# Event Displays from Run 2 physics analyses

The event displays below are approved to be shown by ATLAS speakers at conferences and similar events. Click on the thumbnail images to access full-size displays. If you wish to use these event displays for other purposes than presentations of ATLAS results, please see the copyright statement.

The first section of this page shows displays of candidates selected by Run 2 physics analyses. This is not an exhaustive list. Event displays included in conf-notes or papers which do not appear on this page will appear in the list of figures of the corresponding public document.

The second section of this page shows event displays which are not included in publicly available documents.

## Event displays included in publications or conference notes

### Higgs

#### 2e2μ ZH candidate recorded in 2018 - ATLAS-CONF-2019-025

Event display of a 2e2μ ZH candidate. The invariant mass of the 4-lepton system is 122.5 GeV, and the leading (subleading) dilepton mass is 91.4 (20.4) GeV. The two leading electrons are represented by green tracks and green EM calorimeter deposits with pT = 21.6 and 119.8 GeV, and the subleading muons are indicated by two red tracks with pT = 34.1 and 42.9 GeV. Recoiling against the four lepton candidate in the left hemisphere is a dimuon pair in the right hemisphere indicated by the red tracks with pT = 138.8 and 41.5 GeV and an invariant mass of 91.5 GeV. The ETmiss is 19.3 GeV.

#### 2μ2e ZH candidate recorded in 2018 - ATLAS-CONF-2019-025

Event display of a 2μ2e candidate. The invariant mass of the 4-lepton system is 121.9 GeV, and the leading (subleading) dilepton mass is 86.5 (25.7) GeV. The two leading muons are indicated by two red tracks with pT = 100.4 and 83.9 GeV, and the two subleading electrons are represented by green tracks and green EM calorimeter deposits with pT = 13.1 and 17.5 GeV. No jet above pT = 30 GeV is observed. The dotted white line is the ETmiss with a value of 240.3 GeV. It is back-to-back with the four lepton candidate, pTH = 181.1 GeV, φ4l = 1.53, φ ETmiss = -1.57. This 0-jet event is consistent with a VH candidate, with V=Z and Z → νν or with V=W and W → lν where the charged lepton is outside the detector acceptance (or not reconstructed).

#### 4μ ttH-Lep-enriched candidate recorded in 2017 - ATLAS-CONF-2019-025

Event display of a 4μ ttH-Lep-enriched candidate. The invariant mass of the 4-lepton system is 124.4 GeV, and the leading (subleading) dilepton mass is 89.3 (33.0) GeV. The two leading muons are indicated by two red tracks with pT = 15.4 and 45.6 GeV, and the two subleading muons are represented by red tracks with pT = 9.7 and 21.3 GeV. There is an additional electron represented by a green track and green EM calorimeter deposit with pT = 77.5 GeV. There are four jets in this event with pT= 76.7, 42.0, 30.7 and 30.5 GeV, where the lowest pT jet has the tightest level b-tag at 60% efficiency. The ETmiss has a value of 47.0 GeV and is given by the dotted white line. The S/B for the ttH-Lep-enriched category is about 30.

#### Candidate ttH eμτhad eventin the 2ℓ1τhad category recorded in 2016 - Phys. Rev. D 97 (2018) 072003

Event display for a ttH candidate eμτhad event in the 2ℓ1τhad category. The blue track is the selected electron; the red track is the selected muon; and the grey cone is the τhad candidate. The azure cone is the selected b-tagged jet, and the four yellow cones are the non-b-tagged jets. Green and yellow bars indicate energy deposits in the electromagnetic (liquid argon) and hadronic (tile) calorimeters, respectively. The transverse momenta of the leptons are pTe-=68 GeV, pTμ-=72 GeV, and pTτ+=103 GeV. The transverse momenta of the jets are pTb-jet=83 GeV, pTnon b-jet=125, 37, 37, 29 GeV.

#### Candidate H→bb decay event with two b-tag jets and no lepton recorded in 2015 - ATLAS-CONF-2017-041

Event display from Evidence for the H→bb decay with the ATLAS detector.

A 2-tag, 2-jet, 0-lepton event within the signal-like portion of the high pTV region BDTVH (Run 284213, Event 1927020336) is shown. The ETMiss, shown as a white dashed line, has a magnitude of 294.3 GeV. The two central high-pT b-tagged jets are shown as green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively. The dijet invariant mass of 136.9 GeV. Tracks with pT above 1 GeV are shown.Tracks in both jets form signatures compatible with the decay of a b-hadron. The BDTVH output is 0.67. The excerpt shows three vertices and their associated tracks (with a pT cut of 1.5 GeV): the yellow circle represents the primary vertex and the two light blue circles the two secondary vertices compatible with the presence of b-decays.

#### Candidate H→bb decay event with two b-tag jets and no lepton recorded in 2015 - ATLAS-CONF-2017-041

Event display from Evidence for the H→bb decay with the ATLAS detector.

A 2-tag, 2-jet, 0-lepton event within the signal-like portion of the high pTV region BDTVH (Run 284213, Event 1927020336) is shown. The ETMiss, shown as a white dashed line, has a magnitude of 294.3 GeV. The two central high-pT b-tagged jets are shown as green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively. The dijet invariant mass of 136.9 GeV. Tracks in both jets form signatures compatible with the decay of a b-hadron. The BDTVH output is 0.67.

#### Candidate H→bb decay event with two b-tag jets and one electron recorded in 2016 - ATLAS-CONF-2017-041

Event display from Evidence for the H→bb decay with the ATLAS detector.

A 2 b-tag, 2-jet, 1-electron event within the most signal-like portion of the BDTVH output distribution is shown (Run 303499, Event 2810362531). The electron is shown as a red track with a large energy deposit in the electromagnetic calorimeter, corresponding to light green bars, and has a pT of 151 GeV. The ETmiss, shown as a white dashed line, has a magnitude of 320 GeV. These correspond to a pTV of 450 GeV. The two central high-pT b-tagged jets are represented by light yellow cones. They contain the green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively, and they have an invariant mass of 124 GeV.

#### Candidate H→bb decay event with two b-tag jets and two muons recorded in 2016 - ATLAS-CONF-2017-041

Event display from Evidence for the H→bb decay with the ATLAS detector.

A 2 b-tag, 2-jet, 2-muon event within the most signal-like portion of the BDTVH output distribution is shown (Run 309440, Event 990753168). The event stems from the high pTV analysis region. Muons are shown as red tracks. Two of them form an invariant mass of 88.7 GeV, compatible with a Z boson, while a third one is found within Δ R of 0.4 of a jet and utilised in the muon-in-jet correction. The two central high-pT b-tagged jets are represented by light yellow cones. They contain the green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively, and they have an invariant mass of 123.3 GeV. The value of pTV is 204 GeV.

#### Candidate H→μμ decay recorded in 2015 - arXiv:1705.04582.

Event display from Search for the dimuon decay of the Higgs boson in pp collisions at √s = 13 TeV with the ATLAS detector. - arXiv:1705.04582 (This event display is not yet linked onto the the paper web page)

#### Candidate heavy Higgs boson decaying to two tau leptons, in association with a b-jet - JHEP 01 (2018) 055.

Event display associated to the publication Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36/fb of pp collisions at sqrt(s) = 13 TeV with the ATLAS detector

Display of event 264472429 of run 302393 showing a candidate of a heavy Higgs particle produced in association with a b-jet (red jet cone) with pT(b-jet)=47 GeV. The decay is into a pair of oppositely charged tau leptons (blue jet cones) with pTtau1=292 GeV and pTtau2=275 GeV. Both tau leptons decay hadronically into three charged particles. The 2nd tau (tau2) also has significant energy deposition in the electromagnetic calorimeter indicating a neutral pion decay into two photons. The direction of missing transverse momentum ETmiss of 33 GeV is indicated by the white dotted line in the transverse plane view. The total transverse mass mTtot = sqrt( (pTtau1 + pTtau2+ETmiss)2 - (pTtau1 + pTtau2 + ETmiss)2) = 591 GeV, where pTtau1, pTtau2 and ETmiss are vectors in the transverse plane. Tracks with momentum larger than 4 GeV are shown as green lines.

#### Candidate Higgs boson produced in association with a pair of top quarks and decaying to two photons - arXiv:1806.00425

Event display associated to the publication Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

Visualization of a data event from the tt̄H(γγ) Had BDT bin with the largest signal over background ratio. The event contains two photon candidates, with a diphoton mass of 125.4 GeV. In addition, six jets are reconstructed using the anti-kt algorithm and R=0.4, including one jet that is b-tagged using a 77% efficiency working point. The photons correspond to the green towers in the electromagnetic calorimeter, while the jets (b-jets) are shown as yellow (blue) cones.

#### Candidate Higgs boson produced in association with a pair of top quarks and decaying to two photons - arXiv:1806.00425

Event display associated to the publication Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

Visualization of a data event from the tt̄H(γγ) Lep BDT bin with the highest signal over background ratio. The event contains one electron candidate with pT = 33.9 GeV and two photon candidates with a diphoton mass of 125.2 GeV. In addition, four jets are reconstructed using the anti-kt algorithm and R=0.4, including one jet that is b-tagged using a 77% efficiency working point. The electron is represented as a green line leading to green deposits in the electromagnetic calorimeter. The photons correspond to the remaining green towers in the electromagnetic calorimeter, while the jets (b-jets) are shown as yellow (blue) cones.

#### Candidate Higgs boson produced in association with a pair of top quarks and decaying to two photons - arXiv:1806.00425

Event display associated to the publication Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

Visualization of a data event from the tt̄H(γγ) Had BDT bin with the largest signal over background ratio. The event contains two photon candidates, with a diphoton mass of 124.3 GeV. In addition, six jets are reconstructed using the anti-kt algorithm and R = 0.4, including two jets that are b-tagged using a 77% working point. The photons correspond to the green towers in the electromagnetic calorimeter, while the jets (b-jets) are shown as yellow (blue) cones.

#### Candidate Higgs boson produced in association with a pair of top quarks and decaying to two photons - arXiv:1806.00425

Event display associated to the publication Observation of Higgs boson production in association with a top quark pair at the LHC with the ATLAS detector

Visualization of a data event from the tt̄H(γγ) Lep BDT bin with the highest signal over background ratio. The event contains one muon candidate with pT = 65.0 GeV and two photon candidates with a diphoton mass of 126.3 GeV. In addition, five jets are reconstructed using the anti-kt algorithm and R = 0.4, including one jet that is b-tagged using a 77% working point. The muon is represented as a red track passing through the detector. The photons correspond to the remaining green towers in the electromagnetic calorimeter, while the jets (b-jets) are shown as yellow (blue) cones.

### Standard Model

#### Photon+jets candidate event recorded in 2015 - arXiv:1701.06882

Display of event 1653294681 in run 282992. The event contains a photon candidate with ETγ=0.90 TeV, ηγ=2.0 and φγ=2.9 rad. The energy deposits associated to the photon candidate in the LAr calorimeter (green shaded areas) are represented by yellow boxes. The jets reconstructed with the anti-kt algorithm using R=0.4 with pT > 50 GeV are represented by the overlaid white cones. In the lego plot the photon (jet) candidate is represented by the yellow (white) coloured tower.

#### Photon+jets candidate event recorded in 2015 - arXiv:1701.06882

Event display from Measurement of the cross section for inclusive isolated-photon production in pp collisions at sqrt(s) = 13 TeV using the ATLAS detector.

Display of event 3035596523 in run 283429. The event contains a photon candidate with ETγ=1.3 TeV, ηγ=-0.3 and φγ=3.1 rad. The energy deposits associated to the photon candidate in the LAr calorimeter (green shaded areas) are represented by yellow boxes. The jets reconstructed with the anti-kt algorithm using R=0.4 with pT > 50 GeV are represented by the overlaid white cones. In the lego plot the photon (jet) candidate is represented by the yellow (white) coloured tower.

### Top

#### Candidate top-Z-q recorded in 2016 - ATLAS-CONF-2017-052

Event display for one tZq candidate event from the data collected in 2016. The event was collected during the run 303304 and has ONN = 0.94. This event contains one electron and two muons. The electron has pT(e) = 144 GeV, and the two muons have pT1) = 159 GeV and pT2) = 41 GeV. The forward jet has pT = 252 GeV. The b-jet has pT = 68 GeV. Muon tracks are shown in red, electromagnetic clusters in yellow, inner detector tracks in grey (Run=303304, Event=4100335171).

#### Four-top candidate event with 13 jets recorded in 2015 - ATLAS-CONF-2016-020

Event display from Search for four-top-quark production in final states with one charged lepton and multiple jets using 3.2 fb−1 of proton-proton collisions at sqrt(s) = 13 TeV with the ATLAS detector at the LHC.

An event display of the reconstructed event with the highest HThad = 2762 GeV found in the signal region data sample. The event contains in total 13 jets, out of which four are b-tagged jets (magenta cones) and the rest are light-flavour jets (white cones), and one muon (cyan line). The five leading jets have transverse momenta pT = 1234, 602, 211, 138, 120 GeV, respectively, and the third and fifth jets are b-tagged. The missing transverse momentum (red dotted line) amounts to 288 GeV and the muon pT is 53 GeV. The two-dimensional histogram displays the energy deposits of the objects as a function of η and φ, as calculated from the calorimeter cells.

### Exotics (Full Run2 event displays page from the exotics group).

#### Monojet event recorded in 2016 - ATLAS-CONF-2017-060

Event display from Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector.

The second highest ETmiss monojet event in the 2016 ATLAS data (Event 738941529 Run 302393) . A jet with pT of 1707 GeV is indicated by the green and yellow bars corresponding to the energy deposition in the electromagnetic and hadronic calorimeters respectively. The ETmiss of 1735 GeV is shown as the white dashed line in the opposite side of the detector. No additional jets with pT above 30 GeV are found.

#### Four-lepton candidate event with two electrons and two muons recorded in 2016 - ATLAS-CONF-2017-053

A visualization of the only event observed (Event 2667756788, Run 304128) in the four-lepton signal region. The event contains four leptons: two electrons and two muons with a positive and a negative charged lepton in each flavor. The two positively charged tracks are shown in red and the two negatively charged tracks in green. The positive and negative electrons have a pT of 190 GeV and 74 GeV and point in an eta of 1.56 and 0.99 respectively. The positive and negative muons have a pT of 57 GeV and 130 GeV and point in an eta of 1.88 and 2.35 respectively. The same-charge invariant masses are 228 GeV and 207 GeV, while the opposite-charge masses are 163 GeV for the electron pair and 79 GeV for muon pair respectively. The event passes both the analysis Z veto and the mass difference selections.

#### Event with the highest mT in the electron channel recorded in 2016 - arXiv:1706.04786

Display of the event with the highest mT in the electron channel found in the √s = 13 TeV data. The event contains an electron with pT = 1.10 TeV, η = 1.2, φ = 0.9. The missing transverse energy is ETmiss = 1.16 TeV and φ = -2.3. The transverse mass is 2.26 TeV. The white dashed line indicates the ETmiss direction. The green and yellow boxes display projections of the electromagnetic and hadronic calorimeter energy depositions and the orange lines represent charged particles with pT > 2 GeV in the inner detector. The view of the event in the plane transverse to the beam direction is shown on the right side in which the high-pT electron is represented by the green boxes in the direction opposite to the ETmiss vector.

### Supersymmetry (Full Run2 event displays page from the SUSY group).

#### Top-antitop b-tag event with five large-R and MJΣ = 0.62 TeV recorded in 2016 - ATLAS-CONF-2016-057

Event display showing a tt b-tag event with 5 large-R jet and MJΣ = 0.62 TeV.

#### Event with large HTincl, large missing transverse momentum, and two muons, recorded in 2016 - arXiv:1611.05791

Event 2680683396 from run 301973, which falls in SRZ, an event with large HTincl, large missing transverse momentum, and two muons that have an invariant mass of 86.2 GeV.

#### Event with large HT, large missing transverse momentum and two muons, recorded in 2016 - arXiv:1611.05791

Event 1590704785 from run 303892, which falls in SR-high, an event with large HT, large missing transverse momentum, and two muons that have an invariant mass of 57.6 GeV.

### Heavy ions

#### Εxclusive γγ→ γγ candidate recorded in 2015 - arXiv:1702.01625 (ATLAS-CONF-2016-111)

Event display for exclusive γγ→ γγ candidate. Event 461251458 from run 287931 recorded on 2015.12.13 at 09:51:07 is shown. Two back-to-back photons (ETγ1 = 12 GeV and ETγ2 = 11 GeV) with an invariant mass of 24 GeV with no additional activity in the detector are presented. All calorimeter cells with E>500 MeV are shown.

## Event displays which are not included in publications or conference notes

### Higgs

#### H->2e2μ candidate event recorded in 2017 (run=327636, event=1535020856).

Display of a candidate Higgs boson event (run=327636, event=1535020856) from proton-proton collisions recorded by ATLAS in 2017 with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the 2e2μ final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the violet cone is a jet. As shown in the lego plot on the right, the electrons have a transverse momentum of 46 and 33 GeV, the muons 25 and 8 GeV and the jet 37 GeV. (Note that the 25 GeV muon is behind the 46 GeV electron in the lego plot.) The invariant mass of the four lepton system is 125 GeV, the dielectron invariant mass is 91 GeV, the dimuon invariant mass is 31 GeV. The calorimeter energy deposits shown are required to be above 1 GeV.

#### H->2e2μ candidate event recorded in 2017 (run=328263, event=953423990).

Display of a candidate Higgs boson event (run=328263, event=953423990) from proton-proton collisions recorded by ATLAS in 2017 with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the 2e2μ final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter. As shown in the lego plot on the right, the electrons have a transverse momentum of 34 and 27 GeV, the muons 24 and 9 GeV. The invariant mass of the four lepton system is 124 GeV, the dielectron invariant mass is 80 GeV, the dimuon invariant mass is 34 GeV. The calorimeter energy deposits shown are required to be above 1 GeV.

#### H->2e2μ candidate event with 25 additional reconstructed primary vertices recorded in 2016.

A display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Higgs boson candidate is reconstructed in a beam crossing with 25 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ2e final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the yellow tracks are the remaining charged particles from the Higgs boson candidate vertex. No jet has been reconstructed with transverse momentum above 30 GeV. The grey tracks correspond to the charged particles from the 25 pileup vertices with transverse momentum above 0.5 GeV and the colored squares in the lower display correspond to the position of the reconstructed vertices. As shown in the lego plot on the right, the muons have a transverse momentum of 29 and 31 GeV, and the electrons 23 and 19 GeV . The invariant mass of the four lepton system is 119 GeV, the dimuon invariant mass is 69 GeV, the dielectron invariant mass is 42 GeV. This event falls within the standard mass selection window of 118 to 129 GeV and has a BDT discriminant response which gives a high probability that this event comes from a Higgs decay as opposed to a background ZZ* decay.

#### H->2e2μ candidate event with 25 additional reconstructed primary vertices recorded in 2016.

A display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Higgs boson candidate is reconstructed in a beam crossing with 25 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ2e final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the yellow tracks are the remaining charged particles from the Higgs boson candidate vertex. No jet has been reconstructed with transverse momentum above 30 GeV. The grey tracks correspond to the charged particles from the 25 pileup vertices with transverse momentum above 1 GeV and the colored squares in the lower display correspond to the position of the reconstructed vertices. As shown in the lego plot on the right, the muons have a transverse momentum of 29 and 31 GeV, and the electrons 23 and 19 GeV . The invariant mass of the four lepton system is 119 GeV, the dimuon invariant mass is 69 GeV, the dielectron invariant mass is 42 GeV. This event falls within the standard mass selection window of 118 to 129 GeV and has a BDT discriminant response which gives a high probability that this event comes from a Higgs decay as opposed to a background ZZ* decay.

#### H->2e2μ candidate event with 25 additional reconstructed primary vertices recorded in 2016.

A display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Higgs boson candidate is reconstructed in a beam crossing with 25 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ2e final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the yellow tracks are the remaining charged particles from the Higgs boson candidate vertex. No jet has been reconstructed with transverse momentum above 30 GeV. The grey tracks correspond to the charged particles from the 25 pileup vertices with transverse momentum above 2 GeV and the colored squares in the lower display correspond to the position of the reconstructed vertices. As shown in the lego plot on the right, the muons have a transverse momentum of 29 and 31 GeV, and the electrons 23 and 19 GeV . The invariant mass of the four lepton system is 119 GeV, the dimuon invariant mass is 69 GeV, the dielectron invariant mass is 42 GeV. This event falls within the standard mass selection window of 118 to 129 GeV and has a BDT discriminant response which gives a high probability that this event comes from a Higgs decay as opposed to a background ZZ* decay.

#### H->2e2μ candidate event with 25 additional reconstructed primary vertices recorded in 2016.

A display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Higgs boson candidate is reconstructed in a beam crossing with 25 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ2e final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the yellow tracks are the remaining charged particles from the Higgs boson candidate vertex. No jet has been reconstructed with transverse momentum above 30 GeV. The grey tracks correspond to the charged particles from the 25 pileup vertices with transverse momentum above 4 GeV and the colored squares in the lower display correspond to the position of the reconstructed vertices. As shown in the lego plot on the right, the muons have a transverse momentum of 29 and 31 GeV, and the electrons 23 and 19 GeV . The invariant mass of the four lepton system is 119 GeV, the dimuon invariant mass is 69 GeV, the dielectron invariant mass is 42 GeV. This event falls within the standard mass selection window of 118 to 129 GeV and has a BDT discriminant response which gives a high probability that this event comes from a Higgs decay as opposed to a background ZZ* decay.

#### H->2e2μ candidate event with 25 additional reconstructed primary vertices recorded in 2016.

A display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Higgs boson candidate is reconstructed in a beam crossing with 25 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ2e final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the yellow tracks are the remaining charged particles from the Higgs boson candidate vertex. No jet has been reconstructed with transverse momentum above 30 GeV. The grey tracks correspond to the charged particles from the 25 pileup vertices with transverse momentum above 8 GeV and the colored squares in the lower display correspond to the position of the reconstructed vertices. As shown in the lego plot on the right, the muons have a transverse momentum of 29 and 31 GeV, and the electrons 23 and 19 GeV . The invariant mass of the four lepton system is 119 GeV, the dimuon invariant mass is 69 GeV, the dielectron invariant mass is 42 GeV. This event falls within the standard mass selection window of 118 to 129 GeV and has a BDT discriminant response which gives a high probability that this event comes from a Higgs decay as opposed to a background ZZ* decay.

#### H->2e2μ candidate event recorded in 2015 (run=280862 event=53564866).

Display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the 2e2μ final state. The right display shows a projection in which only the phi coordinates of the particles and energy deposits are plotted, while the central display shows a 3-dimensional view. The path of the muons is indicated by the red lines, the electrons by the blue lines. The energy deposits in the electromagnetic calorimeter are shown in green, the deposits in the hadronic calorimeter in yellow. In addition to the four leptons, there are two back-to-back jets in the event, as shown by the cones. The electrons have a transverse momentum of 111 and 16 GeV, the muons 18 and 17 GeV, the jets 118 and 54 GeV . The invariant mass of the four lepton system is 129 GeV, the di-electron invariant mass is 91 GeV, the di-muon invariant mass is 29 GeV, the pseudorapidity difference between the two jets is 6.4 while the di-jet invariant mass is 2 TeV.

#### H->2e2μ candidate event recorded in 2015 (run=280862 event=53564866).

Display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the 2e2µ final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the violet cones are two jets. As shown in the lego plot on the right,the electrons have a transverse momentum of 111 and 16 GeV, the muons 18 and 17 GeV, the jets 118 and 54 GeV . The invariant mass of the four lepton system is 129 GeV, the di-electron invariant mass is 91 GeV, the di-muon invariant mass is 29 GeV, the pseudorapidity difference between the two jets is 6.4 while the di-jet invariant mass is 2 TeV.

#### H->2e2μ candidate event recorded in 2015 (run=280464 event=517140616).

Display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the 2µ2e final state. The left display shows a projection in which only the phi coordinates of the particles and energy deposits are plotted, while the central display shows a 3-dimensional view. The path of the muons is indicated by the red lines, the electrons by the blue lines. The energy deposits in the electromagnetic calorimeter are shown in green, the deposits in the hadronic calorimeter in yellow. In addition to the four leptons, there is a jet in the event, as shown by the cone. The muons have a transverse momentum of 55 and 33 GeV, the electrons 14 and 11 GeV and the jet 31 GeV. The invariant mass of the four lepton system is 123 GeV, the di-muon invariant mass is 91 GeV and the di-electron invariant mass is 27 GeV.

#### H->2e2μ candidate event recorded in 2015 (run=280464 event=517140616).

Display of a candidate Higgs boson event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the 2µ2e final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer, the green lines show the paths of the two electrons together with the energy deposit in the electromagnetic calorimeter, and the violet cone is a jet. As shown in the lego plot on the right, the muons have a transverse momentum of 55 and 33 GeV, the electrons 14 and 11 GeV and the jet 31 GeV. The invariant mass of the four lepton system is 123 GeV, the di-muon invariant mass is 91 GeV and the di-electron invariant mass is 27 GeV.

JiveXML_336567_190582407-RZ-EventInfo-2017-12-14-17-26-17.png

### Standard Model

#### Z->μμ candidate event with 17 vertices recorded in 2017.

A display of a Z->μμ candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV on 19th June 2017 (Run 327265, Event 117236869). The Z candidate is reconstructed in a beam crossing with 16 additionally reconstructed vertices from minimum bias interactions. The two muons have p T =31.7 GeV and 28.5 GeV. The invariant mass of the two muons is 91.8 GeV. The left display presents a transverse view of the event (X-Y plane) where the red lines show the two muons' paths. The right display zooms into the interaction region and shows a fraction of the 17 reconstructed vertices. The hard interaction vertex is represented by a red ellipse (on the left of the insert) from which the two muons (red tracks) are emerging. The bottom display presents the event in longitudinal view (Z-Y plane).

#### W-boson produced in association with a top quark in the di-lepton channel candidate event recorded in 2015.

Display of event 1220033035 in run 284285 recorded by ATLAS in proton-proton collisions with LHC stable beams at a centre-of-mass energy of 13 TeV on November 1st, 2015. The topology of this candidate corresponds to the production of a W boson in association with a single top quark in the dilepton channel. Two opposite charged leptons are reconstructed. The reconstructed electron represented by the blue line has a transverse momentum around 32 GeV, being close to the beam pipe. The reconstructed muon, with a transverse momentum around 38 GeV, is represented by the red line. The green and yellow bars indicate energy deposits in the liquid argon and scintillating-tile calorimeters, from these deposits one jet is identified and represented by an azure cone. This central jet, with a transverse momentum around 36 GeV, is identified as having originated from a b-quark. The missing transverse momentum represented by the dotted white line has a magnitude around 57 GeV.

#### W candidate event decaying to one muon and one neutrino, recorded in 2011.

Display of a candidate event for a W boson decaying into one muon and one neutrino from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 7 TeV. The muon (red line) has a transverse momentum of 32.8 GeV and the missing transverse energy is 52.4 GeV (cyan blue line), resulting in a transverse mass of 82.9 GeV of the di-lepton system. Little hadronic activity is measured, indicating a small transverse momentum of the W boson candidate. The event was recorded in June 2011 and was used for the measurement of the W boson mass.

Event details: Run Number 183081, Event Number 101291517, η muon = 0.48, φ muon = -0.08, PTmuon= 32.8 GeV, MT= 82.9 GeV, ETmiss=52.4 GeV.

#### W candidate event decaying to one muon and one neutrino, recorded in 2011.

Display of a candidate event for a W boson decaying into one muon and one neutrino from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 7 TeV. The muon (red line) has a transverse momentum of 32.8 GeV and the missing transverse energy is 52.4 GeV (cyan blue line), resulting in a transverse mass of 82.9 GeV of the di-lepton system. Little hadronic activity is measured, indicating a small transverse momentum of the W boson candidate. The event was recorded in June 2011 and was used for the measurement of the W boson mass.

Event details: Run Number 183081, Event Number 101291517, η muon = 0.48, φ muon = -0.08, PTmuon= 32.8 GeV, MT= 82.9 GeV, ETmiss=52.4 GeV.

#### Dijet event collected in 2017, with mjj=9.3 TeV.

Display of a di-jet event (Run=329716, Event=8575822452) with mjj=9.3 TeV, produced in pp collisions at √s = 13 TeV data in 2017. The two high-pT jets both have pT=2.9 TeV, one is at η=-1.2 (magenta) and the other at η=0.9 (cyan). The view of the event in the plane transverse to the beam direction is shown on the left side. The top-right figure represents the calorimeter clusters transverse energies in the η-φ plane. The bottom-right figure present the event in the longitudinal view (Z-Y plane).

#### Dijet event collected in 2017, with mjj=9.3 TeV.

Display of a di-jet event (Run=329716, Event=8575822452) with mjj=9.3 TeV, produced in pp collisions at √s = 13 TeV data in 2017. The two high-pT jets both have pT=2.9 TeV, one is at η=-1.2 and the other at η=0.9. The two yellow cone represent the reconstructed jets.

### Top

#### Top-antiptop candidate event reconstructed with one electron, one muon and two b-tag jets, recorded in 2016.

Display of a candidate top-antitop event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the electron, muon and 2 b-tag jets final state, which pT are 228 and 154 GeV. The path of the muon is indicated by the red line, the electron by the blue line. The energy deposits in the electromagnetic calorimeter are shown in green, the deposits in the hadronic calorimeter in yellow. The jets are represented by the two yellow cones. The bottom left insert presents a zoom on the proton-proton interaction region. The golden dots represent hits in the four layers of the pixel detector. The inner most layer (the insertable B layer) is at a radius of 3.34 cm from the beam line. The white disks represent primary vertices, and the azure ones vertices compatible with a B-decay.

#### Top-antiptop candidate event reconstructed with one electron, one muon and two b-tag jets, recorded in 2016.

Display of a candidate top-antitop event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The candidate event is reconstructed in the electron, muon and 2 b-tag jets final state, which pT are 228 and 154 GeV. The path of the muon is indicated by the red line, the electron by the blue line. The jets are represented by the two yellow cones. The white disks represent primary vertices, and the azure ones vertices compatible with a B-decay. Primary vertices are represented by a white dot and vertices compatible with the decay of B-meson by an azure dot.

#### Top-antiptop candidate event reconstructed with one electron, one muon and one soft pT muon associated to a b-tag jet, recorded in 2016.

Event display of a ttbar dilepton candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. In addition to two prompt leptons (an electron of 107 GeV and a muon of 268 GeV) a soft muon (7 GeV) is associated to a b-jet candidate (in dR<0.4) tagged by the new BDT-based Soft Muon Tagger algorithm. The light blue lines reaching the Muon Spectrometer (MS) show the path of the two combined muons and the hits in the MS are in red; the electron energy deposit in the electromagnetic calorimeter is showed in green. The red arrow shows the missing transverse energy (181 GeV).

#### Top-antiptop candidate event reconstructed with one electron, one muon and one soft pT muon associated to a b-tag jet, recorded in 2016.

Event display of a ttbar dilepton candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. In addition to two prompt leptons (an electron of 107 GeV and a muon of 268 GeV) a soft muon (7 GeV) is associated to a b-jet candidate (in dR<0.4) tagged by the new BDT-based Soft Muon Tagger algorithm. Zoom on the reconstructed primary vertex (PV, two tracks) and secondary vertex (SV, six tracks) in the Z-rho plane. The track of the muon within the jet tagged by new BDT-based SMT b-tagging algorithm is showed in red. The distance between PV and SV is about 2 mm.

#### Top-antiquark candidate event with a muon, an electron and three jets, recorded in 2015.

Display of a ttbar candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The red line shows the path of a muon with transverse momentum around 140 GeV through the detector. The green line shows the path of an electron with transverse momentum around 170 GeV through the detector. The green and yellow bars indicate energy deposits in the liquid argon and scintillating-tile calorimeters, from these deposits 3 jets are identified with transverse momenta between 30 and 80 GeV. Two of the jets are identified as having originated from b-quarks. Tracks reconstructed from hits in the inner tracking detector are shown as arcs curving in the solenoidal magnetic field. (from the Top group public results page)

A high resolution version is available here.

#### Top-antiquark candidate event with a muon and four jets, recorded in 2015.

Display of a ttbar candidate event from proton-proton collisions recorded by ATLAS on 4 June 2015, with LHC stable beams at a collision energy of 13 TeV. The red line shows the path of a muon with transverse momentum around 35 GeV through the detector. The green and yellow bars indicate energy deposits in the liquid argon and scintillating-tile calorimeters, from these deposits 4 jets are identified with transverse momenta between 25 and 80 GeV. Tracks reconstructed from hits in the inner tracking detector are shown as arcs curving in the solenoidal magnetic field. (from the Top group public results page)

A high resolution version is available here.

#### Candidate event for a t-channel single top-quark production in the muon plus jets channel, recorded in 2015.

Display of event 279124678 in run 267073 recorded by ATLAS in proton-proton collisions with LHC stable beams at a centre-of-mass energy of 13 TeV on June 5th, 2015. The topology of this candidate corresponds to t-channel single top-quark production in the muon plus jets channel. The reconstructed muon represented by the red line has a transverse momentum around 30 GeV through the detector. The green and yellow bars indicate energy deposits in the liquid argon and scintillating-tile calorimeters, from these deposits 2 jets are identified and represented by yellow cones. The central jet, with a transverse momentum around 50 GeV, is identified as having originated from a b-quark. The forward jet, with a transverse momentum around 30 GeV is closer to the beam pipe. The missing transverse momentum represented by the dotted white line has a magnitude around 40 GeV. (from the Top group public results page)

A high resolution version is available here.

#### Boosted top quark pair candidate event recorded in 2015.

Display of a candidate boosted top quark pair production event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The red line shows the path of a muon with transverse momentum around 50 GeV through the detector. The dashed line shows the direction of the missing transverse momentum, which has a magnitude of about 470 GeV. The green and yellow bars indicate energy deposits in the liquid argon and scintillating-tile calorimeters, from these deposits 4 small-radius (R=0.4) jets are identified with transverse momenta between 70 and 300 GeV. Three of these small-radius jets are re-clustered into the leading large-radius (R=1.0) jet (not shown explicitly) with a transverse momentum of about 600 GeV and a jet mass of about 180 GeV, near the top quark mass. One of these three jets in addition to the fourth jet above 70 GeV are identified as having originated from b-quarks. Tracks reconstructed from hits in the inner tracking detector are shown as arcs curving in the solenoidal magnetic field. (from the Top group public results page)

### B Physics and Light States

#### Bs->J/ψφ candidate event recorded in 2017.

Event display of a Bs meson candidate decaying to J/ψφ where the J/ψ meson decays to two oppositely charged muons (illustrated by the red lines) and the φ meson decays to two oppositely charged kaons (illustrated by the blue curves). The event (run=333181, event=1942573294) was recorded by ATLAS with LHC stable beams with proton-proton collisions at a collision energy of 13 TeV on 16th August 2017.

### Exotics

#### Event display of simulated Hidden Sector signal sample at a centre-of-mass energy of 13 TeV

Event display of simulated Hidden Sector (HS) signal sample for the CalRatio displaced jets analysis at a centre-of-mass energy of 13 TeV. This event display shows an HS heavy neutral boson Φ [1000 GeV] decaying to a pair of long-lived particles s [400 GeV], which then each decay to two Standard Model fermions f and fbar. The analysis searches for two long-lived particles decaying in the Hadronic Calorimeter (HCAL) or at the edge of the Electromagnetic calorimeter (ECAL), which results in two jets with no tracks pointing to them and most of the energy deposited in the HCAL, represented by yellow and orange cells, and little energy in the ECAL, which is represented by blue and green cells. The two fermions decaying from each long-lived particle only produce one jet due to their collimation, giving rise to two such jets in the event. Only tracks with transverse momentum over 2 GeV are shown.

#### Search for new heavy particles decaying into dielectron final states, full Run 2 dataset.

Event display of the dielectron candidate with the highest invariant mass in the 2015-18 data taking period with mee = 4.06 TeV. The properties of the leading electron are ET = 2.01 TeV, η = 0.47 and φ = -0.78. The properties of the subleading electron are ET = 1.92 TeV, η = -0.03 and φ = 2.37. The analysis ATLAS-CONF-2019-001 searched for new heavy particles decaying into dilepton final states. This event display is from this analysis but was not included in the CONF note.

#### Search for new heavy particles decaying into dimuon final states, full Run 2 dataset.

Event display of the dimuon candidate with the highest invariant mass in the 2015-18 data taking period with mμμ = 2.75 TeV. The properties of the leading muon are pT = 1.82 TeV, η = -0.52 and φ = -0.56. The properties of the subleading muon are pT = 1.04 TeV, η = -0.67 and φ = 2.53. The jets that are overlapping with the muons have pT < 50 GeV and are thus most probably induced by the calorimeter deposits of the muon. The dimuon mass resolution is about 15% at 2.75 TeV. The analysis ATLAS-CONF-2019-001 searched for new heavy particles decaying into dilepton final states. This event display is from this analysis but was not included in the CONF note.

#### Dijet event collected in 2017, with mjj=9.3 TeV.

Display of a di-jet event (Run=329716, Event=8575822452) with mjj=9.3 TeV, produced in pp collisions at √s = 13 TeV data in 2017. The two high-pT jets both have pT=2.9 TeV, one is at η=-1.2 (magenta) and the other at η=0.9 (cyan). The view of the event in the plane transverse to the beam direction is shown on the left side. The top-right figure represents the calorimeter clusters transverse energies in the η-φ plane. The bottom-right figure present the event in the longitudinal view (Z-Y plane).

### Heavy Ions

#### Event display (run 365914, event 562492194) of a back-to-back electron-muon pair in an ultra-peripheral collision recorded with the ATLAS detector during the 2018 Pb+Pb data-taking period - 14th November 2018.

Event display (run 365914, event 562492194) of a back-to-back electron-muon pair in an ultra-peripheral collision recorded with the ATLAS detector during the 2018 Pb+Pb data-taking period. A total of two tracks are reconstructed, one corresponding to the electron and the other the muon. The electron – shown in green – deposits in the electromagnetic calorimeter. The muon – shown in red – leaves less energy in the calorimeters, but is also observed in the muon spectrometer. The electron is measured to have positive charge and a transverse momentum of 11.9 GeV, and the muon is negatively charged with a transverse momentum of 11.7 GeV. In the transverse plane, the pair has an acoplanarity of 0.0132. All calorimeter cells with a transverse energy above 500 MeV are shown.

#### Event display (run 365681, event 1064766274) of an ultra-peripheral photo-nuclear collision recorded by the ATLAS detector during 2018 Pb+Pb collision period - 11th November 2018.

Event display (run 365681, event 1064766274) of an ultra-peripheral photo-nuclear collision recorded by the ATLAS detector during 2018 Pb+Pb collision period. The event topology includes large rapidity gaps between calorimeter energy deposits as well as asymmetry in the total transverse energy in the forward calorimeters (71 GeV left, 0.9 GeV right). 71 tracks were measured above 400 MeV in transverse momentum, and are colored based on their charge. The total energy in the forward calorimeters is displayed in green.

#### Event display (run 366011, event 999067412) with an unbalanced high-pT photon+jet pair, from Pb-Pb collisions - 15th November 2018

Display of an event (run 366011, event 999067412) containing an unbalanced, high-pT photon+jet pair. The event was recorded with the ATLAS high level trigger during the 2018 Pb+Pb collision period. The event has a total of 3.74 TeV measured in the forward calorimeters, corresponding to a centrality percentile of 4%. The photon has 420 GeV of transverse momentum, passes the tight identification criteria, and is isolated. The jet, with a pT of 289 GeV, does not balance the photon in the transverse plane.

#### Event display (run 365573, event 400666938) with three high-pT jets, from Pb-Pb collisions - 10th November 2018

Event display (run 365512, event 130954442) with three high-pT jet event recorded during the 2018 Pb+Pb run at center-of-mass energy of 5.02 TeV. In this event, the leading 415 GeV jet is azimuthally balanced by the two smaller sub-leading jets (230 and 207 GeV). A total of 0.5 TeV of transverse energy was deposited in the forward calorimeters, corresponding to a centrality percentile of approximately 50%.

#### Display of a candidate event (run 365512, event 130954442) gamma-gamma-> e+e- from Pb-Pb collisions - 9th November 2018

Event display (run 365512, event 130954442) for an exclusive $\gamma\gamma\rightarrow ee$ candidate in ultra-peripheral collision in 2018 Pb+Pb dataset, recorded on 9th of November 2018 at 07:56:44. Two back-to-back electrons (pTe1 = 8.2 GeV and pTe2 = 7.4 GeV) with an invariant mass of 16 GeV are presented. All charged-partice tracks with pT > 100 MeV are shown. All calorimeter cells with various ET thresholds are shown: ET > 250 MeV for EMB, EMEC and Tile, ET > 800 MeV for HEC, and ET > 1000 MeV for FCAL.

#### Display of a photon-jet event (run 365602, event 855982997) from Pb-Pb collisions - 10th November 2018

Display of an event (run 365602, event 855982997) with an azimuthally balanced pair of high-pT photon and jet, taken using the high-level photon trigger during the 2018 Pb+Pb data taking at the centre-of-mass energy of 5.02 TeV. The photon is isolated, passes tight identification criteria, and has pT = 211 GeV. The balancing jet has a pT of 200 GeV, deposited in both the electromagnetic and hadronic calorimeters. A total of 1.37 TeV of transverse energy is deposited in the forward calorimeters, which corresponds approximately to a centrality percentile of 30%.

#### Event display (run 365512, event 110420355) fromPb-Pb collisions (stable beam) - 9th November 2018

Event display (run 365512, event 110420355) from lead-lead collision data recorded with the ATLAS detector on 9 November 2018 with stable beams. Orange, green, and cyan boxes indicate energy deposits in the calorimeter systems. Orange lines indicate the trajectories of charged particles recorded by the inner detector tracking systems.

#### Event display (run 365512, event 110420355) fromPb-Pb collisions (stable beam) - 9th November 2018

Event display (run 365512, event 110420355) from lead-lead collision data recorded with the ATLAS detector on 9th November 2018 with stable beams. Curved colored lines show the trajectories of charged particles in the inner detector tracking systems. Yellow boxes indicate energy deposits in the calorimeter systems. The top right plot shows the distribution of energy deposited in the calorimeters, demonstrating the high particle multiplicity of the event.

#### Event display (run 365276, event 342956912) fromPb-Pb collisions - 6th November 2018

Event display from PbPb collisions recorded in ATLAS on 6 November 2018, during the startup of the 2018 LHC heavy ion program. Colored lines show the trajectories of charged particles in the tracking systems. Yellow boxes indicate energy depositions in the calorimeter systems. The event was recorded during the first 2018 fill with Pb-Pb collisions, when beams were not declared stable; therefore the voltage of the silicium detectors (pixels and SCT) was not at nominal value.

#### Event display (run 338037, event 657472305) from Xenon-Xenon collisions - 12-13 October 2017

Event display (run 338037, event 657472305) from the xenon-xenon collision run of 12-13 October 2017. Curved cyan lines show the trajectories of charged particles in the tracking systems. The bottom right plot shows the distribution of energy deposited in the calorimeters, demonstrating the high particle multiplicity of the event. Two muon candidates are reconstructed at high pseudorapidity, as seen in the bottom left plot.

#### Event display (run 338037, event 808999132) from Xenon-Xenon collisions - 12-13 October 2017

Event display (run 338037, event 808999132) from the xenon-xenon collision run of 12-13 October 2017. Curved white lines show the trajectories of charged particles in the tracking systems. The bottom right plot shows the distribution of energy deposited in the calorimeters, demonstrating the high particle multiplicity of the event.

### High-pileup displays

#### Event Display of a simulated Ζ->μμ event with three different pile-up conditions (μ=2,50,140).

A simulated Ζ->μμ event at a centre-of-mass energy of 13 TeV overlaid with pile-up conditions expected at μ=2 average collisions per bunch crossing. The Run-2 simulation and reconstruction were used. Tracks with pT > 500 MeV are displayed. The muon tracks are coloured in red.

#### Event Display of a simulated Ζ->μμ event with three different pile-up conditions (μ=2,50,140).

A simulated Ζ->μμ event at a centre-of-mass energy of 13 TeV overlaid with pile-up conditions expected at μ=50 average collisions per bunch crossing. The Run-2 simulation and reconstruction were used. Tracks with pT > 500 MeV are displayed. The muon tracks are coloured in red.

#### Event Display of a simulated Ζ->μμ event with three different pile-up conditions (μ=2,50,140).

A simulated Ζ->μμ event at a centre-of-mass energy of 13 TeV overlaid with pile-up conditions expected at μ=140 average collisions per bunch crossing. The Run-2 simulation and reconstruction were used. Tracks with pT > 500 MeV are displayed. The muon tracks are coloured in red.

#### Event Display of a simulated Ζ->μμ event with three different pile-up conditions (μ=2,50,140).

A simulated Ζ->μμ event at a centre-of-mass energy of 13 TeV overlaid with pile-up conditions expected at μ=2, 50, 140 average collisions per bunch crossing. The Run-2 simulation and reconstruction were used. Tracks with pT > 500 MeV are displayed. The muon tracks are coloured in red. Animation that cycles tthrough all three pile-up scenarios.

#### Ζ->μμ candidate event with 65 additional reconstructed primary vertices recorded in 2017.

A display of a Z->μμ candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV on the 29th of September 2017 (Run 336852, Event 883966264). The Z boson candidate is reconstructed in a beam crossing with 65 additionally reconstructed vertices from minimum bias interactions. The two muons have PTμ =61.5 GeV and 60 GeV. The invariant mass of the two muons is 87 GeV. Calorimeter cells with ET > 500 MeV are shown. The upper left display presents a transverse view of the event (X-Y plane) where the yellow lines show the two muons' paths. The upper right display shows the 66 reconstructed vertices. The bottom display presents the event in longitudinal view (Z-Y plane). Tracks with PT >100 MeV are displayed.

#### Ζ->μμ candidate event with 65 additional reconstructed primary vertices recorded in 2017.

A display of a Z->μμ candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV on the 29th of September 2017 (Run 336852, Event 883966264). The Z boson candidate is reconstructed in a beam crossing with 65 additionally reconstructed vertices from minimum bias interactions. The two muons have PTμ =61.5 GeV and 60 GeV. The invariant mass of the two muons is 87 GeV. Tracks with PT >100 MeV are displayed.

#### Ζ->μμ candidate event with 65 additional reconstructed primary vertices recorded in 2017.

A display of a Z->μμ candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV on the 29th of September 2017 (Run 336852, Event 883966264). The Z boson candidate is reconstructed in a beam crossing with 65 additionally reconstructed vertices from minimum bias interactions. The two muons have PTμ =61.5 GeV and 60 GeV. The invariant mass of the two muons is 87 GeV. The three panels, from top to bottom, show tracks with a cut on track PT of 100 MeV, 1 GeV and 5 GeV respectively.

#### Ζ->μμ candidate event with 28 additional reconstructed primary vertices recorded in 2018.

A display of a candidate Ζ boson event (run 349114, event number 216445472) from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Ζ boson candidate is reconstructed in a beam crossing with 28 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ final state. In the left display, the red lines show the path of the two muons including the hits in the muon spectrometer and the yellow tracks are the remaining charged particles from the 29 vertices, with transverse momentum above 0.5 GeV. The colored squares in the lower display correspond to the position of the reconstructed vertices. The invariant mass of the two muons is 92.3 GeV.

#### Ζ->μμ candidate event with 28 additional reconstructed primary vertices recorded in 2018.

A display of a candidate Ζ boson event (run 349114, event number 216445472) from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV. The Ζ boson candidate is reconstructed in a beam crossing with 28 additionally reconstructed primary vertices from the minimum bias interactions. The candidate event is reconstructed in the 2µ final state. This display is a zoom of the inner detector; the red lines show the path of the two muons including the hits in the muon spectrometer and the yellow tracks are the remaining charged particles from the 29 vertices, with transverse momentum above 0.5 GeV. The white circles in the center of the display correspond to the position of the reconstructed vertices. The invariant mass of the two muons is 92.3 GeV.

#### Z->μμ candidate event with 25 vertices recorded in 2017.

A display of a Z->μμ candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV on 25th September 2017 (Run 336567, Event 190582407). The Z candidate is reconstructed in a beam crossing with 24 additionally reconstructed vertices from minimum bias interactions. The two muons have PTμ=46.5 GeV and 34.3 GeV. The invariant mass of the two muons is 91.1 GeV. The left display presents a transverse view of the event (X-Y plane) where the red lines show the two muons' paths. The right display zooms into the interaction region and shows a fraction of the 25 reconstructed vertices. The hard interaction vertex is represented by a green square from which the two muons (red tracks) are emerging. The bottom display presents the event in longitudinal view (Z-Y plane). Tracks with pT > 500 MeV are displayed.

#### Z->μμ candidate event with 25 vertices recorded in 2017.

A display of a Z->μμ candidate event from proton-proton collisions recorded by ATLAS with LHC stable beams at a collision energy of 13 TeV on 25th September 2017 (Run 336567, Event 190582407). The Z candidate is reconstructed in a beam crossing with 24 additionally reconstructed vertices from minimum bias interactions. The two muons have PTμ=46.5 GeV and 34.3 GeV. The invariant mass of the two muons is 91.1 GeV. The display is a zoom into the interaction region and shows a fraction of the 25 reconstructed vertices. The hard interaction vertex is represented by a green square from which the two muons (red tracks) are emerging. Tracks with pT > 500 MeV are displayed.

#### Two Z->μμ candidate events associated to two vertices recorded in 2017.

ATLAS 2017 collision data event with two Z-boson candidates each decaying to two muons and originating from well separated pp interactions in the same LHC bunch crossing. The Z candidates have invariant mass of 91 GeV and 81 GeV, respectively, with muon transverse momenta of 40.7, 31.4 GeV and 45.6, 38.7 GeV. The production vertices of the two Z boson candidates are separated by 67 mm.

#### Two Z->μμ candidate events associated to two vertices recorded in 2017.

ATLAS 2017 collision data event with two Z-boson candidates each decaying to two muons and originating from well separated pp interactions in the same LHC bunch crossing. The Z candidates have invariant mass of 91 GeV and 81 GeV, respectively, with muon transverse momenta of 40.7, 31.4 GeV and 45.6, 38.7 GeV. The production vertices of the two Z boson candidates are separated by 67 mm.

### Beam commissioning and first collisions event displays

#### Beam splash event recorded on 6th April 2018.

The image shows a visualization of experimental data coming from the 'beam splash' tests run in April 2018 as part of the restart process of the LHC accelerator, after the winter break for maintenance. The image shows the hits of part of the tracking detector (in red, at the center), the energy deposits in the electromagnetic calorimeter (in green), and those in the hadronic calorimeter (in yellow). The semi-transparent azure volumes are part of the hadronic calorimeter, while the grey outer structure is part of the muon spectrometer.

#### ATLAS collision event from the first LHC fill with stable beam on 17th April 2018.

Event display (run 348197, event 562578) from the first stable beam proton-proton collision run of 2018, recorded on April 17. Curved white lines show the trajectories of charged particles in the tracking systems.

#### ATLAS collision event from the first LHC fill with stable beam on 17th April 2018.

Event display (run 348197, event 921894) from the first stable beam proton-proton collision run of 2018, recorded on April 17. Orange lines show the trajectories of charged particles in the tracking systems. The green and yellow boxes show the energy deposits in the electromagnetic and hadronic calorimeters, respectively. The three yellow cones show jets of particles produced in the collision.

Responsible: Manuella Vincter
Subject: public

Topic attachments
I Attachment History Action Size Date Who Comment
png ATLAS_VP1_event_display_Bs_toJPsi_phi.png r1 manage 2215.9 K 2019-04-02 - 11:37 ManuellaVincter
png ATLAS_calRatio_eventDisplay.png r1 manage 2008.5 K 2019-08-09 - 17:59 ManuellaVincter
gif ATLAS_highMultiplicityZmumu_2_50_140.gif r1 manage 10613.1 K 2019-08-02 - 15:32 ManuellaVincter Simulated Zmumu Run 2 for mu=2,50,140
png ATLAS_highMultiplicityZmumu_VP1EventDisplays_mu140.png r1 manage 4448.5 K 2019-08-02 - 15:32 ManuellaVincter Simulated Zmumu Run 2 for mu=2,50,140
png ATLAS_highMultiplicityZmumu_VP1EventDisplays_mu2.png r1 manage 2419.8 K 2019-08-02 - 15:32 ManuellaVincter Simulated Zmumu Run 2 for mu=2,50,140
png ATLAS_highMultiplicityZmumu_VP1EventDisplays_mu50.png r1 manage 3540.0 K 2019-08-02 - 15:32 ManuellaVincter Simulated Zmumu Run 2 for mu=2,50,140
jpg figaux_01_dm.jpg r1 manage 333.7 K 2018-11-20 - 08:56 CarlGwilliam
Topic revision: r69 - 2019-08-09 - ManuellaVincter

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