# Combined Muon Performance Public Results

## Muon Journal Papers

Full Title Journal Links Status Groups
PUBLISHED  Standalone Vertex Finding in the ATLAS Muon Spectrometer JINST Inspire, arXiv JINST 9 (2014) P02001
(Submitted: 2013/11/28)
MUON / EXOT
PUBLISHED  Muon reconstruction and identification efficiency in ATLAS using the full Run 2 $pp$ collision data set at $\sqrt{s}=13$ TeV EPJC Inspire, arXiv, Figures Eur. Phys. J. C 81 (2021) 578
(Submitted: 2020/12/01)
MUON
PUBLISHED  Muon reconstruction performance of the ATLAS detector in proton--proton collision data at $\sqrt{s}$=13 TeV EPJC Inspire, arXiv, Figures Eur. Phys. J. C 76 (2016) 292
(Submitted: 2016/03/17)
MUON
PUBLISHED  Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data EPJC Inspire, arXiv, Figures Eur. Phys. J. C 74 (2014) 3130
(Submitted: 2014/07/15)
MUON
PUBLISHED  Muon Reconstruction Efficiency and Momentum Resolution of the ATLAS Experiment in Proton-Proton Collisions at $\sqrt{s}$= 7 TeV in 2010 EPJC Inspire, arXiv, Figures Eur. Phys. J. C 74 (2014) 3034
(Submitted: 2014/04/17)
MUON
PUBLISHED  Commissioning of the ATLAS Muon Spectrometer with Cosmic Rays EPJC Inspire, arXiv, Figures Eur. Phys. J. C 70 (2010) 875
(Submitted: 2010/06/22)
MUON
|

## Muon Conference Notes

Full Title Ref Code Publication Date Groups
Muon reconstruction and identification efficiency in ATLAS using the full Run 2 $pp$ collision data set at $√s=13$ TeV ATLAS-CONF-2020-030 2020/07/30 MUON
Preliminary muon reconstruction efficiency and momentum resolution with the ATLAS detector during 2012 pp collisions. ATLAS-CONF-2013-088 2013/08/15 MUON
Reconstruction of collinear Q√ED final state radiation photons in Z → μμ decays produced in s = 7 TeV proton-proton collisions ATLAS-CONF-2012-143 2012/11/06 MUON
A measurement of the muon reconstruction efficiency in 2010 ATLAS data using jψ decays ATLAS-CONF-2012-125 2012/08/27 MUON
Muon reconstruction efficiency in reprocessed 2010 LHC proton-proton collision data recorded with the ATLAS detector ATLAS-CONF-2011-063 2011/04/18 MUON
ATLAS Muon Momentum Resolution in the First Pass Reconstruction of the 2010 p-p Collision Data at √s=7 TeV ATLAS-CONF-2011-046 2011/03/22 MUON
A measurement of the ATLAS muon reconstruction and trigger efficiency using J/ψ decays in p-p collisions at √s=7 TeV ATLAS-CONF-2011-021 2011/03/12 MUON
Determination of the muon reconstruction efficiency in ATLAS at the Z resonance in proton-proton collisions at √s=7 TeV ATLAS-CONF-2011-008 2011/02/16 MUON
Di-muon composition in ATLAS at 7 TeV ATLAS-CONF-2011-003 2011/02/07 MUON
Extraction of the prompt muon component in inclusive muons produced at sqrts = 7 TeV ATLAS-CONF-2010-075 2010/07/21 MUON
Muon Reconstruction Performance ATLAS-CONF-2010-064 2010/07/23 MUON
Observation of W→lnu and Z→ll production in proton-proton collisions at √s = 7 TeV with the ATLAS detector ATLAS-CONF-2010-044 2010/06/03 STDM / EGAM / JETM / MUON
Muon Performance in Minimum Bias pp Collision Data at √=7 TeV with ATLAS ATLAS-CONF-2010-036 2010/06/07 MUON
Preliminary studies for the measurement of the inclusive muon spectrum in pp collisions at √s=7 TeV with the ATLAS detector ATLAS-CONF-2010-035 2010/06/06 MUON
Identification of muon candidates in pp collisions at √s=900 GeV with the ATLAS Detector ATLAS-CONF-2010-015 2010/03/26 MUON
Number of ConfNotes: 15

(The above is included from the auto generated Twiki CombinedMuonCONFnotes)

## Preliminary Figures from 2011 Collision Data at 7 TeV

#### Di-muon invariant mass resolution in Z->µµ decays at 7 TeV

Invariant mass resolution for combined muons with 205 pb-1
• Di-muon invariant mass distribution for oppositely charged muon pairs with transverse momentum above 20 GeV and calorimeter isolation (sum of calorimeter cell energies <2 GeV in a cone of ΔR=0.3.).
• Both muons are restricted to |eta|<2.5.
• Collision events are selected from event filter triggers of 20 GeV threshold.
• The momentum vector is jointly reconstructed in the muon spectrometer and the inner tracking detector (“combined muon”).
• The measured di-muon mass is compared to Monte Carlo prediction using Pythia generated Z->µµ events.

eps file

 Dimuon mass resolution of combined muons in different pseudorapidity regions. The experimental resolution is compared to Monte Carl predictions using Pythia generated Z->μ&mu events. eps file Dimuon mass resolution of the inner detector in different pseudorapidity regions. The experimental resolution is compared to Monte Carl predictions using Pythia generated Z->μ&mu events. The differences between the experimental and predicted resolutions are caused by the residual misalignment of the inner detector. eps file Dimuon mass resolution of the muon spectrometer in different pseudorapidity regions. The experimental resolution is compared to Monte Carl predictions using Pythia generated Z->μ&mu events. The differences between the experimental and predicted resolutions are caused by missing inert material in the Monte-Carlo simulation. eps file

#### Muon reconstruction efficiencies dertermined Z->μμ decays at 7 TeV

Inner detector muon efficiency
Measured inner detector muon reconstruction efficiency for two sets of hit requirements for muons with pT>20 GeV as a function of the muon's pseudorapidity.

eps file

 Inner detector muon efficiency applying ID hit requirements Measured inner detector muon reconstruction efficiency for two sets of hit requirements for muons with pT>20 GeV as a function of the muon's pseudorapidity. The efficiency dips at η~0 and |η|~1.2 are caused by hit requirements imposed on the reconstructed muon. eps file Combined muon efficiency for chain 1 Combined muon reconstruction efficiency with respect to the inner tracking efficiency as a function of the pseudorapidity of the muon for muons with pT > 20 GeV. The panel at the bottom shows the ratio between the measured and predicted efficiencies. eps file Combined muon efficiency for chain 2 Combined muon reconstruction efficiency with respect to the inner tracking efficiency as a function of the pseudorapidity of the muon for muons with pT > 20 GeV. The panel at the bottom shows the ratio between the measured and predicted efficiencies. eps file Combined plus segment tagged muon efficiency for chain 1 Combined muon reconstruction efficiency with respect to the inner tracking efficiency as a function of the pseudorapidity of the muon for muons with pT > 20 GeV. The panel at the bottom shows the ratio between the measured and predicted efficiencies. eps file Combined plus segment tagged muon efficiency for chain 2 Combined muon reconstruction efficiency with respect to the inner tracking efficiency as a function of the pseudorapidity of the muon for muons with pT > 20 GeV. The panel at the bottom shows the ratio between the measured and predicted efficiencies. eps file

## Preliminary Figures from 2010 Collision Data at 7 TeV

#### Di-muon invariant mass resolution in Z->µµ decays at 7 TeV

 Invariant mass resolution for combined muons with 42pb-1 Di-muon invariant mass distribution for oppositely charged muon pairs with transverse momentum above 20 GeV and a track isolation (sum of the transverse momenta of the tracks in a cone of (∆Phi)2+(∆eta)2<(0.4)2 around the muon is less than 20% of the muon's). Both muons are restricted to |eta|<1.05. Collision events are selected from event filter triggers of 10, and with higher luminosity 13 GeV threshold. The momentum vector is jointly reconstructed in the muon spectrometer and the inner tracking detector (“combined muon”). The measured di-muon mass is compared to Monte Carlo prediction using Pythia-generated Z->µµ events. eps file
 Invariant mass resolution for muons measured with the Inner Detector Di-muon invariant mass distribution for oppositely charged muon pairs with transverse momentum above 20 GeV and a track isolation (sum of the transverse momenta of the tracks in a cone of (∆Phi)2+(∆eta)2<(0.4)2 around the muon is less than 20% of the muon's). Both muons are restricted to |eta|<1.05. Collision events are selected from event filter triggers of 10, and with higher luminosity 13 GeV threshold. The momentum vector is reconstructed by the inner tracking detector after it was identified as combined muon. The measured di-muon mass is compared to Monte Carlo prediction using Pythia-generated Z->µµ events. eps file
 Invariant mass resolution for muons measured only with the Muon Spectrometer Di-muon invariant mass distribution for oppositely charged muon pairs with transverse momentum above 20 GeV and a track isolation (sum of the transverse momenta of the tracks in a cone of (∆Phi)2+(∆eta)2<(0.4)2 around the muon is less than 20% of the muon's). Both muons are restricted to |eta|<1.05. Collision events are selected from event filter triggers of 10, and with higher luminosity 13 GeV threshold. The momentum vector is reconstructed by the muon spectrometer and extrapolated to the collision primary vertex after it was identified as combined muon. The measured di-muon mass is compared to Monte Carlo prediction using Pythia-generated Z->µµ events. eps file
 Improvement to the invariant mass resolution with the November data reprocessing Di-muon invariant mass distribution for oppositely charged muon pairs with transverse momentum above 20 GeV and the above track isolation. The momentum vector is jointly reconstructed in the muon spectrometer and the inner tracking detector. The measured di-muon mass is shown for the full pp data of 2010 in first-pass reconstruction using preliminary calibration and alignment constants and after the reprocessing of the data with improved calibration and alignment constants. The distribution is compared to MC prediction using Pythia-generated Z->µµ events and reconstructed with the same software version as the original data processing. eps file
 Improvement to the invariant mass resolution with the November data reprocessing Dimuon event selection like above. The muon momenta are measured by the inner detector only. eps file
 Improvement to the invariant mass resolution with the November data reprocessing Dimuon event selection like above. The muon momenta are measured by the muon spectrometer only and corrected for the energy loss of the muons in the calorimeter. eps file

#### Di-muon invariant mass distribution for 40.0pb-1 at 7 TeV

 Di-muon invariant mass spectrum Di-muon invariant mass spectrum for data, from fully combined opposite sign muons in EF_MU15 triggered events. The muon Event Filter trigger applies a pT threshold at ~15GeV, which for consistency is reconfirmed offline for one of the two inner detector-muon spectrometer combined tracks (the other one is required to pass a p_T threshold of 2.5 GeV). The plot shown corresponds to an integrated luminosity of about 40 pb−1. Differences to the previous plots arise mainly from the use of a high trigger threshold and from plotting the event density in each bin. eps file

#### Di-muon invariant mass distribution for 3.0pb-1 at 7 TeV

 Di-muon invariant mass spectrum Di-muon invariant mass spectrum for data, from fully combined opposite sign muons in L1_MU6 triggered events. The muon trigger applies a p_T threshold at ~6GeV, while the two inner detector-muon spectrometer combined tracks have a p_T threshold of 4 and 2.5 GeV respectively. The plot shown corresponds to an integrated luminosity of about 3.0 pb−1. eps file

#### Di-muon invariant mass distribution for 330nb-1 at 7 TeV

 Di-muon invariant mass spectrum Di-muon invariant mass spectrum for data, from fully combined opposite sign muons in L1_MU6 triggered events. The muon trigger applies a p_T threshold at ~6GeV, while the inner detector-muon spectrometer combined tracks have an effective p_T threshold of ~4GeV in the barrel, which decreases at high pseudo-rapidity. No explicit selection on muon p_T is applied. The plot shown corresponds to an integrated luminosity of 330 nb−1. Plot prepared for and presented at ICHEP 2010. Kept for reference. For more recent talks please use the 3.0 pb−1 distribution. eps file

#### Di-muon invariant mass distribution for 320µb-1 at 7 TeV

Di-muon invariant mass distribution for 320µb-1 at 7 TeV using minimum bias trigger
• Di-muon invariant mass distribution for oppositely charged muon pairs with an energy above 3 GeV each: calculated from inner detector track parameters after fit to a common vertex.
• At least one muon must be jointly reconstructed in the muon spectrometer and the inner tracking detector (“combined muon”).
• The fit to the distribution is an unbinned maximum likelihood fit, using event-by-event errors calculated for each di-muon:
Gaussian-mean mass: 3.06±0.02 GeV
Resolution: 0.08±0.02 GeV
Number of signal events: 49±12
Number of background events: 28±4
• The mass region shown in the plot is fitted. Signal and background are computed in a mass range: 2.82-3.30GeV (3 σ around the peak).

eps file

## Preliminary Figures from 2009 Collision Data at 900 GeV

### Figures for runs 142171, 142174, 142189, 142191, 142193, 142195, 142383 (TOROID ON)

 The Solenoid field was on. The Toroid field was raised to nominal value during run 142171. As a consequence only the last Luminosity Blocks of that run are considered here. The Luminosity Blocks used were obtained requesting safe beams from LHC and all the relevant detectors (MDTs, RPCs, TGCs, Pixels, SCT, TRT) to be operated at nominal HV. Also the level 1 central trigger processor and DAQ status were checked to be good. Collisions were selected considering only paired Bunch Crossing Identifiers and through the timing of MBTS or LAr Only events with at least 3 tracks in Inner Detector, with at least 1 Pixel hits and 6 SCT hits, and with one track with p > 4 GeV, were considered Tight cuts on the muon candidates were applied requesting a confirmation in the Inner Detector for all of them Results shown here are for the muon candidates with p > 4 GeV, pt > 2.5 GeV and abs(eta)<2.5 (50 candidates) and are compared to the non-diffractive Minimum bias MC normalized to the number of entries

#### Parameter distributions in Data and Simulation

Azimuthal angle distribution for muon candidates
The anglular track parameter is measured by the Inner Detector.
The distribution is flat in Φ, as expected for collisions.

eps file

Pseudorapidity distribution for muon candidates
The pseudorapidity is measured by the Inner Detector.
Distribution peaked at large η, as expected for minimum bias p-p collisions

eps file

transverse momentum distribution for muon candidates
The transverse momentum is measured by the Inner Detector.

eps file

momentum distribution for muon candidates
The momentum is measured by the Inner Detector.

eps file

### Figures for runs 141749 and 141811 (TOROID OFF)

The toroid magnets, which bend the muon tracks in the z projection, were OFF for runs 141749 and 141811, so the muons follow a straight path and the momentum is not measured in the spectrometer.
However, the acceptance is increased due to the fact that even very low momentum muons can traverse the spectrometer.
Cathode Strip Chambers are not yet included in the runs 141749 and 141811
*Event Selection and Data Sets*
cut description
Numbers of events passing
runs 141749 and 14181
Coincidence in MBTS (Min-bias trigger) and LAr timing 8k + 20k
Good luminosity block and BCID per run
Run 141749: LB 23-102
BCID:1, 899, 2674
Run 141811: LB 126-165
activity in the muon spectrometer
2022
ID Selection criteria
P(ID) > 3 GeV
at least 3 ID tracks with N(Pixel+SCT)>5
124
Combined and Standalone tracks with trigger chamber hits (RPC, TGC) 83

#### Event Display

Run 141749 event 133538
Event display of a collision with two muon candidates in the end-cap. A full track fit has been successfully applied to the combined Atlas.InnerDetector - Atlas.MuonSpectrometer trajectory of both candidates.

#### Track parameter distributions

Azimuthal angle distribution for muon candidates
The distribution is flat in Φ, as expected for collisions.

eps file

Pseudorapidity distribution for muon candidates
Distribution peaked at large η, as expected for minimum bias p-p collisions

eps file

Impact parameters distribution for muon candidates
The impact parameter of a track is defined as the (geometrically signed) closest distance in the plane transverse to the beam line. The expected width due to multiple scattering of 3 GeV momentum muons is about 200 mm - consistent with the measured value.

eps file

Last reviewed by: Never reviewed

Topic attachments
I Attachment History Action Size Date Who Comment
pdf ATL-COM-MUON-2011-033.pdf r1 manage 2038.4 K 2012-01-19 - 11:26 StefaniaSpagnolo Approved plots: muon rec. efficiency at low pT with J/Psi in 2010 full stat.
pdf ATL-COM-PHYS-2011-1503.pdf r1 manage 1872.9 K 2011-11-17 - 11:44 OliverKortner
pdf ATL-COM-PHYS-2011-1504.pdf r1 manage 1752.1 K 2011-11-17 - 11:50 OliverKortner
png Dimuon_mass.png r1 manage 16.8 K 2010-07-23 - 20:38 DomiziaOrestano
eps Dimuon_mass_896.eps r1 manage 50.8 K 2010-08-24 - 12:53 DomiziaOrestano
png Dimuon_mass_896.png r1 manage 16.9 K 2010-08-24 - 12:53 DomiziaOrestano
eps MUID_combined_id_vs_eta.eps r1 manage 61.9 K 2011-05-31 - 09:07 OliverKortner
png MUID_combined_id_vs_eta.png r1 manage 130.5 K 2011-05-31 - 09:08 OliverKortner
eps MUID_tight_id_vs_eta.eps r1 manage 61.9 K 2011-05-31 - 09:08 OliverKortner
png MUID_tight_id_vs_eta.png r1 manage 126.1 K 2011-05-31 - 09:09 OliverKortner
eps STACO_combined_id_vs_eta.eps r1 manage 61.8 K 2011-05-31 - 09:07 OliverKortner
png STACO_combined_id_vs_eta.png r1 manage 135.1 K 2011-05-31 - 09:07 OliverKortner
eps STACO_loose_id_vs_eta.eps r1 manage 61.6 K 2011-05-31 - 09:08 OliverKortner
png STACO_loose_id_vs_eta.png r1 manage 127.8 K 2011-05-31 - 09:08 OliverKortner
eps effiID_MCP_vs_eta.eps r1 manage 23.9 K 2011-05-31 - 09:06 OliverKortner
png effiID_MCP_vs_eta.png r1 manage 111.4 K 2011-05-31 - 09:07 OliverKortner
eps effiID_MinBias_vs_eta.eps r1 manage 23.9 K 2011-05-31 - 09:06 OliverKortner
png effiID_MinBias_vs_eta.png r1 manage 108.8 K 2011-05-31 - 09:06 OliverKortner
eps etaMuonsPPt.eps r2 r1 manage 10.6 K 2010-03-23 - 16:17 DomiziaOrestano
gif etaMuonsPPt.gif r2 r1 manage 12.6 K 2010-03-23 - 16:18 DomiziaOrestano
eps m12_cb.eps r1 manage 12.4 K 2011-05-31 - 08:10 OliverKortner
png m12_cb.png r1 manage 55.1 K 2011-05-31 - 08:11 OliverKortner
eps momentumMuonsPPt.eps r2 r1 manage 10.3 K 2010-03-23 - 16:19 DomiziaOrestano
gif momentumMuonsPPt.gif r2 r1 manage 12.9 K 2010-03-23 - 16:20 DomiziaOrestano
eps plot_Z_M_CB.eps r1 manage 21.1 K 2011-01-18 - 16:37 OliverKortner
png plot_Z_M_CB.png r1 manage 23.3 K 2011-01-18 - 16:37 OliverKortner
eps plot_Z_M_ID.eps r1 manage 20.7 K 2011-01-18 - 16:47 OliverKortner
png plot_Z_M_ID.png r1 manage 22.3 K 2011-01-18 - 16:47 OliverKortner
eps plot_Z_M_MX.eps r1 manage 20.6 K 2011-01-18 - 16:48 OliverKortner
png plot_Z_M_MX.png r1 manage 22.7 K 2011-01-18 - 16:49 OliverKortner
eps ptMuonsPPt.eps r2 r1 manage 10.0 K 2010-03-23 - 16:20 DomiziaOrestano
gif ptMuonsPPt.gif r2 r1 manage 12.0 K 2010-03-23 - 16:21 DomiziaOrestano
eps res_ID_vs_eta.eps r1 manage 48.9 K 2011-05-31 - 08:12 OliverKortner
png res_ID_vs_eta.png r1 manage 59.9 K 2011-05-31 - 08:13 OliverKortner
eps res_SA_vs_eta.eps r1 manage 48.7 K 2011-05-31 - 08:13 OliverKortner
png res_SA_vs_eta.png r1 manage 59.8 K 2011-05-31 - 08:13 OliverKortner
eps res_cb_vs_eta.eps r1 manage 48.9 K 2011-05-31 - 08:12 OliverKortner
png res_cb_vs_eta.png r1 manage 59.5 K 2011-05-31 - 08:12 OliverKortner
Topic revision: r42 - 2014-11-14 - GabriellaSciolla

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