Please do not add figures on your own. Contact the the inner tracking combined performance coordinators (atlasperfidtrackingconveners@cernNOSPAMPLEASE.ch) in case of questions and/or suggestions.
The following plot is commented in ATLASCOMPHYS2011643, other plots from that document have been removed because they are superseded by the May 2012 alignment systematics page.
Subsystem level, “Level One”, alignment corrections performed on a run by run basis starting from a common set alignment constants. The corrections shown are for translations in the global x direction. Large movements of the detector are measured after hardware incidents. In between these periods little (<1μm) movement is observed indicating that the detector is generally very stable. At this stage run by run corrections will only be applied during data reprocessing but in the future this type of correction will be applied during the ATLAS reconstruction calibration loop. In between runs:
 eps version of the figure 
The following plots are commented in ATLASCOMPHYS2011865 with updates from ATLCOMPHYS20111247
They show the Z mass reconstructed with ID only tracks using the alignment prepared for the summer 2011 reprocessing, which correct for a curl weak mode observed in data.
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011. Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011.
Both tracks in the barrel region η<1.05 Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011.
At least one track in the barrel region η<1.05 outdated plot, please use the one above with both tracks in the barrel Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011.
Both tracks in the endcap A region 1.05 < η < 2.5 Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011.
At least one track in the endcap A region 1.05 < η < 2.5 outdated plot, please use the one above with both tracks in endcap A Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011.
Both tracks in the endcap C region 2.5 < η < 1.05 Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Invariant mass distribution of Z → μμ decays, where the mass is reconstructed using track parameters from the Inner Detector track of the combined muons only, using about 702 pb^{1} of data collected during spring 2011.
At least one track in the endcap C region 2.5 < η < 1.05 outdated plot, please use the one above with both tracks in endcap C Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
Mean Z invariant mass versus φ for positive and negative muons, respectively. The mass distributions are fitted in RooFit using an unbinned maximum likelihood fit of a BreitWigner distribution, describing the intrinsic Z width, convolved with a Crystal Ball function as resolution function. Only Z candidates with a mass [71, 111] GeV are used.
Both tracks in the barrel region η < 1.05 Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
eps version of the figure  
Mean Z invariant mass versus φ for positive and negative muons, respectively. The mass distributions are fitted in RooFit using an unbinned maximum likelihood fit of a BreitWigner distribution, describing the intrinsic Z width, convolved with a Crystal Ball function as resolution function. Only Z candidates with a mass [71, 111] GeV are used.
Both tracks in the endcap A region 1.05 < η < 2.5 Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
eps version of the figure  
Mean Z invariant mass versus φ for positive and negative muons, respectively. The mass distributions are fitted in RooFit using an unbinned maximum likelihood fit of a BreitWigner distribution, describing the intrinsic Z width, convolved with a Crystal Ball function as resolution function. Only Z candidates with a mass [71, 111] GeV are used.
Both tracks in the endcap C region 2.5 < η < 1.05 Ideal alignment performance based on Monte Carlo is compared to observed performance of data processed with spring 2011 alignment and data processed with updated alignment constants.  eps version of the figure 
eps version of the figure 
D* distributions 

The following plots show distributions of D* and D0 candidates that are selected as follows:
 
This plot shows the mass difference between the D* and the D0 candidates in the signal region, i.e. the region where m(Kpi)1.865 GeV < 20 MeV. A fit using a data+background hypothesis yields 257 + 36 D* events. The reconstructed mass difference of 145.56+0.12 MeV agrees with the PDG value of 145.4 MeV. The width is 0.78+0.15 MeV. 
eps version of the figure 
This plot shows the mass difference between the D* and the D0 candidates in the sideband region, i.e. the region where 100 MeV < m(Kpi)1.865 GeV < 200 MeV. 
eps version of the figure 
This plot shows the invariant mass of the K and the pi for D* candidates selected via the mass difference (delta_m) between the D* and the D0: 143.9 MeV < delta_m < 146.9 MeV. A fit with a sum of a constant and a Gaussian yields 262+40 events inside the peak. The mean of the Gaussian is 1869.2+2.4 MeV which is close to the PDG value of 1864.8 MeV. The width is 13.9+2.3 MeV. 
eps version of the figure 
This plot shows the invariant mass of the K and the pi for D* candidates in the D* sideband region (150 MeV < delta_m < 170 MeV). 
eps version of the figure 

Invariant mass distributions 

This plot shows the invariant mass distribution of two track vertices found with the ATLAS standard V0 vertex finding code
in the range 400 to 800 MeV. No mass constraint is applied during the vertex fit. The two tracks are required to have opposite charge,
more than six silicon hits each and a transverse momentum greater than 100 MeV.
In addition, the distance of the reconstructed secondary vertex to the primary vertex has to be larger than 0.2 mm in the transverse xy (=R phi) plane.
Furthermore, a cut is applied to require that the flight path of the V0 candidate points back to the interaction point. The selection is applied on the angle in the transverse plane between the flight direction, defined from the line from the primary vertex to the secondary vertex, and the momentum sum of the two tracks.
The invariant mass is calculated assuming that both tracks are pions.

eps version of the figure 
This plot is similar to the previous plot (one above). In addition, however, it shows the invariant mass measured in data
for all two track vertex combinations (i.e. no cut on the flight distance or the angle to the flight direction of the reconstructed vertex).

eps version of the figure 
This plot shows the invariant mass distribution of two track vertices found with the ATLAS standard V0 vertex finding code. No mass constraint is applied during the vertex fit. The two tracks are required to have opposite charge,
more than six silicon hits each and a transverse momentum greater than 100 MeV.
In addition, the distance of the reconstructed secondary vertex to the primary vertex has to be larger than 0.2 mm in the transverse xy (=R phi) plane.
Furthermore, a cut is applied to require that the flight path of the V0 candidate points back to the interaction point. The selection is applied on the angle in the transverse plane between the flight direction, defined from the line from the primary vertex to the secondary vertex, and the momentum sum of the two tracks.
Note, this vertex selection is identical to the one used for the K shorts.
The invariant mass is calculated assuming that the positively charged track is a proton and the negatively charged track is a pion.

eps version of the figure 
This plot is similar to the previous plot (one above). In addition, however, it shows the invariant mass measured in data
for all two track vertex combinations (i.e. no cut on the flight distance or the angle to the flight direction of the reconstructed vertex).

eps version of the figure 
This plot shows the invariant mass distribution of two track vertices found with the ATLAS standard V0 vertex finding code. No mass constraint is applied during the vertex fit. The two tracks are required to have opposite charge,
more than six silicon hits each and a transverse momentum greater than 100 MeV.
In addition, the distance of the reconstructed secondary vertex to the primary vertex has to be larger than 0.2 mm in the transverse xy (=R phi) plane.
Furthermore, a cut is applied to require that the flight path of the V0 candidate points back to the interaction point. The selection is applied on the angle in the transverse plane between the flight direction, defined from the line from the primary vertex to the secondary vertex, and the momentum sum of the two tracks.
Note, this vertex selection is identical to the one used for the K shorts.
The invariant mass is calculated assuming that the positively charged track is a pion and the negatively charged track is an antiproton.

eps version of the figure 
This plot is similar to the previous plot (one above). In addition, however, it shows the invariant mass measured in data
for all two track vertex combinations (i.e. no cut on the flight distance or the angle to the flight direction of the reconstructed vertex).

eps version of the figure 
Inner Detector Material Studies 

Several different geometries are used to compare simulated samples
with data. The nominal sample is the default comparison, as the
material model used in simulation is also used in reconstruction. The
additional samples scale structures in the Inner Detector to produce roughly
10% and 20% more material in the simulation in terms of radiation length.
 
Fitted Kshort mean as a function of the decay radius for data and MC simulation. 
eps version of the figure 
Fitted Kshort mean as a function of the decay radius for various MC simulated material descriptions. 
eps version of the figure 
Average Number of Hits on Track in 900 GeV Data 

Plots comparing the average number of silicon hits on track between 900 GeV data and NonDiffractive Minimum Bias Monte Carlo Simulation


Comparison between number of pixel hits on reconstructed tracks in 900 GeV data and NonDiffractive Minimum Bias Monte Carlo Simulatio.
The plot shows the eta distribution in which the increase in the number of hits in the end cap region is clearly visible. The asymmetry in eta is due to the location of disabled modules
There was a problem in the yaxis labeling (shift of 0.5 in the number of hits) which has been corrected on 08/02/10. Please use only the new version! 
eps version of the figure 
Comparison between number of pixel hits on reconstructed tracks in 900 GeV data and NonDiffractive Minimum Bias Monte Carlo Simulation.
The plot shows the phi distribution. Again the location of the disabled modules is visible. The slight disagreement at the percent level is expected to be caused by displacement in xy of the beam spot in simulation.
There was a problem in the yaxis labeling (shift of 0.5 in the number of hits) which has been corrected on 08/02/10. Please use only the new version! 
eps version of the figure 
Comparison between number of SCT hits on reconstructed tracks in 900 GeV data and NonDiffractive Minimum Bias Monte Carlo Simulation.
The plot shows the eta distribution in which the increase in the number of hits in the end cap region is clearly visible. The structure of the SCT disks is reproduced by the simulation.
There was a problem in the yaxis labeling (shift of 0.5 in the number of hits) which has been corrected on 08/02/10. Please use only the new version! 
eps version of the figure 
Comparison between number of SCT hits on reconstructed tracks in 900 GeV data and NonDiffractive Minimum Bias Monte Carlo Simulation.
The plot shows the phi distribution.
There was a problem in the yaxis labeling (shift of 0.5 in the number of hits) which has been corrected on 08/02/10. Please use only the new version! 
eps version of the figure 
Figure description ...  figure 
Particle Identification 

Pixel dE/dx plot calculated using the Pixel cluster charge, and the track’s angle to determine the dx. The maximum charge contribution is skipped when the mean is obtained.
This is to limit the Landau tail. The dE/dx is divided by the silicon density.
 
Pixel dE/dx plots with Lambda(bar) selection

eps version of the figure 
Pixel dE/dx plots with Lambda(bar) sideband selection

eps version of the figure 
The cosmic ray data plots below are a subset of the ID approved cosmic ray data plots
ID track parameter resolutions 

Cosmics muons traverse the whole Inner Detector and thus leave hits in the upper and lower parts of the detector. By dividing the track to its upper and lower half according to the value of the y coordinate of hits on track and refitting both hit collections, two collisionlike tracks originating from the same cosmic muon are obtained. After alignment, track parameter resolutions are studied by comparing the difference (residual) of the track parameters at the perigee point. Since both tracks have an associated error, the quoted resolution is the RMS of the residual distribution of the particular track parameter divided by square root 2. The track parameter resolutions are studied dependant on variables like the pT or the d0 of the tracks. Shifted mean values of the residual distributions can be a sign of systematic detector deformations. The following distributions show data from runs 91885,91888,91890,91891 and 91900 taken in 2008. The tracks have been refitted using Athena release 15.0.0.7 (Tier0).
The following cuts have ben applied per track (if not stated otherwise):
Additionally only events with an event phase between 5 and 30 ns are accepted to ensure proper timing of the subdetectors. The plots show comparisons of tracks using the full Inner Detector (silicon and TRT detectors, closed triangles), only the silicon subdetecors (open triangles) together with tracks from cosmic simulation using the full Inner Detector (stars). The requirement of at least 25 TRT hits is dropped for silicon only tracks. However, the cut on the event phase is retained to ensure proper timing and the comparability of the analyzed sets of tracks. There is no cut on the event phase for simulation events since the jitter in cosmic trigger timing is not simulated.  
Transverse impact parameter resolution as a function of pT. In the low pT region, the resolution is dominated by multiple scattering effects. At higher values, the resolution is flat. Taking into account the TRT information improves the resolution. The difference to the MC curve indicates the remaining mislaignment. 
eps figure 
Transverse impact parameter resolution as a function of d0 itself. For this plot the d0 cut is released to 120 mm and the minum number of Pixel hits is set to one. In general the resolution for full ID tracks is better. The resolution is better in the central d0 region due to more Pixel layers crossed and less spread clusters in the Pixel detector. Dips are seen if the d0 of the tracks equal the radii of the pixel layers (indicated by dashed lines). Since the d0 is in these cases very close to a hit on a Pixel layer, the extrapolation to the perigee point is very small and the resolution improves. The MC distributions confirms the observed behaviour. 
eps figure 
Mean of the transverse impact parameter distribution as a function of pT. The expected value of the mean is 0 as confirmed by the MC distribution. In data a shift is seen for full ID and silicon only tracks. The shift increases with higher pT. 
eps figure 
Mean of the transverse impact parameter distribution as a function of d0 itself. For this plot the d0 cut is released to 120 mm and the minum number of Pixel hits is set to one. The expected value of the mean is 0 as confirmed by the MC distribution. In data a shift is seen for full ID and silicon only tracks. The shift is biggest in the central d0 region. 
eps figure 
Relative momentum resolution as a function of pT. The relative momentum resolution increases with higher pT due to stiffer tracks and a more difficult measurement of the sagitta. Including information from the TRT extends the lever arm and helps improving the resolution especially at high pT values. The difference to the MC curve indicates the remaining misalignment. 
eps figure 
Mean of the relative momentum distribution as a function of pT. The expected value of the mean is 0 as confirmed by the MC distribution. In data a shift is seen for full ID and silicon only tracks. The shift increases with higher pT. 
eps figure 
Resolution of the azimuthal angle as a function of pT. In the low pT region, the resolution is dominated by multiple scattering effects. At higher values, the resolution is flat. Taking into account the TRT information improves the resolution. The difference to the MC curve indicates the remaining mislaignment. 
eps figure 
Resolution of the polar angle as a function of eta. The resolution of the polar angle theta improves at larger eta due to broader pixel clusters that allow a more precise position measurement. Since the TRT effectively does not measure the z coordinate in the barrel region, the resolutions are equal for silicon only and full ID tracks. The difference to the MC curve indicates the remaining misalignment. 
eps figure 
Figure description ...  figure 
Responsible: ChristianSchmitt
Last reviewed by: Never reviewed
I  Attachment  History  Action  Size  Date  Who  Comment 

eps  dEdx_LambdaSelection.eps  r1  manage  155.5 K  20110615  18:37  AttilioAndreazza  
png  dEdx_LambdaSelection.png  r1  manage  30.7 K  20110615  18:37  AttilioAndreazza  
eps  dEdx_LambdaSidebands.eps  r1  manage  125.4 K  20110615  18:38  AttilioAndreazza  
png  dEdx_LambdaSidebands.png  r1  manage  28.9 K  20110615  18:38  AttilioAndreazza 