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ATLAS Stand-Alone Event Displays

The event displays below are stand-alone event displays from 2010 - 2012 proton-proton collision data and are approved to be shown by ATLAS speakers at conferences and similar events. Click on the thumbnail images to access full-size displays.

The main Event Display Public Page gives an overview on all available public event displays.

If you wish to use these event displays for other purposes than presentations of ATLAS results, please see the copyright statement.

Events with pile-up

2 vertices

An early 7 TeV collision event with two reconstructed primary vertices (pileup), collected in the first 7 TeV fill on 30 March 2010. The longitudinal distance between the vertices amounts to approximately 2.5 cm.

4 vertices

Event with four reconstructed primary vertices, consistent with an event with four primary proton-proton collisions in the same beam-crossing. The transverse and longitudinal impact parameters of the four vertices are consistent with the luminous region of the colliding beams. The z-coordinates of the vertices are (from left in the plot to right, in mm) −32.1, −22.9, 4.6, 18.8.

7 vertices

A collision event from the first 2011 fill with stable beams, which were declared at 18:04 on Sunday 13 March.

11 vertices

A candidate Z boson event in the dimuon decay with 11 reconstructed vertices. This event was recorded on April 24th and is typical for the 2011 environment with high pileup. For this display the track pT threshold is 0.4 GeV and all tracks are required to have at least 2 Pixel and 7 SCT hits. The vertices shown are reconstructed using tracks with pT greater than 0.4 GeV. The smallest separation between any two of them is 3.2+-0.2 mm.The invariant mass of the two muons is 93.4 GeV.

20 vertices

A candidate Z boson event in the dimuon decay with 20 reconstructed vertices. This event was recorded on September 14th and is typical for the 2011 environment with high pileup after the beta* was reduced to 1m (in the Technical Stop in Sept 2011). For this display the track pT threshold is 0.4 GeV and all tracks are required to have at least 2 Pixel and 7 SCT hits. The vertices shown are reconstructed using tracks with pT greater than 0.4 GeV. The reconstructed vertex error elipses are shown scaled up by a factor of 20 so that they are visible.

2012 Z->mu mu event with high pileup

A candidate Z boson event in the dimuon decay with 25 reconstructed vertices. This event was recorded on April 15th 2012 and demonstrates the high pileup environment in 2012 running (when the beta* was reduced to 0.6m). For this display the track pT threshold is 0.4 GeV and all tracks are required to have at least 3 Pixel and 6 SCT hits. The vertices shown are reconstructed using tracks with pT greater than 0.4 GeV, but with tighter requirements on the number of hits on the tracks than in the 2011 reconstruction.

J/ψ events

J/ψ → μμ

This event display shows a candidate event of the type J/ψ → μμ

J/ψ → ee

Event display of a candidate for a J/ψ → e+e- decay collected on August 4, 2010 in 7 TeV pp collisions. Events with two reconstructed opposite charge electrons passing tight identification criteria were selected (see ATLAS-PERF-2010-04-001 for more information on electron reconstruction and identification). The invariant mass of the J/ψ candidate is 3.17 GeV. Further event properties:
  • e+ : ET = 7.52 GeV, η = 0.080, φ = -0.835
  • e- : ET = 12.44 GeV, η = 0.400, φ = -0.767
  • J/ψ candidate : M = 3.17 GeV, pT = 19.96 GeV

W and Z decays

W decays to leptons

W → e or μ + ν

Candidate for W→μν decay, collected on 1 April 2010.
Event properties: pT+) = 29 GeV
η(μ+) = 0.66
ETmiss= 24 GeV
MT = 53 GeV

Candidate for W→eν decay, collected on 5 April 2010.
Event properties: pT(e+) = 34 GeV
η(e+) = -0.42
ETmiss= 26 GeV
MT = 57 GeV
Another candidate for W→eν decay, collected on 10 April 2010.
Event properties: pT(e+) = 23 GeV
η(e+) = -0.64
ETmiss= 31 GeV
MT = 55 GeV
Another candidate for W→μν decay, collected on 12 April 2010.
Event properties: pT-) = 40 GeV
η(μ-) = 1.1
ETmiss= 41 GeV
MT = 83 GeV
A candidate for W→μν decay, collected on 16 May 2010.
Event properties: pT-) = 22 GeV
η(μ-) = 2.0
ETmiss= 51 GeV
MT = 61 GeV
Three jets (anti-kt algorithm, R=0.4) with jet ET above 15 GeV, all three have calibrated ET>40 GeV; the highest-ET jet contains a muon candidate, as can be seen in the event picture.


W → τν

A candidate for a W → τν decay, with a hadronically decaying tau, collected on 24 May 2010.
Event properties:
pT(τ) = 29 GeV
ETmiss = 39 GeV
Δφ(τ, ETmiss ) = 3.1
mT = 68 GeV

No additional object (electron, muon or jet) was found in the event.

W decay with a photon

Candidate for a W->μν decay, with the W boson produced in association with a photon, collected on 28 October 2010. The transverse mass of the W boson is 65 GeV. The muon and the photon are well isolated.
Further event properties: PT(mu) = 38 GeV
PT(gamma) = 39 GeV
ETmiss = 30 GeV

Z decays to leptons

Z → e+e- or μ+μ-

Candidate for Z→ee decay, collected on 9 May 2010.
Event properties: ET(e+) = 40 GeV
η(e+) = -0.38
ET(e-) = 45 GeV
η(e-) = 0.21
mee = 89 GeV
Candidate for Z→μμ decay, collected on 10 May 2010.
Event properties: pT+) = 45 GeV
η(μ+) = 2.2
pT-) = 27 GeV
η(μ-) = 0.7
mμμ = 87 GeV



Z → τ+τ-

A candidate for a Z→ττ decay, with one muonically and one hadronically decaying tau, collected on 3 August 2010.
Event properties:
pT(μ) = 18 GeV
pTvish) = 26 GeV
mvis(μ , τh) = 47 GeV
mT(μ , ETmiss) = 8 GeV
ETmiss = 7 GeV
The hadronic tau candidate has three well identified tracks.
The muon and tau candidate have opposite sign reconstructed charges.
No additional object (electron, muon or jet) was reconstructed in this event.

Z decay with a photon

Candidate for a Z->ee decay, with the Z boson produced in association with a photon, collected on 28 October 2010. The Z boson invariant mass is 91 GeV. The two electrons and the photon are well isolated.
Further event properties: PT(e+) = 51 GeV
PT(e-) = 37 GeV
PT(gamma) = 30 GeV

Z decay with large missing ET

Candidate event with a Z decay to muon pairs, recoiling against missing-ET. The muon candidates have transverse momenta of 50 and 126 GeV and a dimuon invariant mass of 94 GeV; the missing ET is measured to be 161 GeV.

Z decay to leptons, produced in association with jets

Candidate for Z→μμ decay, with the Z produced in association with three jets, collected on 10 May 2010.
In the xy projection, the 144 GeV transverse momentum of the Z boson is especially apparent. The muon transverse momenta are 96 GeV and 68 GeV, and their invariant mass is 79 GeV. The harder muon has left a significant energy deposit (see lego-plot projection), presumably through bremsstrahlung; this is not included in the standard Z mass calculation. The jet transverse energies are 168, 105, and 45 GeV.

WW, ZZ and WZ decays

WW to two charged leptons

WW → eνμν

Event display of a WW candidate event in the eμ final state (special version for Peter Ginter book, event properties in ATLAS-CONF-2011-015).

Probably a Drell-Yan or WW event with the highest eμ pair invariant mass (see ATLAS-CONF-2011-109).

ZZ to four charged leptons

ZZ → μμμμ

Event with four muons, compatible with the hypothesis of Z pair production where one of the Z bosons is off-shell. M12 = 90.6 GeV, M34 = 47.4 GeV.
2D event display of a 4μ candidate event with m4l=124.6 GeV. The masses of the lepton pairs are 89.7 GeV and 24.6 GeV (Better version of fig. 10b in ATLAS-CONF-2011-162).
3D event display of a 4μ candidate event with m4l=124.6 GeV. The masses of the lepton pairs are 89.7 GeV and 24.6 GeV (Better version of fig. 10a in ATLAS-CONF-2011-162).
Event display of a 4μ candidate event with m4l = 145.8 GeV. The masses of the lepton pairs are 94.3 GeV and 29.7 GeV respectively.

ZZ → eeμμ

Event display of a eeμμ candidate event with m4l = 209.7 GeV. The masses of the lepton pairs are 85.9 and 85.5 GeV respectively (Persint version of fig. 7 in ATLAS-CONF-2011-131).
Event display of a 2e2μ candidate event with m4l=124.3 GeV. The masses of the lepton pairs are 76.8 GeV and 45.7 GeV. (Better version of fig. 11b in ATLAS-CONF-2011-162).

W+Z double leptonic decay events

WZ → eνμμ

Candidate for a WZ → eνμμ decay, collected on 7 October 2010. The invariant mass of the two muons is 96 GeV. The transverse mass of the potential W boson is 57 GeV.
Further event properties:
PT+) = 65 GeV
PT-) = 40 GeV
PT(e) = 64 GeV
ETmiss = 21 GeV

WZ → μνμμ

Candidate for a WZ → μνμμ decay, collected on 25 October 2010. The invariant mass of the two muons attributed to the Z is 92 GeV. The transverse mass of the potential W boson is 88 GeV.
Further event properties:
Z candidate:
PT-) = 60 GeV
PT+) = 35 GeV
W candidate:
PT-) = 40 GeV
ETmiss = 55 GeV (indicated by a blue line in the display)

Heavy quark events

b-jet events

This event display shows a b-jet candidate with a transverse momentum of 19 GeV, measured at the electromagnetic scale and reconstructed with the AntiKt4 jet algorithm. Four tracks with at least one hit in the innermost layer of the pixel detector (among other requirements) were used for the identification, which relied on two tagging algorithms. An algorithm (JetProb) based on computing the compatibility of the tracks with the hypothesis that they all originate from the primary event vertex gives this probability as 9e-6. An algorithm (SV0) explicitly reconstructing the secondary decay vertex computes the following properties of the secondary vertex: a 50-sigma separation in 3D from the primary vertex (6 mm in the transverse plane) and a mass of 3.9 GeV. The location of the secondary vertex is highlighted by a dashed red box (the box size is unrelated to the reconstruction uncertainties). The event contains three jets with a transverse momentum higher than 15 GeV (EM scale). Two of them are just visible on the top left drawing because of the projection.

Top events

Event display of a top pair e-mu dilepton candidate with two b-tagged jets. The electron is shown by the green track and calorimeter cluster in the 3D view, and the muon by the long red track intersecting the muon chambers. The two b-tagged jets are shown by the purple cones, whose sizes are proportional to the jet energies. The inset shows the XY view of the vertex region, with the secondary vertices of the two b-tagged jets indicated by the orange ellipses.
Event display of a top pair e-mu dilepton candidate with two b-tagged jets. The electron is shown by the green track pointing to a calorimeter cluster, the muon by the long red track intersecting the muon chambers, and the missing ET direction by the dotted line on the XY view. The secondary vertices of the two b-tagged jets are indicated by the orange ellipses on the zoomed vertex region view.
Event display of an electron plus jets candidate. The electron is shown as the yellow upward pointing track pointing towards the green cluster, and as the red-circled tower in the eta-phi lego plot. The direction of the missing transverse energy is shown by the dotted line in the r-φ view. The two zoomed vertex views show the secondary vertex from the b-tagged jet (top) and the two primary vertices from the high pT interaction (to the left on the lower display) and a second pileup interaction (on the right). See also ATLAS-CONF-2010-063.
Event display of an ee dilepton candidate. The two electrons are picked out in black. See also ATLAS-CONF-2010-063.
Event display of an e-mu dilepton candidate. The isolated muon track is shown in red (left-hand side), the isolated electron is shown as red track pointing to a green cluster. The b-tagged jet is marked as a blue circle in the eta-phi lego plot, and the muon (red) and electron (green) tracks are also indicated. The direction of the missing transverse energy is shown as a dashed line in the eta-phi lego plot. The zoom of the vertex region shows the three tracks from the b-tag secondary vertex in blue. See also ATLAS-CONF-2010-063.
Event display of a tau-mu dilepton candidate. The muon track is shown in red, the (3-prong) tau candidate is shown at the lower right in the x-y projections. The muon has positive electric charge, the tau negative. The tau candidate has multivariate discriminant values of BDTj=0.98 and BDTe=0.86. The analysis used to select the event is described in ATLAS-CONF-2011-119, including the explanation of these BDT variables. The b-tagged jet is indicated by the blue tracks in the vertex-region zoomed view. This jet is the leading jet in the event with a pT of 144 GeV, and an SV0 decay length significance of 22.9. The estimated signal-to-background ratio for the selection employed is above 3. Further event properties:
pThad) = 53 GeV
pT(μ) = 20 GeV
ETmiss = 39 GeV
Njet(pT > 25 GeV) = 3, including the τ-jet

Multi-Jet events

High mass dijet events

 NEW  High mass central dijet event with the highest-pT jet collected by the end of April 2012: two central high-pT jets have an invariant mass of 3.62 TeV and the highest pT jet has pT of 1.96 TeV. A track pT cut of 0.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 1.96 TeV, η = -0.07, φ = -2.68
  • 2nd jet: pT = 1.65 TeV, η = 0.17, φ = 0.48
  • Missing ET = 318 GeV, φ = 0.43
  • Sum ET = 3.81 TeV
Event collected on 9 April 2012.
 NEW  High mass central dijet event collected by the end of April 2012: two central high-pT jets have an invariant mass of 3.65 TeV and the highest pT jet has pT of 1.72 TeV. A track pT cut of 0.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 1.72 TeV, η = -0.04, φ = -2.68
  • 2nd jet: pT = 1.50 TeV, η = 0.64, φ = 1.70
  • 3rd jet: pT = 0.22 TeV, η = 0.28, φ = -2.13
  • Missing ET = 29 GeV, φ = 0.50
  • Sum ET = 3.91 TeV
Event collected on 10 April 2012.
 NEW  The highest mass central dijet event collected by the end of April 2012: two central high-pT jets have an invariant mass of 4.23 TeV and the highest pT jet has pT of 1.36 TeV. A track pT cut of 0.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 1.36 TeV, η = -1.02, φ = 3.01
  • 2nd jet: pT = 1.29 TeV, η = 1.06, φ = 0.09
  • Missing ET = 125 GeV, φ = -0.44
  • Sum ET = 3.33 TeV
Event collected on 14 April 2012.

The highest mass central dijet event and the highest-pT jet collected by the end of October 2010: two central high-pT jets have an invariant mass of 2.6 TeV and the highest pT jet has pT of 1.3 TeV.
  • 1st jet (ordered by pT): pT = 1.3 TeV, η = 0.2, φ = 2.8
  • 2nd jet: pT = 1.2 TeV, η = 0.0, φ = -0.5
  • Missing ET = 42 GeV, φ = 1.5
  • Sum ET = 2.2 TeV
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 24 October 2010.
The highest mass dijet event collected by the end of October 2010: the two highest-pT jets have an invariant mass of 3.7 TeV.
  • 1st jet (ordered by pT): pT = 670 GeV, η = 1.9, φ = -0.5
  • 2nd jet: pT = 610 GeV, η = -1.6, φ = 2.8
  • Missing ET = 47 GeV, φ = 0.0
  • Sum ET = 1.3 TeV
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 8 October 2010.
The highest mass dijet event collected by the end of August 2010: the two highest-pT jets have an invariant mass of 3.1 TeV.
  • 1st jet (ordered by pT): pT = 520 GeV, η = -1.4, φ = -2.0
  • 2nd jet: pT = 460 GeV, η = 2.2, φ = 1.0
  • 3rd jet: pT = 130 GeV, η = -0.3, φ = 1.2
  • 4th jet: pT = 50 GeV, η = -1.0, φ = -2.9
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 24 August 2010.
A high mass central dijet event: two central high-pT jets with invariant mass 1.9 TeV. A track pT cut of 2.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 890 GeV, y = -0.6, φ = -2.8
  • 2nd jet: pT = 760 GeV, y = 0.6, φ = 0.3
  • 3rd jet: pT = 30 GeV, y = 1.5, φ = 0.4
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 8 August 2010.
A high mass central dijet event: two central high-pT jets with invariant mass 1.8 TeV. A track pT cut of 2.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 930 GeV, y = 0.5, φ = -1.7
  • 2nd jet: pT = 720 GeV, y = -0.3, φ = 1.5
  • 3rd jet: pT = 130 GeV, y = 1.9, φ = 0.9
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 31 July 2010.
A high mass dijet event: two high-pT jets with invariant mass 2.8 TeV. A track pT cut of 2.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 310 GeV, y = -2.0, φ = -0.2
  • 2nd jet: pT = 280 GeV, y = 2.5, φ = 2.9
  • 3rd jet: pT = 14 GeV, y = -0.9, φ = -1.0
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 5 August 2010.
Event with a high mass dijet system: the invariant mass of the two highest-pT jets is 2.55 TeV. The highest pT jet has a pT of 420 GeV, and an eta of -1.51, the second leading jet has pT of 320 GeV and an eta of 2.32. Jet momenta are calibrated according to the "EM+JES" scheme. No other jets are found with pT above 20 GeV. Event collected on 4 July 2010.

High pT leading jet

Event with a very high pT leading jet: the highest pT jet has a pT of 1.12 TeV, and an eta of 0.33. the second leading jet has pT of 480 GeV and an eta of -0.93. Two further jets have pT above 80 GeV. Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 18 July 2010.

4 jets

Event with four reconstructed hadronic jets with calibrated pT > 100 GeV. The highest pT jet has a calibrated jet pT of 805 GeV, and an eta of -0.43. The invariant mass of the two leading jets is 1.55 TeV. Event collected on 4 July 2010.
Event with four reconstructed hadronic jets. The four jets have a calibrated pT > 50 GeV, and are found with the anti-kt algorithm with R=0.6. The highest pT jet has a calibrated jet pT of 108 GeV. Event collected on 6 April 2010.
Event with four reconstructed hadronic jets. The four jets have a calibrated pT > 50 GeV, and are found with the anti-kt algorithm with R=0.6. The highest pT jet has a calibrated jet pT of 144 GeV. Event collected on 10 April 2010.
Event with four reconstructed hadronic jets and a reconstructed muon. The four jets have a calibrated pT > 50 GeV, and are found with the anti-kt algorithm with R=0.6. The highest pT jet has a calibrated jet pT of 239 GeV. Event collected on 10 April 2010.

6 jets

An event with 6 jets taken on 4 April 2010. The jets have calibrated transverse momenta between 30 GeV and 70 GeV and are well separated in the detector. Note that the energies given in the lego plot are yet uncalibrated, that is, they are lower than the calibrated energies.
A multi-jet event with four jets with pT above 200 GeV (six jets above 100 GeV). The high pT leading jet balances five lower pT jets in the transverse plane. A track pT cut of 2.5 GeV has been applied for the display.
  • 1st jet (ordered by pT): pT = 810 GeV, y = -0.2, φ = -2.8
  • 2nd jet: pT = 240 GeV, y = -1.3, φ = -0.3
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 10 August 2010.

8 jets

The highest jet multiplicity event collected by the end of October 2010, counting jets with pT greater than 60 GeV: this event has eight.
  • 1st jet (ordered by pT): pT = 290 GeV, η = -0.9, φ = 2.7
  • 2nd jet: pT = 220 GeV, η = 0.3, φ = -0.7
  • Missing ET = 21 GeV, φ = -1.9
  • Sum ET = 890 GeV
Jet momenta are calibrated according to the "EM+JES" scheme. Event collected on 5 October 2010.


Major updates:
-- MichaelHauschild - 08-Aug-2012

Responsible: MichaelHauschild
Subject: public

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Topic revision: r2 - 2012-08-09 - MichaelHauschild
 
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