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Combined Muon Performance Public Results

This page presents public results about the combined performance for muons in the ATLAS detector. The most recent results come first. This pages has five sections:


Muon Journal Papers

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Muon Conference Notes

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

Preliminary Figures from 2012 Collision Data at 8 TeV

Muon efficiency and muon momentum resolution in 2012 data)

MCP Mass Performance plots (HCP dataset 2012)

Momentum scale and Z lineshape plots for 2012 data (Moriond 2013 dataset)

Muon reconstruction efficiency in 2012 pp collisions (Moriond 2013 dataset)

Preliminary Figures from 2011 Collision Data at 7 TeV

Dependence of the muon performance on pile-up in reprocessed 2011 data

Muon Reconstruction Efficiency using J/ψ

Muon isolation plots

Muon momentum resolution plots

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.
Z Dimuon Resolution

SVG (Scalable Vector Graphics) 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. 		Z Dimuon Resolution

SVG (Scalable Vector Graphics) 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.

Z Dimuon Resolution

SVG (Scalable Vector Graphics) 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.

Z Dimuon Resolution

SVG (Scalable Vector Graphics) 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. 		Efficiency

SVG (Scalable Vector Graphics) 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. 		Efficiencies

SVG (Scalable Vector Graphics) 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. 		Efficiencies

SVG (Scalable Vector Graphics) 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. 		Efficiencies

SVG (Scalable Vector Graphics) 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. 		Efficiencies

SVG (Scalable Vector Graphics) 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. 		Efficiencies

SVG (Scalable Vector Graphics) eps file

Preliminary Figures from 2010 Collision Data at 7 TeV

Preliminary reconstruction efficiency measurement at low transverse momentum with tag and probe at the J/Psi peak - full 2010 data set

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.
Z Dimuon Resolution

SVG (Scalable Vector Graphics) 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.
Z

SVG (Scalable Vector Graphics) 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.
Z Dimuon Resolution with the Muon Spectrometer

SVG (Scalable Vector Graphics) 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.
Reprocessing improvement to Z->mumu resolution

SVG (Scalable Vector Graphics) 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.
Reprocessing improvement to Z->mumu resolution

SVG (Scalable Vector Graphics) 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.
Reprocessing improvement to Z->mumu resolution

SVG (Scalable Vector Graphics) 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. 		phi

SVG (Scalable Vector Graphics) 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. 		phi

SVG (Scalable Vector Graphics) 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. 		phi

SVG (Scalable Vector Graphics) 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).
phi

SVG (Scalable Vector Graphics) eps file

Preliminary Figures from 2009 Collision Data at 900 GeV

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

Blue led  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.
Blue led  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.
Blue led  Collisions were selected considering only paired Bunch Crossing Identifiers and through the timing of MBTS or LAr
Blue led  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
Blue led  Tight cuts on the muon candidates were applied requesting a confirmation in the Inner Detector for all of them
Blue led  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.

SVG (Scalable Vector Graphics) eps file 		phi
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

SVG (Scalable Vector Graphics) eps file 		eta
transverse momentum distribution for muon candidates
The transverse momentum is measured by the Inner Detector.


SVG (Scalable Vector Graphics) eps file 		pt
momentum distribution for muon candidates
The momentum is measured by the Inner Detector.

SVG (Scalable Vector Graphics) eps file 		momentum

Figures for runs 141749 and 141811 (TOROID OFF)

Blue led  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.
Blue led  However, the acceptance is increased due to the fact that even very low momentum muons can traverse the spectrometer.
Blue led  Cathode Strip Chambers are not yet included in the runs 141749 and 141811
Blue led  *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.

run141749 event133538

Track parameter distributions

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

SVG (Scalable Vector Graphics) eps file 		phi
Pseudorapidity distribution for muon candidates
Distribution peaked at large η, as expected for minimum bias p-p collisions

SVG (Scalable Vector Graphics) eps file 		eta
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.

SVG (Scalable Vector Graphics) eps file 		impact parameter
Responsible: atlas-perf-muons-conveners@cernNOSPAMPLEASE.ch
Last reviewed by: Never reviewed

Attachments Attachments
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf 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.
PDFpdf ATL-COM-PHYS-2011-1503.pdf r1 manage 1872.9 K 2011-11-17 - 11:44 OliverKortner  
PDFpdf ATL-COM-PHYS-2011-1504.pdf r1 manage 1752.1 K 2011-11-17 - 11:50 OliverKortner  
PNGpng Dimuon_mass.png r1 manage 16.8 K 2010-07-23 - 20:38 DomiziaOrestano  
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PNGpng Dimuon_mass_896.png r1 manage 16.9 K 2010-08-24 - 12:53 DomiziaOrestano  
Unknown file formateps MUID_combined_id_vs_eta.eps r1 manage 61.9 K 2011-05-31 - 09:07 OliverKortner  
PNGpng MUID_combined_id_vs_eta.png r1 manage 130.5 K 2011-05-31 - 09:08 OliverKortner  
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PNGpng MUID_tight_id_vs_eta.png r1 manage 126.1 K 2011-05-31 - 09:09 OliverKortner  
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PNGpng STACO_combined_id_vs_eta.png r1 manage 135.1 K 2011-05-31 - 09:07 OliverKortner  
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PNGpng STACO_loose_id_vs_eta.png r1 manage 127.8 K 2011-05-31 - 09:08 OliverKortner  
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PNGpng effiID_MCP_vs_eta.png r1 manage 111.4 K 2011-05-31 - 09:07 OliverKortner  
Unknown file formateps effiID_MinBias_vs_eta.eps r1 manage 23.9 K 2011-05-31 - 09:06 OliverKortner  
PNGpng effiID_MinBias_vs_eta.png r1 manage 108.8 K 2011-05-31 - 09:06 OliverKortner  
Unknown file formateps etaMuonsPPt.eps r2 r1 manage 10.6 K 2010-03-23 - 16:17 DomiziaOrestano  
GIFgif etaMuonsPPt.gif r2 r1 manage 12.6 K 2010-03-23 - 16:18 DomiziaOrestano  
Unknown file formateps m12_cb.eps r1 manage 12.4 K 2011-05-31 - 08:10 OliverKortner  
PNGpng m12_cb.png r1 manage 55.1 K 2011-05-31 - 08:11 OliverKortner  
Unknown file formateps momentumMuonsPPt.eps r2 r1 manage 10.3 K 2010-03-23 - 16:19 DomiziaOrestano  
GIFgif momentumMuonsPPt.gif r2 r1 manage 12.9 K 2010-03-23 - 16:20 DomiziaOrestano  
Unknown file formateps plot_Z_M_CB.eps r1 manage 21.1 K 2011-01-18 - 16:37 OliverKortner  
PNGpng plot_Z_M_CB.png r1 manage 23.3 K 2011-01-18 - 16:37 OliverKortner  
Unknown file formateps plot_Z_M_ID.eps r1 manage 20.7 K 2011-01-18 - 16:47 OliverKortner  
PNGpng plot_Z_M_ID.png r1 manage 22.3 K 2011-01-18 - 16:47 OliverKortner  
Unknown file formateps plot_Z_M_MX.eps r1 manage 20.6 K 2011-01-18 - 16:48 OliverKortner  
PNGpng plot_Z_M_MX.png r1 manage 22.7 K 2011-01-18 - 16:49 OliverKortner  
Unknown file formateps ptMuonsPPt.eps r2 r1 manage 10.0 K 2010-03-23 - 16:20 DomiziaOrestano  
GIFgif ptMuonsPPt.gif r2 r1 manage 12.0 K 2010-03-23 - 16:21 DomiziaOrestano  
Unknown file formateps res_ID_vs_eta.eps r1 manage 48.9 K 2011-05-31 - 08:12 OliverKortner  
PNGpng res_ID_vs_eta.png r1 manage 59.9 K 2011-05-31 - 08:13 OliverKortner  
Unknown file formateps res_SA_vs_eta.eps r1 manage 48.7 K 2011-05-31 - 08:13 OliverKortner  
PNGpng res_SA_vs_eta.png r1 manage 59.8 K 2011-05-31 - 08:13 OliverKortner  
Unknown file formateps res_cb_vs_eta.eps r1 manage 48.9 K 2011-05-31 - 08:12 OliverKortner  
PNGpng res_cb_vs_eta.png r1 manage 59.5 K 2011-05-31 - 08:12 OliverKortner  
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Topic revision: r42 - 2014-11-14 - GabriellaSciolla
 
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