Public page of the EWK Z+2j analysis

The public PAS is available here.
The Paper version is available on the arxiv and submitted to JHEP.

* Candidate signal event display: Recorded data pp collision at √s = 7 TeV, run 163759, event 41507939 featuring a central di-muon system with invariant mass 90.2 GeV and a forward-backward di-jet system with invariant mass 1.4 TeV. The first display shows a 3D view of the event, while the second one shows a rφ display, where the trasverse momentum balance of the 2μ + 2jets system is visible.

* Figures from the paper in png format

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Figure 1: Representative diagrams for EW lljj production (for l=μ): VBF (left), bremsstrahlung (middle), and multiperipheral (right).

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Figure 2: Representative diagram for Drell–Yan production in association with two jets.

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Figure 3: Distribution of the absolute difference in the pseudorapidity of the tagging jets, ∆η_j1j2 = |η_j1 − η_j2 | (left) and the tagging jet p_T for both jets, j₁ and j₂ (right) for the DY μμjj, EW μμjj, and VBF Higgs boson production processes.

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Figure 4: The p_T^j₁ (left) and p_T^j₂ (right) distributions after applying the Zμμ selection and the TT jet tagging requirement TJ1. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panels show the ratio of data over the expected contribution of the signal plus background. The region between the two lines with the labels JES Up and JES Down shows the 1 σ uncertainty of the simulation prediction due to the jet energy scale uncertainty. The data points are shown with the statistical uncertainties.

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Figure 5: The absolute difference in the pseudorapidity of the two tagging jets (left), and the dimuon p_T (right) after the Zμμ selection and the tagging jet requirement TJ1. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panels show the ratio of data over the expected contribution of the signal plus back- ground. The region between the two lines with the labels JES Up and JES Down shows the 1 σ uncertainty of the simulation prediction due to the jet energy scale uncertainty. The data points are shown with the statistical uncertainties.

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Figure 6: The H_T distribution of the three leading soft track jets in the pseudorapidity interval between the tagging jets with p_T^j₁,j₂ > 65, 40 GeV in DY Zjj events for dielectron (left) and dimuon (right) channels. The bottom panels show the corresponding data/MC ratios. The data points are shown with the statistical uncertainties.

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Figure 7: Average H_T of the three leading soft track jets in the pseudorapidity gap between the tagging jets for p_T^j₁,j₂ > 65, 40 GeV as a function of the dijet invariant mass (left) and the dijet ∆η_j1j2 separation(right) for both the dielectron and dimuon channels in DY Zjj events. The data points and the points from simulation are shown with the statistical uncertainties.

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Figure 8: Average number of jets with p_T > 40 GeV as a function of the their total H_T in Z plus at least one jet events (left) and average cos ∆φ_j1j2 as a function of the total H_T in DY Zjj events (right). The data points and the points from simulation are shown with the statistical uncertainties.

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Figure 9: Average number of jets with p_T > 40 GeV as a function of ∆η_j1j2 (left) and average cos∆φ_j1j2 as a function of ∆η_j1j2 separation (right) in DY Zjj events. The data points and the points from simulation are shown with the statistical uncertainties.

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Figure 10: The m_j1j2 distribution after the Zμμ, TJ1, and YZ selections. The expected contributions from the dominant DY μμjj background and the EW μμjj signal processes are evaluated from a fit, while the contributions from the small tt and diboson backgrounds are estimated from simulation.The solid line with the label “EW only” shows the m_j1j2 distribution for the signal alone. The bottom panel shows the ratio of data over the expected contribution of the signal plus background. The region between two lines, with the labels JES Up and JES Down, shows the 1 σ uncertainty due to the jet energy scale uncertainty. The data points are shown with the statistical uncertainties.

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Figure 11: The BDT output distributions for the μ+μ− channel (left) and the e+e− channel (right) after applying the Zμμ and Zee selection criteria, respectively, with the tagging jet requirement TJ1. The expected contributions from the signal and background processes are evaluated from simulation. The solid line with the label “EW only” shows the BDT output distribution for the signal alone. The bottom panels show the ratio of data over the expected contribution of the signal plus background. The region between the two lines, with the labels JES Up and JES Down, shows the 1 σ uncertainty of the simulation prediction due to the jet energy scale uncertainty. The data points are shown with the statistical uncertainties.

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Figure 12: The BDT output distributions for the μ+μ− (left) and e+e− (right) channels after the respective Zμμ and Zee selections and the tagging jet requirement TJ1. The expected contributions from the dominant DY lljj background and the EW lljj signal processes are evaluated from the fit. The contributions from the small tt and diboson backgrounds are estimated from simulation. The solid line with the label “EW only” shows the BDT output distribution for the signal alone. The bottom panels show the significance observed in data (histogram) and expected from simulation (solid purple line). The dashed blue line shows the background modeling uncertainty. The calculation of the significance and background modeling uncertainty are explained in the text. The data points are shown with the statistical uncertainties.

* Other figures from the PAS

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Figure 6: Left: the dimuon p_T after selections ”Zμμ” and (1) for the μ+μ− mode. Right: the m_j1j2 after selections ”Zμμ”, (1) and (2) for the μ+μ− mode. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panel shows the ratio of data over the expected contribution of the signal plus backgrounds along with the statistical uncertainties.

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Figure 7: The p_T^j₁ (left) and p_T^j₂ (right) after selections ”Z_ee” and (1) for the e+e− mode. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panel shows the ratio of data over the expected contribution of the signal plus backgrounds along with the statistical uncertainties.

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Figure 8: The |η_j| and |y*| after selections ”Z_ee” and (1) for the e+e− mode. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panel shows the ratio of data over the expected contribution of the signal plus backgrounds along with the statistical uncertainties.

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Figure 9: The absolute difference in the pseudorapidity of the two tagging jets (left) and the difference in the azimuthal angles of two tagging jets (right) after selections ”Z_ee” and (1) for the e+e− mode. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panel shows the ratio of data over the expected contribution of the signal plus backgrounds along with the statistical uncertainties.

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Figure 10: Left: the dielectron p_T after selections ”Z_ee” and (1) for the e+e− mode. Right: the m_j1j2 after selections ”Z_ee”, (1) and (2) for the e+e− mode. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panel shows the ratio of data over the expected contribution of the signal plus backgrounds along with the statistical uncertainties.

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Figure 18: The gluon likelihood of the first (left) and second (right) tagging jets in the di-electron channel after the ”Z_ee” selection and requirement p_T^j₁ > 65 GeV, p_T^j₂ > 40 GeV, |eta_j| < 3.6. The expected contributions from the signal and background processes are evaluated from simulation. The bottom panel shows the ratio of data over the expected contribution of the signal plus backgrounds along with the statistical uncertainties.

-- MariaToms - 18-Dec-2012