Version 2
A measurement of soft-drop jet observables in $pp$ collisions with the ATLAS detector at $\sqrt{s} = 13$ TeV

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Phys.Rev.D 101 (2020) 052007, 2020.
Inspire Record 1772062 DOI 10.17182/hepdata.92073

Jet substructure quantities are measured using jets groomed with the soft-drop grooming procedure in dijet events from 32.9 fb$^{-1}$ of $pp$ collisions collected with the ATLAS detector at $\sqrt{s} = 13$ TeV. These observables are sensitive to a wide range of QCD phenomena. Some observables, such as the jet mass and opening angle between the two subjets which pass the soft-drop condition, can be described by a high-order (resummed) series in the strong coupling constant $\alpha_S$. Other observables, such as the momentum sharing between the two subjets, are nearly independent of $\alpha_S$. These observables can be constructed using all interacting particles or using only charged particles reconstructed in the inner tracking detectors. Track-based versions of these observables are not collinear safe, but are measured more precisely, and universal non-perturbative functions can absorb the collinear singularities. The unfolded data are directly compared with QCD calculations and hadron-level Monte Carlo simulations. The measurements are performed in different pseudorapidity regions, which are then used to extract quark and gluon jet shapes using the predicted quark and gluon fractions in each region. All of the parton shower and analytical calculations provide an excellent description of the data in most regions of phase space.

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Data from Fig 6a. The unfolded all-particle $log_{10}(\rho^2)$ distribution for anti-kt R=0.8 jets with $p_T$ > 300 GeV, after the soft drop algorithm is applied for $\beta$ = 0, in data. All uncertainties described in the text are shown on the data. The distributions are normalized to the integrated cross section, $\sigma$(resum), measured in the resummation region, $-3.7 < log_{10}(\rho^2) < -1.7$.

Data from Fig 6a. The unfolded all-particle $log_{10}(\rho^2)$ distribution for anti-kt R=0.8 jets with $p_T$ > 300 GeV, after the soft drop algorithm is applied for $\beta$ = 0, in data. All uncertainties described in the text are shown on the data. The distributions are normalized to the integrated cross section, $\sigma$(resum), measured in the resummation region, $-3.7 < log_{10}(\rho^2) < -1.7$.

Data from Fig 6b. The unfolded charged-particle $log_{10}(\rho^2)$ distribution for anti-kt R=0.8 jets with $p_T$ > 300 GeV, after the soft drop algorithm is applied for $\beta$ = 0, in data. All uncertainties described in the text are shown on the data. The distributions are normalized to the integrated cross section, $\sigma$(resum), measured in the resummation region, $-3.7 < log_{10}(\rho^2) < -1.7$.

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Searches for scalar leptoquarks and differential cross-section measurements in dilepton-dijet events in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV with the ATLAS experiment

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 79 (2019) 733, 2019.
Inspire Record 1718132 DOI 10.17182/hepdata.83968

Searches for scalar leptoquarks pair-produced in proton-proton collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider are performed by the ATLAS experiment. A data set corresponding to an integrated luminosity of 36.1 fb$^{-1}$ is used. Final states containing two electrons or two muons and two or more jets are studied, as are states with one electron or muon, missing transverse momentum and two or more jets. No statistically significant excess above the Standard Model expectation is observed. The observed and expected lower limits on the leptoquark mass at 95% confidence level extend up to 1.29 TeV and 1.23 TeV for first- and second-generation leptoquarks, respectively, as postulated in the minimal Buchm\"uller-R\"uckl-Wyler model, assuming a branching ratio into a charged lepton and a quark of 50%. In addition, measurements of particle-level fiducial and differential cross sections are presented for the $Z\rightarrow ee$, $Z\rightarrow\mu\mu$ and $t\bar{t}$ processes in several regions related to the search control regions. Predictions from a range of generators are compared with the measurements, and good agreement is seen for many of the observables. However, the predictions for the $Z\rightarrow\ell\ell$ measurements in observables sensitive to jet energies disagree with the data.

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Inclusive cross-section and uncertainty from each source, for the dominant process in the each measurement region.

Differential cross-section and uncertainty from each source, as a function of leading $p_{T}^j$ for the dominant process in the $eejj$ measurement region.

Differential cross-section and uncertainty from each source, as a function of leading $p_{T}^j$ for the dominant process in the $\mu\mu jj$ measurement region.

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Properties of $g\rightarrow b\bar{b}$ at small opening angles in $pp$ collisions with the ATLAS detector at $\sqrt{s}=13$ TeV

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 99 (2019) 052004, 2019.
Inspire Record 1711114 DOI 10.17182/hepdata.85697

The fragmentation of high-energy gluons at small opening angles is largely unconstrained by present measurements. Gluon splitting to $b$-quark pairs is a unique probe into the properties of gluon fragmentation because identified $b$-tagged jets provide a proxy for the quark daughters of the initial gluon. In this study, key differential distributions related to the $g\rightarrow b\bar{b}$ process are measured using 33 fb$^{-1}$ of $\sqrt{s}=13$ TeV $pp$ collision data recorded by the ATLAS experiment at the LHC in 2016. Jets constructed from charged-particle tracks, clustered with the anti-$k_t$ jet algorithm with radius parameter $R = 0.2$, are used to probe angular scales below the $R=0.4$ jet radius. The observables are unfolded to particle level in order to facilitate direct comparisons with predictions from present and future simulations. Multiple significant differences are observed between the data and parton shower Monte Carlo predictions, providing input to improve these predictions of the main source of background events in analyses involving boosted Higgs bosons decaying into $b$-quarks.

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Normalisaed differential cross section, $(1/\sigma_\text{fid})d\sigma_\text{fid}/d\Delta R(b,b)$, as a function of $\Delta R(b,b)$ - the angle in $\eta$ and $\phi$ between the two b-tagged jets.

Normalisaed differential cross section, $(1/\sigma_\text{fid})d\sigma_\text{fid}/d\Delta\theta_\text{gpp,gbb}/\pi$, the angle between production (gpp) and decay (gbb) planes ($\Delta\theta_\text{gpp,gbb}$).

Normalisaed differential cross section, $(1/\sigma_\text{fid})d\sigma_\text{fid}/dz(p_\text{T})$, as a function of $z(p_\text{T})=p_\text{T,2}/(p_\text{T,1}+p_\text{T,2})$.

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Underlying-event studies with strange hadrons 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-2024-105, 2024.
Inspire Record 2784422 DOI 10.17182/hepdata.146740

Properties of the underlying-event in $pp$ interactions are investigated primarily via the strange hadrons $K_{S}^{0}$, $\Lambda$ and $\bar\Lambda$, as reconstructed using the ATLAS detector at the LHC in minimum-bias $pp$ collision data at $\sqrt{s} = 13$ TeV. The hadrons are reconstructed via the identification of the displaced two-particle vertices corresponding to the decay modes $K_{S}^{0}\rightarrow\pi^+\pi^-$, $\Lambda\rightarrow\pi^-p$ and $\bar\Lambda\rightarrow\pi^+\bar{p}$. These are used in the construction of underlying-event observables in azimuthal regions computed relative to the leading charged-particle jet in the event. None of the hadronisation and underlying-event physics models considered can describe the data over the full kinematic range considered. Events with a leading charged-particle jet in the range of $10 < p_T \leq 40$ GeV are studied using the number of prompt charged particles in the transverse region. The ratio $N(\Lambda\rightarrow\pi^\mp p^\pm)/N(K_{S}^{0}\rightarrow\pi^+\pi^-)$ as a function of the number of such charged particles varies only slightly over this range. This disagrees with the expectations of some of the considered Monte Carlo models.

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Mean multiplicity of $K^{0}_{S}$ per unit $(\eta, \phi)$ in the away region vs. leading-jet $p_{T}$

Mean multiplicity of $K^{0}_{S}$ per unit $(\eta, \phi)$ in the towards region vs. leading-jet $p_{T}$

Mean multiplicity of $K^{0}_{S}$ per unit $(\eta, \phi)$ in the transverse region vs. leading-jet $p_{T}$

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Measurement of charged-particle event shape variables in sqrt(s) = 7 TeV proton-proton interactions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abajyan, Tatevik ; Abbott, Brad ; et al.
Phys.Rev.D 88 (2013) 032004, 2013.
Inspire Record 1124167 DOI 10.17182/hepdata.58968

The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged particle transverse momentum, charged particle multiplicity and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data.

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Normalized distributions of Tranverse Thrust for 4 ranges of leading particle PT.

Normalized distributions of Tranverse Thrust for 5 lower limit values of leading particle PT.

Normalized distributions of Tranverse Thrust Minor for 4 ranges of leading particle PT.

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Version 2
Measurements of the W production cross sections in association with jets with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 75 (2015) 82, 2015.
Inspire Record 1319490 DOI 10.17182/hepdata.66683

This paper presents cross sections for the production of a W boson in association with jets, measured in proton--proton collisions at $\sqrt{s}=7$ TeV with the ATLAS experiment at the Large Hadron Collider. With an integrated luminosity of $4.6 fb^{-1}$, this data set allows for an exploration of a large kinematic range, including jet production up to a transverse momentum of 1 TeV and multiplicities up to seven associated jets. The production cross sections for W bosons are measured in both the electron and muon decay channels. Differential cross sections for many observables are also presented including measurements of the jet observables such as the rapidities and the transverse momenta as well as measurements of event observables such as the scalar sums of the transverse momenta of the jets. The measurements are compared to numerous QCD predictions including next-to-leading-order perturbative calculations, resummation calculations and Monte Carlo generators.

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Distribution of inclusive jet multiplicity.

Breakdown of systematic uncertainties in percent in inclusive jet multiplicity in the electron channel.Uncertainties have been symmetrised and the sign denotes the sign of the original up-variation.

Breakdown of systematic uncertainties in percent in inclusive jet multiplicity in the muon channel.Uncertainties have been symmetrised and the sign denotes the sign of the original up-variation.

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Differential cross-section measurements for the electroweak production of dijets in association with a $Z$ boson in proton-proton collisions at ATLAS

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 81 (2021) 163, 2021.
Inspire Record 1803608 DOI 10.17182/hepdata.94218

Differential cross-section measurements are presented for the electroweak production of two jets in association with a $Z$ boson. These measurements are sensitive to the vector-boson fusion production mechanism and provide a fundamental test of the gauge structure of the Standard Model. The analysis is performed using proton-proton collision data collected by ATLAS at $\sqrt{s}$=13 TeV and with an integrated luminosity of 139 fb$^{-1}$. The differential cross-sections are measured in the $Z\rightarrow \ell^+\ell^-$ decay channel ($\ell=e,\mu$) as a function of four observables: the dijet invariant mass, the rapidity interval spanned by the two jets, the signed azimuthal angle between the two jets, and the transverse momentum of the dilepton pair. The data are corrected for the effects of detector inefficiency and resolution and are sufficiently precise to distinguish between different state-of-the-art theoretical predictions calculated using Powheg+Pythia8, Herwig7+Vbfnlo and Sherpa 2.2. The differential cross-sections are used to search for anomalous weak-boson self-interactions using a dimension-six effective field theory. The differential cross-section as a function of the signed azimuthal angle between the two jets is found to be particularly sensitive to the interference between the Standard Model and dimension-six scattering amplitudes and provides a direct test of charge-conjugation and parity invariance in the weak-boson self-interactions.

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Differential cross-sections for EW $Zjj$ production as a function of $m_{jj}$ with breakdown of associated uncertainties. The statistical uncertainty is correlated across bins according to the statistical cross correlation matrix presented in Table 21.

Differential cross-sections for EW $Zjj$ production as a function of $|\Delta y_{jj}|$ with breakdown of associated uncertainties. The statistical uncertainty is correlated across bins according to the statistical cross correlation matrix presented in Table 21.

Differential cross-sections for EW $Zjj$ production as a function of $p_{\mathrm{T},\ell\ell}$ with breakdown of associated uncertainties. The statistical uncertainty is correlated across bins according to the statistical cross correlation matrix presented in Table 21.

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Measurements of multijet event isotropies using optimal transport with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
JHEP 10 (2023) 060, 2023.
Inspire Record 2663035 DOI 10.17182/hepdata.110164

A measurement of novel event shapes quantifying the isotropy of collider events is performed in 140 fb$^{-1}$ of proton-proton collisions with $\sqrt s=13$ TeV centre-of-mass energy recorded with the ATLAS detector at CERN's Large Hadron Collider. These event shapes are defined as the Wasserstein distance between collider events and isotropic reference geometries. This distance is evaluated by solving optimal transport problems, using the 'Energy-Mover's Distance'. Isotropic references with cylindrical and circular symmetries are studied, to probe the symmetries of interest at hadron colliders. The novel event-shape observables defined in this way are infrared- and collinear-safe, have improved dynamic range and have greater sensitivity to isotropic radiation patterns than other event shapes. The measured event-shape variables are corrected for detector effects, and presented in inclusive bins of jet multiplicity and the scalar sum of the two leading jets' transverse momenta. The measured distributions are provided as inputs to future Monte Carlo tuning campaigns and other studies probing fundamental properties of QCD and the production of hadronic final states up to the TeV-scale.

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IRing2 for HT2>=500 GeV, NJets>=2

IRing2 for HT2>=500 GeV, NJets>=3

IRing2 for HT2>=500 GeV, NJets>=4

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Measurements of $W^+W^-+\ge 1~$jet production cross-sections in $pp$ collisions at $\sqrt{s}=13~$TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale Charles ; et al.
JHEP 06 (2021) 003, 2021.
Inspire Record 1852328 DOI 10.17182/hepdata.100511

Fiducial and differential measurements of $W^+W^-$ production in events with at least one hadronic jet are presented. These cross-section measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton$-$proton collision data collected at $\sqrt{s}=13~$TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139$~$fb$^{-1}$. Events are selected with exactly one oppositely charged electron$-$muon pair and at least one hadronic jet with a transverse momentum of $p_{\mathrm{T}}>30~$GeV and a pseudorapidity of $|\eta|<4.5$. After subtracting the background contributions and correcting for detector effects, the jet-inclusive $W^+W^-+\ge 1~$jet fiducial cross-section and $W^+W^-+$ jets differential cross-sections with respect to several kinematic variables are measured, thus probing a previously unexplored event topology at the LHC. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the $W^+W^-$ system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced.

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Measured fiducial cross section for $pp\rightarrow W^+W^-$+jets production. The second column contains the results obtained with a fiducial particle phase space that includes a veto on $b$-jets. This alternative result is obtained from the nominal result by the application of bin-wise correction that is calculated as the ratio of the predicted differential cross-section in the nominal analysis phase space and the predicted cross-section for a phase space that includes a veto on events with $b$-jets with $p_{\mathrm{T}} > 20$ GeV. Also shown are the Standard Model predictions for $q\bar{q} \rightarrow WW$, obtained from Sherpa 2.2.2, MadGraph 2.3.3 + Pythia 8.212 using FxFx merging, and Powheg MiNLO + Pythia 8.244. These predictions are supplemented by the Sherpa 2.2.2 + OpenLoops simulation of $gg\rightarrow WW$. Finally, the prediction from MATRIX is given, which includes nNLO QCD and NLO EW corrections to $WW$+jet production.

Measured fiducial cross section for $pp\rightarrow W^+W^-$+jets production for the observable $p_{\mathrm{T}}^{\mathrm{lead.~lep.}}$. The second column contains the results obtained with a fiducial particle phase space that includes a veto on $b$-jets. This alternative result is obtained from the nominal result by the application of bin-wise correction that is calculated as the ratio of the predicted differential cross-section in the nominal analysis phase space and the predicted cross-section for a phase space that includes a veto on events with $b$-jets with $p_{\mathrm{T}} > 20$ GeV. Also shown are the Standard Model predictions for $q\bar{q} \rightarrow WW$, obtained from Sherpa 2.2.2, MadGraph 2.3.3 + Pythia 8.212 using FxFx merging, and Powheg MiNLO + Pythia 8.244. These predictions are supplemented by the Sherpa 2.2.2 + OpenLoops simulation of $gg\rightarrow WW$. Finally, the prediction from MATRIX is given, which includes nNLO QCD and NLO EW corrections to $WW$+jet production. Overflow events are included in the last bin. The largest observed value is 1168 GeV.

Correlation matrix of the statistical uncertainties in the measured fiducial cross section for the observable $p_{\mathrm{T}}^{\mathrm{lead.~lep.}}$

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Measurement of $W^{\pm}$-boson and $Z$-boson production cross-sections in $pp$ collisions at $\sqrt{s}=2.76$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Eur.Phys.J.C 79 (2019) 901, 2019.
Inspire Record 1742785 DOI 10.17182/hepdata.91267

The production cross-sections for $W^{\pm}$ and $Z$ bosons are measured using ATLAS data corresponding to an integrated luminosity of 4.0 pb$^{-1}$ collected at a centre-of-mass energy $\sqrt{s}=2.76$ TeV. The decay channels $W \rightarrow \ell \nu$ and $Z \rightarrow \ell \ell $ are used, where $\ell$ can be an electron or a muon. The cross-sections are presented for a fiducial region defined by the detector acceptance and are also extrapolated to the full phase space for the total inclusive production cross-section. The combined (average) total inclusive cross-sections for the electron and muon channels are: \begin{eqnarray} \sigma^{\text{tot}}_{W^{+}\rightarrow \ell \nu}& = & 2312 \pm 26\ (\text{stat.})\ \pm 27\ (\text{syst.}) \pm 72\ (\text{lumi.}) \pm 30\ (\text{extr.})\text{pb} \nonumber, \\ \sigma^{\text{tot}}_{W^{-}\rightarrow \ell \nu}& = & 1399 \pm 21\ (\text{stat.})\ \pm 17\ (\text{syst.}) \pm 43\ (\text{lumi.}) \pm 21\ (\text{extr.})\text{pb} \nonumber, \\ \sigma^{\text{tot}}_{Z \rightarrow \ell \ell}& = & 323.4 \pm 9.8\ (\text{stat.}) \pm 5.0\ (\text{syst.}) \pm 10.0\ (\text{lumi.}) \pm 5.5 (\text{extr.}) \text{pb} \nonumber. \end{eqnarray} Measured ratios and asymmetries constructed using these cross-sections are also presented. These observables benefit from full or partial cancellation of many systematic uncertainties that are correlated between the different measurements.

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Measured fiducial cross section times leptonic branching ratio for W+ production in the W+ -> e+ nu final state.

Measured fiducial cross section times leptonic branching ratio for W+ production in the W+ -> mu+ nu final state.

Measured fiducial cross section times leptonic branching ratio for W- production in the W- -> e- nu final state.

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