalar leptoquarks decaying into a top quark and a τ-lepton in pp collisions at s $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector
Abstract
A search for pair production of third-generation scalar leptoquarks decaying into a top quark and a τ-lepton is presented. The search is based on a dataset of pp collisions at \( \sqrt{s} \) = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. Events are selected if they have one light lepton (electron or muon) and at least one hadronically decaying τ -lepton, or at least two light leptons. In addition, two or more jets, at least one of which must be identified as containing b-hadrons, are required. Six final states, defined by the multiplicity and flavour of lepton candidates, are considered in the analysis. Each of them is split into multiple event categories to simultaneously search for the signal and constrain several leading backgrounds. The signal-rich event categories require at least one hadronically decaying τ-lepton candidate and exploit the presence of energetic final-state objects, which is characteristic of signal events. No significant excess above the Standard Model expectation is observed in any of the considered event categories, and 95% CL upper limits are set on the production cross section as a function of the leptoquark mass, for different assumptions about the branching fractions into tτ and bν. Scalar leptoquarks decaying exclusively into tτ are excluded up to masses of 1.43 TeV while, for a branching fraction of 50% into tτ, the lower mass limit is 1.22 TeV.
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Muon reconstruction and identification efficiency in ATLAS using the full Run 2 pp collision data set at $$\sqrt{s}=13$$ s = 13 TeV
Abstract
This article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139 \(\hbox {fb}^{-1}\) of pp collision data at \(\sqrt{s}=13\) TeV collected between 2015 and 2018 during Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of \(Z\rightarrow \mu \mu \) and \(J/\psi \rightarrow \mu \mu \) decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of \(|\eta |<2.7\).
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Measurements of differential cross-sections in four-lepton events in 13 TeV proton-proton collisions with the ATLAS detector
Abstract
Measurements of four-lepton differential and integrated fiducial cross-sections in events with two same-flavour, opposite-charge electron or muon pairs are presented. The data correspond to 139 fb−1 of \( \sqrt{s} \) = 13 TeV proton-proton collisions, collected by the ATLAS detector during Run 2 of the Large Hadron Collider (2015–2018). The final state has contributions from a number of interesting Standard Model processes that dominate in different four-lepton invariant mass regions, including single Z boson production, Higgs boson production and on-shell ZZ production, with a complex mix of interference terms, and possible contributions from physics beyond the Standard Model. The differential cross-sections include the four-lepton invariant mass inclusively, in slices of other kinematic variables, and in different lepton flavour categories. Also measured are dilepton invariant masses, transverse momenta, and angular correlation variables, in four regions of four-lepton invariant mass, each dominated by different processes. The measurements are corrected for detector effects and are compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. The Z→ 4ℓ branching fraction is extracted, giving a value of (4.41 ± 0.30) × 10−6. Constraints on effective field theory parameters and a model based on a spontaneously broken B − L gauge symmetry are also evaluated. Further reinterpretations can be performed with the provided information.
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Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at $$\sqrt{s}=13$$ s = 13 with the ATLAS detector
Abstract
The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two W bosons, the lightest neutralinos (\(\tilde{\chi }^0_1\)), and quarks, are presented: the signal is characterised by the presence of a single charged lepton (\(e^{\pm }\) or \(\mu ^{\pm }\)) from a W boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb\(^{-1}\) of proton–proton collision data taken at a centre-of-mass energy \(\sqrt{s}=13\) delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2 (1.4 ) are excluded at 95% confidence level for a light \(\tilde{\chi }^0_1\).
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Search for supersymmetry in events with four or more charged leptons in 139 fb−1 of s $$ \sqrt{s} $$ = 13 TeV pp collisions with the ATLAS detector
Abstract
A search for supersymmetry in events with four or more charged leptons (electrons, muons and τ-leptons) is presented. The analysis uses a data sample corresponding to 139 fb−1 of proton-proton collisions delivered by the Large Hadron Collider at \( \sqrt{s} \) = 13 TeV and recorded by the ATLAS detector. Four-lepton signal regions with up to two hadronically decaying τ-leptons are designed to target several supersymmetric models, while a general five-lepton signal region targets any new physics phenomena leading to a final state with five charged leptons. Data yields are consistent with Standard Model expectations and results are used to set upper limits on contributions from processes beyond the Standard Model. Exclusion limits are set at the 95% confidence level in simplified models of general gauge-mediated supersymmetry, excluding higgsino masses up to 540 GeV. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to charged leptons, lower limits of 1.6 TeV, 1.2 TeV, and 2.5 TeV are placed on wino, slepton and gluino masses, respectively.
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Jet energy scale and resolution measured in proton–proton collisions at $$\sqrt{s}=13$$ s = 13 TeV with the ATLAS detector
Abstract
Jet energy scale and resolution measurements with their associated uncertainties are reported for jets using 36–81 fb\(^{-1}\) of proton–proton collision data with a centre-of-mass energy of \(\sqrt{s}=13\) \({\text {Te}}{\text {V}}\) collected by the ATLAS detector at the LHC. Jets are reconstructed using two different input types: topo-clusters formed from energy deposits in calorimeter cells, as well as an algorithmic combination of charged-particle tracks with those topo-clusters, referred to as the ATLAS particle-flow reconstruction method. The anti-\(k_t\) jet algorithm with radius parameter \(R=0.4\) is the primary jet definition used for both jet types. This result presents new jet energy scale and resolution measurements in the high pile-up conditions of late LHC Run 2 as well as a full calibration of particle-flow jets in ATLAS. Jets are initially calibrated using a sequence of simulation-based corrections. Next, several in situ techniques are employed to correct for differences between data and simulation and to measure the resolution of jets. The systematic uncertainties in the jet energy scale for central jets (\(|\eta |<1.2\)) vary from 1% for a wide range of high-\(p_{{\text {T}}}\) jets (\(250<p_{{\text {T}}} <2000~{\text {Ge}}{\text {V}}\)), to 5% at very low \(p_{{\text {T}}}\) (\(20~{\text {Ge}}{\text {V}}\)) and 3.5% at very high \(p_{{\text {T}}}\) (\(>2.5~{\text {Te}}{\text {V}}\)). The relative jet energy resolution is measured and ranges from (\(24 \pm 1.5\))% at 20 \({\text {Ge}}{\text {V}}\) to (\(6 \pm 0.5\))% at 300 \({\text {Ge}}{\text {V}}\).
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Measurement of single top-quark production in association with a W boson in the single-lepton channel at $$\sqrt{s} = 8\,\text {TeV}$$ s = 8 TeV with the ATLAS detector
Abstract
The production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at \(\sqrt{s} = 8\,\text {TeV}\). The dataset corresponds to an integrated luminosity of \(20.2\,\text {fb}^{-1}\), and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single-lepton channel. Events are selected by requiring one isolated lepton (electron or muon) and at least three jets. A neural network is trained to separate the tW signal from the dominant \(t{\bar{t}}\) background. The cross-section is extracted from a binned profile maximum-likelihood fit to a two-dimensional discriminant built from the neural-network output and the invariant mass of the hadronically decaying W boson. The measured cross-section is \(\sigma _{tW} = 26 \pm 7\,\text {pb}\), in good agreement with the Standard Model expectation.
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Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at $$\sqrt{s} = 13$$ s = 13 TeV with the ATLAS detector
Abstract
Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (\(t{\bar{t}}Z\)) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on \(\sqrt{s} = 13\) TeV proton–proton collision data with an integrated luminosity of 139 \(\hbox {fb}^{-1}\), recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be \(\sigma _{t{\bar{t}}Z} = 0.99 \pm 0.05\) (stat.) \(\pm \, 0.08\) (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the \(t{\bar{t}}Z\) system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a \(\chi ^{2}/\)ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.
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Search for dark matter produced in association with a single top quark in $$\sqrt{s}=13$$ s = 13 TeV $$pp$$ pp collisions with the ATLAS detector
Abstract
This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at \(\sqrt{s} = 13\) TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 \(\hbox {fb}^{-1}\). No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.
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Erratum to: Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at $$\sqrt{s}=13$$ s = 13 TeV with the ATLAS detector
A correction to this paper has been published: 10.1140/epjc/s10052-021-09344-w
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Erratum to: Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb−1 of Pb+Pb data with the ATLAS detector
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Erratum to: Measurement of hadronic event shapes in high-pT multijet final states at s $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector
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Erratum to: Search for single top-quark production via flavour-changing neutral currents at 8 TeV with the ATLAS detector
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Two-particle Bose–Einstein correlations in $${ pp }$$ pp collisions at $$\mathbf {\sqrt{s} = 13}$$ s = 13 TeV measured with the ATLAS detector at the LHC
Abstract
This paper presents studies of Bose–Einstein correlations (BEC) in proton–proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 \(\upmu \)b\(^{-1}\) and 8.4 nb\(^{-1}\), respectively. The BEC are measured for pairs of like-sign charged particles, each with \(|\eta | < 2.5\), for two kinematic ranges: the first with particle \(p_{\mathrm {T}} > 100\) MeV and the second with particle \(p_{\mathrm {T}} > 500\) MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair.
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Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at $$ \sqrt{s} $$ = 13 TeV with the ATLAS detector
Abstract
A measurement of the top-quark mass (mt) in the \( t\overline{t} \)→ lepton + jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass mℓμ of the lepton, ℓ (with ℓ = e, μ), from the W-boson decay and the muon, μ, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb−1 of \( \sqrt{s} \) = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 ± 0.39 (stat.) ± 0.66 (syst.) ± 0.25 (recoil) GeV, where the third uncertainty arises from changing the Pythia8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup.
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Erratum to: Search for exclusive Higgs and Z boson decays to ϕγ and ργ with the ATLAS detector
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