Date

Measurements of differential cross sections of top quark pair production in association with jets in ${pp}$ collisions at $\sqrt{s}=13$ TeV using the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 10 (2018) 159, 2018.
Inspire Record 1656578 DOI 10.17182/hepdata.81950

Measurements of differential cross sections of top quark pair production in association with jets by the ATLAS experiment at the LHC are presented. The measurements are performed as functions of the top quark transverse momentum, the transverse momentum of the top quark-antitop quark system and the out-of-plane transverse momentum using data from $pp$ collisions at $\sqrt{s}=13$ TeV collected by the ATLAS detector at the LHC in 2015 and corresponding to an integrated luminosity of 3.2 fb$^{-1}$. The top quark pair events are selected in the lepton (electron or muon) + jets channel. The measured cross sections, which are compared to several predictions, allow a detailed study of top quark production.

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Systematic uncertanties for the absolute differential cross-section at particle-level for |$p_{out}^{t\bar{t}}$| in the 4-jet exclusive configuration. Note that the values shown here are obtained by propagating the individual uncertainties to the measured cross-sections, while the covariance matrices are evaluated using pseudo-experiments as described in the text.

Systematic uncertanties for the relative differential cross-section at particle-level for |$p_{out}^{t\bar{t}}$| in the 4-jet exclusive configuration. Note that the values shown here are obtained by propagating the individual uncertainties to the measured cross-sections, while the covariance matrices are evaluated using pseudo-experiments as described in the text.

Systematic uncertanties for the absolute differential cross-section at particle-level for $p_{T}^{t,had}$ in the 4-jet exclusive configuration. Note that the values shown here are obtained by propagating the individual uncertainties to the measured cross-sections, while the covariance matrices are evaluated using pseudo-experiments as described in the text.

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Measurements of Lund subjet multiplicities in 13 TeV proton-proton collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
Phys.Lett.B 859 (2024) 139090, 2024.
Inspire Record 2759899 DOI 10.17182/hepdata.138878

This Letter presents a differential cross-section measurement of Lund subjet multiplicities, suitable for testing current and future parton shower Monte Carlo algorithms. This measurement is made in dijet events in 140 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collision data collected with the ATLAS detector at CERN's Large Hadron Collider. The data are unfolded to account for acceptance and detector-related effects, and are then compared with several Monte Carlo models and to recent resummed analytical calculations. The experimental precision achieved in the measurement allows tests of higher-order effects in QCD predictions. Most predictions fail to accurately describe the measured data, particularly at large values of jet transverse momentum accessible at the Large Hadron Collider, indicating the measurement's utility as an input to future parton shower developments and other studies probing fundamental properties of QCD and the production of hadronic final states up to the TeV-scale.

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$N_{Lund}, k_t \geq 0.5~\text{GeV}$, All $p_T$ bins, Central $\eta$

$N_{Lund}, k_t \geq 0.5~\text{GeV}$, All $p_T$ bins, Forward $\eta$

$N_{Lund}, k_t \geq 0.5~\text{GeV}$, $300~\text{GeV} \leq p_T < 500~\text{GeV}$, Inclusive $\eta$

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Measurement of $ZZ$ production cross-sections in the four-lepton final state in $pp$ collisions at $\sqrt{s}=13.6$ TeV with the ATLAS experiment

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Lett.B 855 (2024) 138764, 2024.
Inspire Record 2723369 DOI 10.17182/hepdata.144768

This paper reports cross-section measurements of $ZZ$ production in $pp$ collisions at $\sqrt{s}=13.6$ TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb$^-1$. Events in the $ZZ\rightarrow4\ell$ ($\ell = e$, $\mu$) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66 $< m_Z <$ 116 GeV for both $Z$ bosons, yielding $16.8 \pm 1.1$ pb. The results are well described by the Standard Model predictions.

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The measured differential cross-sections compared to the predictions in the $m_{4\ell}$ bins

The measured differential cross-sections compared to the predictions in the $p_T^{4\ell}$ bins


Measurement of top-quark pair production in association with charm quarks in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
Phys.Lett.B 860 (2025) 139177, 2025.
Inspire Record 2829504 DOI 10.17182/hepdata.154444

Inclusive cross-sections for top-quark pair production in association with charm quarks are measured with proton-proton collision data at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 140 fb$^{-1}$, collected with the ATLAS experiment at the LHC between 2015 and 2018. The measurements are performed by requiring one or two charged leptons (electrons and muons), two $b$-tagged jets, and at least one additional jet in the final state. A custom flavor-tagging algorithm is employed for the simultaneous identification of $b$-jets and $c$-jets. In a fiducial phase space that replicates the acceptance of the ATLAS detector, the cross-sections for $t\bar{t}+ {\geq} 2c$ and $t\bar{t}+1c$ production are measured to be $1.28^{+0.27}_{-0.24}\;\text{pb}$ and $6.4^{+1.0}_{-0.9}\;\text{pb}$, respectively. The measurements are primarily limited by uncertainties in the modeling of inclusive $t\bar{t}$ and $t\bar{t}+b\bar{b}$ production, in the calibration of the flavor-tagging algorithm, and by data statistics. Cross-section predictions from various $t\bar{t}$ simulations are largely consistent with the measured cross-section values, though all underpredict the observed values by 0.5 to 2.0 standard deviations. In a phase-space volume without requirements on the $t\bar{t}$ decay products and the jet multiplicity, the cross-section ratios of $t\bar{t}+ {\geq} 2c$ and $t\bar{t}+1c$ to total $t\bar{t}+\text{jets}$ production are determined to be $(1.23 \pm 0.25) \%$ and $(8.8 \pm 1.3) \%$.

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Measured cross-section values in the fiducial phase space and inclusive volume for the various $t\bar{t}+jets$ categories.

Post-fit agreement between data and MC prediction for $SR_{\mathrm{loose}}^{1\ell5j}$ signal region, which uses the invariant mass of the two geometrically closest c-tagged jets, $m_{\mathit{cc}}^{\mathrm{min}\Delta R}$, as an observable. The hatched uncertainty bands include all uncertainties and their correlations. The last bins contain overflow events. "Other Top" includes single-top-quark production and associated production of $t\bar{t}$ and single top quarks with bosons. "Non-Top" includes W+jets, Z+jets, and diboson processes.

Post-fit agreement between data and MC prediction for the $SR_{\mathrm{tight}}^{1\ell5j}$ signal region, which uses the invariant mass of the two geometrically closest jets tagged with c@11%, $m_{\mathit{cc}}^{\mathrm{min}\Delta R}$, as an observable. The hatched uncertainty bands include all uncertainties and their correlations. The last bins contain overflow events. "Other Top" includes single-top-quark production and associated production of $t\bar{t}$ and single top quarks with bosons. "Non-Top" includes W+jets, Z+jets, and diboson processes.

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Search for Higgs boson decays into a $Z$ boson and a light hadronically decaying resonance in 140 fb$^{-1}$ of 13 TeV $p$$p$ collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
CERN-EP-2024-261, 2024.
Inspire Record 2851948 DOI 10.17182/hepdata.153859

A search for decays of the Higgs boson into a $Z$ boson and a light resonance, with a mass of 0.5-3.5 GeV, is performed using the full 140 fb$^{-1}$ dataset of 13 TeV proton-proton collisions recorded by the ATLAS detector during Run~2 of the LHC. Leptonic decays of the $Z$ boson and hadronic decays of the light resonance are considered. The resonance can be interpreted as a $J/\psi$ or $\eta_c$ meson, an axion-like particle, or a light pseudoscalar in two-Higgs-doublet models. Due to its low mass, it would be produced with high boost and reconstructed as a single small-radius jet of hadrons. A neural network is used to correct the Monte Carlo simulation of the background in a data-driven way. Two additional neural networks are used to distinguish signal from background. A binned profile-likelihood fit is performed on the final-state invariant mass distribution. No significant excess of events relative to the expected background is observed, and upper limits at 95% confidence level are set on the Higgs boson's branching fraction to a $Z$ boson and a light resonance. The exclusion limit is 10% for the lower masses, and increases for higher masses. Upper limits on the effective coupling $C^\text{eff}_{ZH}/\Lambda$ of an axion-like particle to a Higgs boson and $Z$ boson are also set at 95% confidence level, and range from 0.9 to 2 TeV$^{-1}$.

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The angularity, for data, background (pre- and post-reweighting) and three $H\rightarrow Za$ signal hypotheses (for $a\rightarrow q\bar{q}/gg$ inclusively). Events are required to pass the complete event selection but not the classification NN requirement. The background normalization is set equal to that of the data for events passing the preselection and being in the $m_{\ell\ell j}$ 100-180 GeV region. The signal normalization assumes the SM Higgs boson inclusive production cross-section, $\mathcal{B}(H\to Za)=100\%$, and it is scaled up by a factor of 100. The error bars (hatched regions) represent the data (MC) sample's statistical uncertainty in the histograms and the ratio plots. Vertical arrows indicate data points that fall outside the displayed $y$-axis range.

The modified energy correlation function, for data, background (pre- and post-reweighting) and three $H\rightarrow Za$ signal hypotheses (for $a\rightarrow q\bar{q}/gg$ inclusively). Events are required to pass the complete event selection but not the classification NN requirement. The background normalization is set equal to that of the data for events passing the preselection and being in the $m_{\ell\ell j}$ 100-180 GeV region. The signal normalization assumes the SM Higgs boson inclusive production cross-section, $\mathcal{B}(H\to Za)=100\%$, and it is scaled up by a factor of 100. The error bars (hatched regions) represent the data (MC) sample's statistical uncertainty in the histograms and the ratio plots. Vertical arrows indicate data points that fall outside the displayed $y$-axis range.

$Z$ boson transverse momentum, for data, background (pre- and post-reweighting) and three $H\rightarrow Za$ signal hypotheses (for $a\rightarrow q\bar{q}/gg$ inclusively). Events are required to pass the complete event selection but not the classification NN requirement. The background normalization is set equal to that of the data for events passing the preselection and being in the $m_{\ell\ell j}$ 100-180 GeV region. The signal normalization assumes the SM Higgs boson inclusive production cross-section, $\mathcal{B}(H\to Za)=100\%$, and it is scaled up by a factor of 100. The error bars (hatched regions) represent the data (MC) sample's statistical uncertainty in the histograms and the ratio plots. Vertical arrows indicate data points that fall outside the displayed $y$-axis range.

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Measurement of the $t\bar{t}$ cross section and its ratio to the $Z$ production cross section using $pp$ collisions at $\sqrt{s} = 13.6$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Lett.B 848 (2024) 138376, 2024.
Inspire Record 2689657 DOI 10.17182/hepdata.143515

The inclusive top-quark-pair production cross section $\sigma_{t\bar{t}}$ and its ratio to the $Z$-boson production cross section have been measured in proton--proton collisions at $\sqrt{s} = 13.6$ TeV, using 29 fb${}^{-1}$ of data collected in 2022 with the ATLAS experiment at the Large Hadron Collider. Using events with an opposite-charge electron-muon pair and $b$-tagged jets, and assuming Standard Model decays, the top-quark-pair production cross section is measured to be $\sigma_{t\bar{t}} = 850 \pm 3\mathrm{(stat.)}\pm 18\mathrm{(syst.)}\pm 20\mathrm{(lumi.)}$ pb. The ratio of the $t\bar{t}$ and the $Z$-boson production cross sections is also measured, where the $Z$-boson contribution is determined for inclusive $e^+e^-$ and $\mu^+\mu^-$ events in a fiducial phase space. The relative uncertainty on the ratio is reduced compared to the $t\bar{t}$ cross section, thanks to the cancellation of several systematic uncertainties. The result for the ratio, $R_{t\bar{t}/Z} = 1.145 \pm 0.003\mathrm{(stat.)}\pm 0.021\mathrm{(syst.)}\pm 0.002\mathrm{(lumi.)}$ is consistent with the Standard Model prediction using the PDF4LHC21 PDF set.

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The measured $t\bar{t}$ cross section and the ratio of the cross sections of $t\bar{t}$ and the $Z$-boson. Full phase-space is considered for $t\bar{t}$, while fiducial phase-space is considered for the $Z$-boson.

Table with pre-fit yields in the four regions used in the measurement

Table with post-fit yields in the four regions used in the measurement. The correlations of the nuisance parameters, as obtained by the fit, are considered for the calculation of the uncertainties.


A measurement of the high-mass $\tau\bar{\tau}$ production cross-section at $\sqrt{s}=13$ TeV with the ATLAS detector and constraints on new particles and couplings

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
CERN-EP-2025-063, 2025.
Inspire Record 2905252 DOI 10.17182/hepdata.155470

The production cross-section of high-mass $\tau$-lepton pairs is measured as a function of the dilepton visible invariant mass, using 140 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider. The measurement agrees with the predictions of the Standard Model. A fit to the invariant mass distribution is performed as a function of $b$-jet multiplicity, to constrain the non-resonant production of new particles described by an effective field theory or in models containing leptoquarks or $Z'$ bosons that couple preferentially to third-generation fermions. The constraints on new particles improve on previous results, and the constraints on effective operators include those affecting the anomalous magnetic moment of the $\tau$-lepton.

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The measured unfolded differential cross sections.

The combined covariance matrix for the differential cross-section distribution.

Statistical covariance matrix for the differential cross-section distribution.

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Search for cascade decays of charged sleptons and sneutrinos in final states with three leptons and missing transverse momentum in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
CERN-EP-2025-045, 2025.
Inspire Record 2901728 DOI 10.17182/hepdata.157553

A search for cascade decays of charged sleptons and sneutrinos using final states characterized by three leptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on a dataset with 140 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of $\sqrt{s}$=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. This paper focuses on a supersymmetric scenario that is motivated by the muon anomalous magnetic moment observation, dark mattter relic density abundance, and electroweak naturalness. A mass spectrum involving light higgsinos and heavier sleptons with a bino at intermediate mass is targeted. No significant deviation from the Standard Model expectation is observed. This search enables to place stringent constraints on this model, excluding at the 95% confidence level charged slepton and sneutrino masses up to 450 GeV when assuming a lightest neutralino mass of 100 GeV and mass-degenerate selectrons, smuons and sneutrinos.

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Distribution of $m_{3\ell}$ in SROS-on-$eee$. The SR selections are applied for each distribution, except for the variable shown, for which the selection is indicated by a black arrow. The last bin includes the overflow. The `Others' category contains the production of Higgs boson, 3-top, 4-top, and single-top processes. Distributions for SBH signals are overlaid. The bottom panels show the ratio of the observed data to the predicted total background yields. The hatched band includes all statistical and systematic uncertainties.

Distribution of $m_{3\ell}$ in SROS-on-$e\mu\mu$. The SR selections are applied for each distribution, except for the variable shown, for which the selection is indicated by a black arrow. The last bin includes the overflow. The `Others' category contains the production of Higgs boson, 3-top, 4-top, and single-top processes. Distributions for SBH signals are overlaid. The bottom panels show the ratio of the observed data to the predicted total background yields. The hatched band includes all statistical and systematic uncertainties.

Distribution of $E_{\text{T}}^{\text{miss}}$ in SROS-on-b-$eee$. The SR selections are applied for each distribution, except for the variable shown, for which the selection is indicated by a black arrow. The last bin includes the overflow. The `Others' category contains the production of Higgs boson, 3-top, 4-top, and single-top processes. Distributions for SBH signals are overlaid. The bottom panels show the ratio of the observed data to the predicted total background yields. The hatched band includes all statistical and systematic uncertainties.

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Measurement of the Z boson invisible width at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Lett.B 854 (2024) 138705, 2024.
Inspire Record 2730743 DOI 10.17182/hepdata.151651

A measurement of the invisible width of the $Z$ boson using events with jets and missing transverse momentum is presented using 37 $\mbox{fb\(^{-1}\)}$ of 13 TeV proton-proton data collected by the ATLAS detector in 2015 and 2016. The ratio of $Z\rightarrow \textrm{inv}$ to $Z\rightarrow\ell\ell$ events, where inv refers to non-detected particles and $\ell$ is either an electron or a muon, is measured and corrected for detector effects. Events with at least one energetic central jet with $p_{\textrm{T}} \geq 110$ GeV are selected for both the $Z\rightarrow \textrm{inv}$ and $Z\rightarrow\ell\ell$ final states to obtain a similar phase space in the ratio. The invisible width is measured to be $506\pm2 \textrm{ (stat.)} \pm12 \textrm{ (syst.)}$ MeV and is the single most precise recoil-based measurement. The result is in agreement with the most precise determination from LEP and the Standard Model prediction based on three neutrino generations.

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Measured invisible width of the $Z$ boson, $\Gamma(Z\rightarrow \textrm{inv})$.

Measured $\mathrm{R}^{\mathrm{miss}}_{ee}$.

Measured $\mathrm{R}^{\mathrm{miss}}_{\mu\mu}$.

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Measurement of double-differential charged-current Drell-Yan cross-sections at high transverse masses in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Aakvaag, Erlend ; Abbott, Braden Keim ; et al.
CERN-EP-2025-032, 2025.
Inspire Record 2895869 DOI 10.17182/hepdata.157918

This paper presents a first measurement of the cross-section for the charged-current Drell-Yan process $pp\rightarrow W^{\pm} \rightarrow \ell^{\pm} \nu$ above the resonance region, where $\ell$ is an electron or muon. The measurement is performed for transverse masses, $m_{\text{T}}^{\text{W}}$, between 200 GeV and 5000 GeV, using a sample of 140~fb$^{-1}$ of $pp$ collision data at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV collected by the ATLAS detector at the LHC during 2015-2018. The data are presented single differentially in transverse mass and double differentially in transverse mass and absolute lepton pseudorapidity. A test of lepton flavour universality shows no significant deviations from the Standard Model. The electron and muon channel measurements are combined to achieve a total experimental precision of 3% at low $m_{\text{T}}^{\text{W}}$. The single- and double differential $W$-boson charge asymmetries are evaluated from the measurements. A comparison to next-to-next-to-leading-order perturbative QCD predictions using several recent parton distribution functions and including next-to-leading-order electroweak effects indicates the potential of the data to constrain parton distribution functions. The data are also used to constrain four fermion operators in the Standard Model Effective Field Theory formalism, in particular the lepton-quark operator Wilson coefficient $c_{\ell q}^{(3)}.$

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Born-level single-differential cross section $\frac{d\sigma (W^+\to e^+\nu) }{d m_{\text{T}}^{W} } $ including the absolute statistical and systematic uncertainties. Symmetric uncertainties are denoted by $\pm$ or $\mp$, where the upper sign corresponds to the one standard deviation upward shift of the uncertainty source. The systematic uncertainties are related to the unfolding procedure (``unf.''), the jet energy scale/resolution (``JER/JES''), the \met scale and resolution, the electron and muon scale, resolution and efficiency (``Eff.''), the multijet and $t\bar{t}$ (where RW refers to a reweighting to NNLO) background estimates and normalization of small background processes (``Norm.''). The luminosity uncertainty of $0.83\%$ is not included.

Born-level single-differential cross section $\frac{d\sigma (W^-\to e^-\bar{\nu}) }{d m_{\text{T}}^{W} } $ including the absolute statistical and systematic uncertainties. Symmetric uncertainties are denoted by $\pm$ or $\mp$, where the upper sign corresponds to the one standard deviation upward shift of the uncertainty source. The systematic uncertainties are related to the unfolding procedure (``unf.''), the jet energy scale/resolution (``JER/JES''), the \met scale and resolution, the electron and muon scale, resolution and efficiency (``Eff.''), the multijet and $t\bar{t}$ (where RW refers to a reweighting to NNLO) background estimates and normalization of small background processes (``Norm.''). The luminosity uncertainty of $0.83\%$ is not included.

Born-level single-differential cross section $\frac{d\sigma (W\to e\nu) }{d m_{\text{T}}^{W} } $ including the absolute statistical and systematic uncertainties. Symmetric uncertainties are denoted by $\pm$ or $\mp$, where the upper sign corresponds to the one standard deviation upward shift of the uncertainty source. The systematic uncertainties are related to the unfolding procedure (``unf.''), the jet energy scale/resolution (``JER/JES''), the \met scale and resolution, the electron and muon scale, resolution and efficiency (``Eff.''), the multijet and $t\bar{t}$ (where RW refers to a reweighting to NNLO) background estimates and normalization of small background processes (``Norm.''). The luminosity uncertainty of $0.83\%$ is not included.

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