v4-16-Release: bug reports, committed fixes and proposed changes P. Hristov 21/05/2009 Weekly offline meeting
Committed changes • #50301 Please install new AliTPCPreprocessor in Release � • #50274 Wrong orientation of TPC clusters (Simulation with Geant4) � • #49055 Artifact in the Z vertex distribution reconstructed with T0 � • The new RAW format: patch exists �
Proposed fixes • #50614: 4-prong D0-> Kstar pi pi not switched off for kHadronicDWithout4Bodies. – From rev. 32473 • #50598: SHUTTLE subprocessor – From rev. 32379 • bug #44266: Introduce the Bethe-Bloch function in AliMathBase – From rev. 32438 • bug #48080: Dip at zero in the distribution of Delta-phi and d: PbPb events – From rev. 32418,32424, 32439. More changes expected.
New reports • #50665 CTP interaction records to be added to ESD? • #50609 esd_tracks.C displays events wrongly when simulated with neg mag field • #50456 Macros and AliRoot for multiple EMCAL productions • #50446 LocalBoardId [MUON cosmic production] • #50437 MUON QA checkers not working [MUON cosmic production] • #50436 MUON DE0510 mapping problem [MUON cosmic production] • #50435 MUON Station2 mapping/geometry problem [MUON cosmic production] • #50432 MUON cosmic RecoParam [MUON cosmic production] • #50430 MUON KillMap [MUON cosmic production] • #50391 Implementing the possibility to correct the tracking for non-zero transverse components of the B-field. (Black = v4-16-Release, Blue=trunk)
Reports from the last week • #50416 TRD tracks not propagated to the outer wall of TPC • #50317: Correct AliGenPythia for B-jet studies • #50254 Additional info in ESD track for TRD PID [request] • #50225 AliAODHandler doesn't work correctly with merged events • #50174 Index out of bound in TPC digitization for ppbench (Black = v4-16-Release, Blue=trunk)
High priority (my selection) • #49416 ClusterFinder - too many deconvoluted clusters – No news • #48981 Problem in "on the flight" V0 finder – No news
Active investigations:#48080 Dip at zero in the distribution of Delta-phi and d: PbPb events • The origin of the problem is identified: the function AliITStrackV2:GetLocalXat and AliITStrackV2:GetLocalZat had a protection that excluded the propagation if the radius was smaller than the estimated DCA. – Improved protections were provided by Ruben & Martin • A feature was corrected: mismatch between the current phi of the track momentum and position (Andrea) • Additional investigations of the propagation and material corrections • More news during the PWG1 meeting
Old slides: 14/05/09
Active investigations: #47881 Position of outer track parameter not symmetric and not “outer” 1. The AliTPCtrack::PropagateTo function was modi fi ed. In case of step outside of TPC volume the track is not propagated.(The material description is not correct) 2. For unknown reason the TRD updates the Outer parameters even being outside of the acceptance. The code responsible was not localized. 3. Running the same reconstruction code without and with outer detectors the ef fi ciency to re fi t decrease from 100 % to 98 %. The effect is visible mainly for big theta. The TPC outer parameters have to be backuped in the AliESDfriend and incase of big difference (>n sigma) between TPC backup and current AliESDtrack parameters have to be replaced.
Active investigations: #49294: High-pt fake tracks are produced in 0 < phi < 30 0. I agree with Youri that we should apply proposed cut (on the relative precision of 1/PT). On top we have to minimize tails in pt pulls. The tail will de fi ne our cut. 1. The width of the pt pulls for tracks not decaying in the TPC is around(1,1.1) (TPC stand alone) 2. In case the particle decays inside of the TPC signi fi cant the tails of the distribution are more signi fi cant and the width is two times bigger. 3. The deterioration also visible in case particle decays inside of the TRD and the TRD info is used for re fi t. To be done: 1. Backup TPC outer information in ESD friend track and start TPC re fi t from this point if the mismatch between current param. and backup is bigger than n-sigma threshold. 2. 2. Check all high pt tracks for kink point which can cause the tails in 1/pt residuals.
Active investigations: #44264: Shift in the reconstructed PT Observed pt shift and strong dependence of this shift on the theta is explained by not taking the Br and Br fi component of the mag fi eld into account in AliExternalTrackParam::PropagateTo. It is not detector related. The correction for p_t can be roughly estimated deltapt/pt ~ pz/pr * Br/Bz The fact that the effect is not detector speci fi c can be demonstrated using the exact MC track references instead of the detector clusters in the reconstruction.(The code AliMCTrackingTestTask::FitTrackRefs+see attached picture.) Conclusion: 1. ALL components of mag fi eld should be taken into account in the propagate method. 2. Effect is proportional to the Br/Bz which is on the level of 0-2% 3. The effect of the vxB effect to the angular and position shift can not beneglected 4. Somebody should impliment as soon as possible correct PropagateTo method -not approximation - as all parameters are affected.
Active investigations: #46277: TPC z shift The theta dependent z shift for track extrapolated to the TRD is observed also from the fi t of MC data in case the Br and Br fi fi eld is neglected during track propagation. The effect is also pt dependent, basically the track is de fl ected by a fraction a curvature in y direction. Using tracks from your production /lustre/alice/local/TRDdata/SIM/P-Flat/TRUNK I got the slope about -0.4 mm/tan(theta) for tracks bellow 1 GeV.For tracks over 2 GeV the slope ( from MC fi tting) was negligible. I do not say that this is full explanation, but currently the fi rst task is to implement correct Propagate method.
Active investigations: #46277: TPC z shift I added new data memebers to the AliESDfriend track AliExternalTrackParam * fTPCOut; // tpc outer parameters AliExternalTrackParam * fITSOut; // its outer parameters AliExternalTrackParam * fTRDIn; // trd inner parameters There are 2 reasons why I want to add them. 1. I can discard the information from outer detectors in case there is big chi2 mismatch between fTPCout and current ESDtrack parameters. (because of kink decays, big -non consistent material budget correction, and also bugs) 2. We can do QA - matching of the track parameters from different detectors.
Active investigations • #48080 Dip at zero in the distribution of residuals (phi-angle, impact parameter in the transverse plane): PbPb events – Investigated by Martin, Andrea,Yuri and Francesco – Reproduced with pp events when vertexer Z is used instead of vertexer 3D. – Doesn’t depend on the XY position of the vertex: forcing X=0, Y=0 in vertexer 3D doesn’t reproduce the problem. – Using (0,0,0) as vertex doesn’t reproduce the dip (possibly because of the smearing). – Switching off AliITStrackV2::Improve method (return at the first line) “cures” the dip with vertexer Z. Confirmed. – Still a lot of work needed…
Old slides 07/05/09
Previous reports • #49538 PbPb bench crash:F-TGeoPcon::ComputeBBox: Wrong section order – AliSHILv3 has to be fixed • #48898 Different track indices in the ESD kink loop and the ESD track loop – “Marian knows how to fix the problem”. Second reminder is sent. • #48748 Number of foundable clusters in TPC needs refinement – No news • #48360 Every MC production job writes an object back to OCDB. Temporary modification in sim.C/rec.C
Previous reports II • #44511: Eta dependency of PID efficiency � dE/dx not OK � #46796: Multiply reconstructed tracks (phi = 0 and 180 deg) � ~1% fake tracks. This is consistent with the particle decays when some clusters from the daughter track are assigned to the mother one or vice versa. � More investigations?
Work in progress (?) � #46278: Bug/artifact in SPD tracklet finding � Caused by the selection on DeltaPhi in the ITS vertexer 3D. PB to decide. � #46372: Primary vertex reconstruction: events with multiple primary vertices � Preliminary results shown � The updates in the ESD available in the trunk Proposal: introduce it when we start pileup production with v4-16-Release
Work in progress (?) #47452: TPC drift velocity correction � (was TPC-TOF matching in LHC08d raw-data reconstruction) Affects not only TOF matching but also all the other barrel detectors � Laser and ITS/TPC matching algorithms will give the absolute Vdrift (under development) � Low number of laser tracks prevents (~30 instead of ~300/event) is an obstacle for the � calibration #45031: LHC machine parameters to go into GRP � Presented at the physics board. My understanding of the decision: take all the information. � Proposal: implementation upon the PB's decision, not urgent for current MC production
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