Combination of inclusive top-quark pair production cross-section measurements using ATLAS and CMS data at $\sqrt{s}= 7$ and 8 TeV

The ATLAS & CMS collaborations Aad, G. ; Abbott, B. ; Abbott, D.C. ; et al.
JHEP 07 (2023) 213, 2023.
Inspire Record 2088291 DOI 10.17182/hepdata.110250

A combination of measurements of the inclusive top-quark pair production cross-section performed by ATLAS and CMS in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV at the LHC is presented. The cross-sections are obtained using top-quark pair decays with an opposite-charge electron-muon pair in the final state and with data corresponding to an integrated luminosity of about 5 fb$^{-1}$ at $\sqrt{s}=7$ TeV and about 20 fb$^{-1}$ at $\sqrt{s}=8$ TeV for each experiment. The combined cross-sections are determined to be $178.5 \pm 4.7$ pb at $\sqrt{s}=7$ TeV and $243.3^{+6.0}_{-5.9}$ pb at $\sqrt{s}=8$ TeV with a correlation of 0.41, using a reference top-quark mass value of 172.5 GeV. The ratio of the combined cross-sections is determined to be $R_{8/7}= 1.363\pm 0.032$. The combined measured cross-sections and their ratio agree well with theory calculations using several parton distribution function (PDF) sets. The values of the top-quark pole mass (with the strong coupling fixed at 0.118) and the strong coupling (with the top-quark pole mass fixed at 172.5 GeV) are extracted from the combined results by fitting a next-to-next-to-leading-order plus next-to-next-to-leading-log QCD prediction to the measurements. Using a version of the NNPDF3.1 PDF set containing no top-quark measurements, the results obtained are $m_t^\text{pole} = 173.4^{+1.8}_{-2.0}$ GeV and $\alpha_\text{s}(m_Z)= 0.1170^{+ 0.0021}_{-0.0018}$.

2 data tables

Full covariance matrix including all systematic uncertainties expressed as nuisance parameters. With the exception of the cross section parameters, all parameters were normalised to 1 before the fit. Therefore, the diagonal elements represent the constraint in quadrature.

Full covariance matrix including all systematic uncertainties expressed as nuisance parameters. With the exception of the cross section parameters, all parameters were normalised to 1 before the fit. Therefore, the diagonal elements represent the constraint in quadrature.


Evidence for the Higgs boson decay to a $Z$ boson and a photon at the LHC

The ATLAS & CMS collaborations Aad, Georges ; Abbott, Braden Keim ; Abeling, Kira ; et al.
Phys.Rev.Lett. 132 (2024) 021803, 2024.
Inspire Record 2666787 DOI 10.17182/hepdata.142406

The first evidence for the Higgs boson decay to a $Z$ boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision data sets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140 fb$^{-1}$ for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is $2.2\pm0.7$ times the Standard Model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.

1 data table

The negative profile log-likelihood test statistic, where $\Lambda$ represents the likelihood ratio, as a function of the signal strength $\mu$ derived from the ATLAS data, the CMS data, and the combined result.


Version 2
Charged-particle distributions at low transverse momentum in $\sqrt{s}$=13 TeV pp interactions measured with the ATLAS detector at the LHC

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 76 (2016) 502, 2016.
Inspire Record 1467230 DOI 10.17182/hepdata.73907

Measurements of distributions of charged particles produced in proton-proton collisions with a centre-of-mass energy of 13 TeV are presented. The data were recorded by the ATLAS detector at the LHC and correspond to an integrated luminosity of 151 $\mu$b$^{-1}$. The particles are required to have a transverse momentum greater than 100 MeV and an absolute pseudorapidity less than 2.5. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on multiplicity are measured in events containing at least two charged particles satisfying the above kinematic criteria. The results are corrected for detector effects and compared to the predictions from several Monte Carlo event generators.

20 data tables

The average charged-particle muliplicity per unit of rapidity for ETARAP=0 as a function of the centre-of-mass energy.

The average charged-particle muliplicity per unit of rapidity for ETARAP=0 as a function of the centre-of-mass energy.

The extrapolated ($\tau > 30$ ps) average charged-particle muliplicity per unit of rapidity for ETARAP=0 as a function of the centre-of-mass energy.

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Version 2
Search for resonant $WZ$ production in the fully leptonic final state in proton-proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, M. ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Lett.B 787 (2018) 68-88, 2018.
Inspire Record 1676472 DOI 10.17182/hepdata.82546

A search for a heavy resonance decaying into $WZ$ in the fully leptonic channel (electrons and muons) is performed. It is based on proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. No significant excess is observed over the Standard Model predictions and limits are set on the production cross section times branching ratio of a heavy vector particle produced either in quark-antiquark fusion or through vector-boson fusion. Constraints are also obtained on the mass and couplings of a singly charged Higgs boson, in the Georgi-Machacek model, produced through vector-boson fusion.

18 data tables

The signal selection acceptance times efficiency (A$\times\epsilon$), defined as the ratio of the number of MC signal events in the category to the number of generated signal events, is presented as a function of the Georgi-Machacek Model $H_5^\pm$ resonance mass in the VBF category. The A$\times\epsilon$ is shown for the combination of all decay channels. For the Georgi-Machacek Model $H_5^\pm$ samples, generator cuts are: $p_{\mathrm T}$ (jets) $>$ 15 GeV, $p_{\mathrm T}$ (leptons) $>$ 10 GeV, $|\eta|$(jets) $<$ 5 and $|\eta|$(leptons) $<$ 2.7. The decay of $W$ is to all flavors of leptons and of $Z$ to $e^+e^−$ and $\mu^+\mu^-$. The $Z$ to $\tau^+\tau-$ decays give a negligible contribution and were not included in the simulation, however the acceptancs shown here was scaled to include all decays. A systematic uncertainty was applied to cover the scaling uncertainty. The uncertainty shown represents the total statistical and systematic uncertainties.

The signal selection acceptance times efficiency (A$\times\epsilon$), defined as the ratio of the number of MC signal events in the category to the number of generated signal events, is presented as a function of the Georgi-Machacek Model $H_5^\pm$ resonance mass in the VBF category. The A$\times\epsilon$ is shown for the combination of all decay channels. For the Georgi-Machacek Model $H_5^\pm$ samples, generator cuts are: $p_{\mathrm T}$ (jets) $>$ 15 GeV, $p_{\mathrm T}$ (leptons) $>$ 10 GeV, $|\eta|$(jets) $<$ 5 and $|\eta|$(leptons) $<$ 2.7. The decay of $W$ is to all flavors of leptons and of $Z$ to $e^+e^−$ and $\mu^+\mu^-$. The $Z$ to $\tau^+\tau-$ decays give a negligible contribution and were not included in the simulation, however the acceptancs shown here was scaled to include all decays. A systematic uncertainty was applied to cover the scaling uncertainty. The uncertainty shown represents the total statistical and systematic uncertainties.

The signal selection acceptance times efficiency (A$\times \epsilon$), defined as the ratio of the number of MC signal events in the category to the number of generated signal events, is presented as a function of the HVT resonance mass in the VBF category. The A$\times \epsilon$ is shown for the combination of all decay channels. For the HVT VBF samples, generator cuts are: m$_{jj} >$ 150 GeV. The decay of $W$ and $Z$ are to all flavors of leptons. The uncertainty shown represents the total statistical and systematic uncertainties.

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Version 2
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

The ATLAS collaboration Aad, Georges ; Abajyan, Tatevik ; Abbott, Brad ; et al.
Phys.Lett.B 726 (2013) 88-119, 2013.
Inspire Record 1241574 DOI 10.17182/hepdata.61748

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, $H\rightarrow\gamma\gamma$, $H\rightarrow ZZ^{*}\rightarrow 4 \ell$ and $H\rightarrow W W \rightarrow \ell\nu\ell\nu$. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of about 25 fb$^{-1}$. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson.

3 data tables

-2 log Likelihood in the $(\mu^f_{{\mathrm{{ggF}}+ttH}}, \mu^f_{{\mathrm{{VBF}}+VH}})$ plane for the $f=H\to \gamma\gamma$ channel and a Higgs boson mass $m_H = 125.5$ GeV. The original plain-text and ROOT files from <a href="https://doi.org/10.7484/inspirehep.data.a78c.hk44">10.7484/inspirehep.data.a78c.hk44</a> are accessible by clicking "Resources".

-2 log Likelihood in the $(\mu^f_{{\mathrm{{ggF}}+ttH}}, \mu^f_{{\mathrm{{VBF}}+VH}})$ plane for the $f=H\to ZZ^*\to 4\ell$ channel and a Higgs boson mass $m_H = 125.5$ GeV. The sharp lower edge is due to the small number of events in this channel and the requirement of a positive pdf. The original plain-text and ROOT files from <a href="https://doi.org/10.7484/inspirehep.data.rf5p.6m3k">10.7484/inspirehep.data.rf5p.6m3k</a> are accessible by clicking "Resources".

-2 log Likelihood in the $(\mu^f_{{\mathrm{{ggF}}+ttH}}, \mu^f_{{\mathrm{{VBF}}+VH}})$ plane for the $f=H\to WW^*\to\ell\nu\ell\nu$ channel and a Higgs boson mass $m_H = 125.5$ GeV. The original plain-text and ROOT files from <a href="https://doi.org/10.7484/inspirehep.data.26b4.ty5f">10.7484/inspirehep.data.26b4.ty5f</a> are accessible by clicking "Resources".


Prompt and non-prompt $J/\psi$ and $\psi(2\mathrm{S})$ suppression at high transverse momentum in 5.02 TeV Pb+Pb collisions with the ATLAS experiment

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Eur.Phys.J.C 78 (2018) 762, 2018.
Inspire Record 1672469 DOI 10.17182/hepdata.103082

A measurement of $J/\psi$ and $\psi(2\mathrm{S})$ production is presented. It is based on a data sample from Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV and $pp$ collisions at $\sqrt{s}$ = 5.02 TeV recorded by the ATLAS detector at the LHC in 2015, corresponding to an integrated luminosity of $0.42\mathrm{nb}^{-1}$ and $25\mathrm{pb}^{-1}$ in Pb+Pb and $pp$, respectively. The measurements of per-event yields, nuclear modification factors, and non-prompt fractions are performed in the dimuon decay channel for $9 < p_{T}^{\mu\mu} < 40$ GeV in dimuon transverse momentum, and $-2.0 < y_{\mu\mu} < 2.0$ in rapidity. Strong suppression is found in Pb+Pb collisions for both prompt and non-prompt $J/\psi$, as well as for prompt and non-prompt $\psi(2\mathrm{S})$, increasing with event centrality. The suppression of prompt $\psi(2\mathrm{S})$ is observed to be stronger than that of $J/\psi$, while the suppression of non-prompt $\psi(2\mathrm{S})$ is equal to that of the non-prompt $J/\psi$ within uncertainties, consistent with the expectation that both arise from \textit{b}-quarks propagating through the medium. Despite prompt and non-prompt $J/\psi$ arising from different mechanisms, the dependence of their nuclear modification factors on centrality is found to be quite similar.

17 data tables

Per-event-yield of prompt jpsi production in 5.02 TeV PbPb collision data as a function of pT for three different centrality slices in the rapidity range |y| < 2.

Per-event-yield of non-prompt jpsi production in 5.02 TeV PbPb collision data as a function of pT for three different centrality slices in the rapidity range |y| < 2.

Non-prompt fraction of jpsi production in 5.02 TeV PbPb collision data as a function of pT for three different centrality slices in the rapidity range |y| < 2.

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Version 2
Comprehensive measurements of $t$-channel single top-quark production cross sections at $\sqrt{s} = 7$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.D 90 (2014) 112006, 2014.
Inspire Record 1303905 DOI 10.17182/hepdata.64385

This article presents measurements of the $t$-channel single top-quark ($t$) and top-antiquark ($\bar{t}$) total production cross sections $\sigma(tq)$ and $\sigma(\bar{t}q)$, their ratio $R_{t}=\sigma(tq)/\sigma(\bar{t}q)$, and a measurement of the inclusive production cross section $\sigma(tq + \bar{t}q)$ in proton--proton collisions at $\sqrt{s} = 7$ TeV at the LHC. Differential cross sections for the $tq$ and $\bar{t}q$ processes are measured as a function of the transverse momentum and the absolute value of the rapidity of $t$ and $\bar{t}$, respectively. The analyzed data set was recorded with the ATLAS detector and corresponds to an integrated luminosity of 4.59 fb$^{-1}$. Selected events contain one charged lepton, large missing transverse momentum, and two or three jets. The cross sections are measured by performing a binned maximum-likelihood fit to the output distributions of neural networks. The resulting measurements are $\sigma(tq)= 46\pm 6\; \mathrm{pb}$, $\sigma(\bar{t}q)= 23 \pm 4\; \mathrm{pb}$, $R_{t}=2.04\pm 0.18$, and $\sigma(tq + \bar{t}q)= 68 \pm 8\; \mathrm{pb}$, consistent with the Standard Model expectation. The uncertainty on the measured cross sections is dominated by systematic uncertainties, while the uncertainty on $R_{t}$ is mainly statistical. Using the ratio of $\sigma(tq + \bar{t}q)$ to its theoretical prediction, and assuming that the top-quark-related CKM matrix elements obey the relation $|V_{tb}|\gg |V_{ts}|, |V_{td}|$, we determine $|V_{tb}|=1.02 \pm 0.07$.

40 data tables

Differential t-channel top-quark production cross sections and normalized differential t-channel top-quark production cross sections as functions of PT(TOP).

Predicted and observed events yields for the 2-jet and 3-jet channels considered in this measurement. The multijet background is estimated using data-driven techniques (see Sec. VB); an uncertainty of $50\%$ is applied. All the other expectations are derived using theoretical cross sections and their uncertainties (see Secs. VA and VC in the paper).

Differential t-channel top-quark production cross sections and normalized differential t-channel top-quark production cross sections as functions of PT(TOPBAR).

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Version 6
Search for squarks and gluinos in final states with jets and missing transverse momentum using 36 fb$^{-1}$ of $\sqrt{s}$=13 TeV $pp$ collision data with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 97 (2018) 112001, 2018.
Inspire Record 1641270 DOI 10.17182/hepdata.77891

A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded in 2015 and 2016 by the ATLAS experiment in $\sqrt{s}$=13 TeV proton--proton collisions at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. The results are interpreted in the context of various models where squarks and gluinos are pair-produced and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95\% confidence level on the mass of the gluino is set at 2.03 TeV for a simplified model incorporating only a gluino and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.55 TeV are excluded if the lightest neutralino is massless. These limits substantially extend the region of supersymmetric parameter space previously excluded by searches with the ATLAS detector.

426 data tables

Observed and expected background and signal effective mass distributions for SR2j-2100. For signal, a squark direct decay model where squarks have mass of 600 GeV and the neutralino1 has mass of 595 GeV is shown.

Observed and expected background and signal effective mass distributions for SR2j-2800. For signal, a squark direct decay model where squarks have mass of 1500 GeV and the neutralino1 has mass of 0 GeV is shown.

Observed and expected background and signal effective mass distributions for SR4j-1000. For signal, a gluino direct decay model where gluinos have mass of 1300 GeV and the neutralino1 has mass of 900 GeV is shown.

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Version 2
Search for electroweak production of supersymmetric states in scenarios with compressed mass spectra at $\sqrt{s}=13$ TeV with the ATLAS detector

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
Phys.Rev.D 97 (2018) 052010, 2018.
Inspire Record 1644618 DOI 10.17182/hepdata.80609

A search for electroweak production of supersymmetric particles in scenarios with compressed mass spectra in final states with two low-momentum leptons and missing transverse momentum is presented. This search uses proton-proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015-2016, corresponding to 36.1 fb$^{-1}$ of integrated luminosity at $\sqrt{s}=13$ TeV. Events with same-flavor pairs of electrons or muons with opposite electric charge are selected. The data are found to be consistent with the Standard Model prediction. Results are interpreted using simplified models of R-parity-conserving supersymmetry in which there is a small mass difference between the masses of the produced supersymmetric particles and the lightest neutralino. Exclusion limits at 95% confidence level are set on next-to-lightest neutralino masses of up to 145 GeV for Higgsino production and 175 GeV for wino production, and slepton masses of up to 190 GeV for pair production of sleptons. In the compressed mass regime, the exclusion limits extend down to mass splittings of 2.5 GeV for Higgsino production, 2 GeV for wino production, and 1 GeV for slepton production. The results are also interpreted in the context of a radiatively-driven natural supersymmetry model with non-universal Higgs boson masses.

240 data tables

<b>Kinematics 1</b> Kinematic distributions after the background-only fit showing the data as well as the expected background in the inclusive electroweakino SR&#8467;&#8467;-m<sub>&#8467;&#8467;</sub> [1, 60] (top) and slepton SR&#8467;&#8467;-m<sub>T2</sub><sup>100</sup> [100, &infin;] (bottom) signal regions. The arrow in the E<sub>T</sub><sup>miss</sup>/H<sub>T</sub><sup>lep</sup> variables indicates the minimum value of the requirement imposed in the final SR selection. The m<sub>&#8467;&#8467;</sub> and m<sub>T2</sub> distributions (right) have all the SR requirements applied. Background processes containing fewer than two prompt leptons are categorized as `Fake/nonprompt'. The category `Others' contains rare backgrounds from triboson, Higgs boson, and the remaining top-quark production processes listed in Table 1. The uncertainty bands plotted include all statistical and systematic uncertainties. The last bin includes overflow. The dashed lines represent benchmark signal samples corresponding to the Higgsino H&#771; and slepton &#8467;&#771; simplified models. Orange arrows in the Data/SM panel indicate values that are beyond the y-axis range.

<b>Kinematics 1</b> Kinematic distributions after the background-only fit showing the data as well as the expected background in the inclusive electroweakino SR&#8467;&#8467;-m<sub>&#8467;&#8467;</sub> [1, 60] (top) and slepton SR&#8467;&#8467;-m<sub>T2</sub><sup>100</sup> [100, &infin;] (bottom) signal regions. The arrow in the E<sub>T</sub><sup>miss</sup>/H<sub>T</sub><sup>lep</sup> variables indicates the minimum value of the requirement imposed in the final SR selection. The m<sub>&#8467;&#8467;</sub> and m<sub>T2</sub> distributions (right) have all the SR requirements applied. Background processes containing fewer than two prompt leptons are categorized as `Fake/nonprompt'. The category `Others' contains rare backgrounds from triboson, Higgs boson, and the remaining top-quark production processes listed in Table 1. The uncertainty bands plotted include all statistical and systematic uncertainties. The last bin includes overflow. The dashed lines represent benchmark signal samples corresponding to the Higgsino H&#771; and slepton &#8467;&#771; simplified models. Orange arrows in the Data/SM panel indicate values that are beyond the y-axis range.

<b>Kinematics 2</b> Kinematic distributions after the background-only fit showing the data as well as the expected background in the inclusive electroweakino SR&#8467;&#8467;-m<sub>&#8467;&#8467;</sub> [1, 60] (top) and slepton SR&#8467;&#8467;-m<sub>T2</sub><sup>100</sup> [100, &infin;] (bottom) signal regions. The arrow in the E<sub>T</sub><sup>miss</sup>/H<sub>T</sub><sup>lep</sup> variables indicates the minimum value of the requirement imposed in the final SR selection. The m<sub>&#8467;&#8467;</sub> and m<sub>T2</sub> distributions (right) have all the SR requirements applied. Background processes containing fewer than two prompt leptons are categorized as `Fake/nonprompt'. The category `Others' contains rare backgrounds from triboson, Higgs boson, and the remaining top-quark production processes listed in Table 1. The uncertainty bands plotted include all statistical and systematic uncertainties. The last bin includes overflow. The dashed lines represent benchmark signal samples corresponding to the Higgsino H&#771; and slepton &#8467;&#771; simplified models. Orange arrows in the Data/SM panel indicate values that are beyond the y-axis range.

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Version 3
Search for new phenomena in a lepton plus high jet multiplicity final state with the ATLAS experiment using $\sqrt{s}$ = 13 Tev proton-proton collision data

The ATLAS collaboration Aaboud, Morad ; Aad, Georges ; Abbott, Brad ; et al.
JHEP 09 (2017) 088, 2017.
Inspire Record 1597123 DOI 10.17182/hepdata.77491

A search for new phenomena in final states characterized by high jet multiplicity, an isolated lepton (electron or muon) and either zero or at least three $b$-tagged jets is presented. The search uses 36.1 fb$^{-1}$ of $\sqrt{s}$ = 13 TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider in 2015 and 2016. The dominant sources of background are estimated using parameterized extrapolations, based on observables at medium jet multiplicity, to predict the $b$-tagged jet multiplicity distribution at the higher jet multiplicities used in the search. No significant excess over the Standard Model expectation is observed and 95% confidence-level limits are extracted constraining four simplified models of $R$-parity-violating supersymmetry that feature either gluino or top-squark pair production. The exclusion limits reach as high as 2.1 TeV in gluino mass and 1.2 TeV in top-squark mass in the models considered. In addition, an upper limit is set on the cross-section for Standard Model $t\bar{t}t\bar{t}$ production of 60 fb (6.5 $\times$ the Standard Model prediction) at 95% confidence level. Finally, model-independent limits are set on the contribution from new phenomena to the signal-region yields.

129 data tables

The expected background and observed data with five jets in the different b-tag multiplicity bins for the 40 GeV jet pT threshold. The background shown is estimated by including all bins in the fit.

The expected background and observed data with five jets in the different b-tag multiplicity bins for the 40 GeV jet pT threshold. The background shown is estimated by including all bins in the fit.

The expected background and observed data with five jets in the different b-tag multiplicity bins for the 40 GeV jet pT threshold. The background shown is estimated by including all bins in the fit.

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