Tracking for 2015


Target

Verify the performance of LHCb Tracking algorithms with the new beam conditions in 2015 ($\sqrt{s}$=13TeV, bunch spacing=25,50 ns) and be prepared for various data-taking scenarios.

Useful samples

There are many useful samples in bookkeeping that can be used to perform your studies:

Data Samples

  • 2011, 25ns: /LHCb/Collision11_25/Beam3500GeV-VeloClosed-MagDown/Real Data/Reco11a/90000000 ( Full stream )/RAW : these events are taken without any trigger. No data is actually on disk. If needed, we can request to copy them temporarily to disk.
  • 2012, 25ns: /LHCb/Collision12_25/Beam4000GeV-VeloClosed-MagDown/Real Data/90000000 ( Full stream )/RAW : useful for tracking performance studies
  • 2012, 25ns: /LHCb/Collision12_25/Beam4000GeV-VeloClosed-MagDown/Real Data/Reco14/Stripping20/90000000 ( Full stream )/(various streams) : useful for comparing physics signal yields and efficiencies
  • 2012, High Luminosity: /LHCb/Collision12hl/Beam4000GeV-VeloClosed-MagDown/Real Data/90000000 ( Full stream )/RAW : useful for tracking performance studies
  • 2012, High Luminosity: /LHCb/Collision12hl/Beam4000GeV-VeloClosed-MagDown/Real Data/Reco13g/Stripping20/90000000 ( Full stream )/(various streams) : useful for comparing physics signal yields and efficiencies [beware: Reco13g, not Reco14]
N.B.: The RAW data samples are on tape, they can be duplicated on disk upon request. For tracking studies one can refer to the DST streams in Stripping20.

MC Samples

N.B.: There is an issue with the DST samples. The "Link/Raw/(Detector)/Clusters" containers are not filled, therefore clusters truth-matching is not possible. This samples cannot therefore be used for Tracking performance measurements using the PatChecker algorithm. XDIGI samples need to be used instead.

RunII

  • 13TeV, RunII, MinBias: /MC/Dev/Beam6500GeV-RunII-MagDown-Nu1.9-25ns-Pythia8/Sim08f/30000000 ( minbias )/XDIGI : for minimum bias studies
  • 13TeV, RunII, Physics: /MC/Dev/Beam6500GeV-RunII-MagDown-Nu1.9-25ns-Pythia8/Sim08f/( evtid )/XDIGI : a few physics channels for physics studies
All of this samples are generated for magnet Up and Down and for different running conditions:
  • 25ns: Nu=1.6,1.9
  • 50ns: Nu=1.6,2.7

RunI

  • 8TeV, RunI, MinBias: /MC/2012/Beam4000GeV-2012-MagDown-Nu2.5-Pythia8/Sim08e/Trig0x409f0045 /30000000 ( minbias )/XDIGI : for minimum bias studies
  • 8TeV, RunI, Physics: /MC/2012/Beam4000GeV-2012-MagDown-Nu2.5-Pythia8/Sim08e/Trig0x409f0045 /( evtid )/XDIGI : a few physics channels for physics studies
All of this samples are generated for magnet Up and Down.

Condition Databases

The suggested condition databases for running on these samples are (11/2/2014):

  • CONDDB: cond-20130710
  • DDDB: dddb-20130929-1
  • SIMCOND: sim-20131023-vc-md100, sim-20131023-vc-mu100

Ongoing activities and responsible people

This is a list of specific topics to see who is currently working on what, broader topics and responsible people are listed below.

Topic Description Contact Link
Combinatorics in T-stations Check if hits can be (better) preselected ??? ???
Fitting framework Provide fitting framework for all chi2-fits, vectorisable Manuel Schiller,... ???
Vectorising pat reco Vectorise the hotspots of the pattern recognition Gerhard Raven, ... ???
Speeding up Kalman filter Can we speed up the Kalman filter, using vectorised libraries/code ??? ???
Adaptive windows Can we use adaptive windows in the patreco (depending on position, event multiplicity, ...) ??? ???
Floats Rewrite the patreco using float instead of doubles ??? ???
Online -> Offline tracks Can/should offline tracks be constructed from online tracks? ??? ???
Update / Check params in pat reco Update all parametrisations in the patreco algorithms to latest MC ??? ???

Detailed Wish List

Topic Algorithm Proponent Comment Timescale Started Finished Responsible
Pattern Recognition Fit General Manuel Schiller          
Trade ghost rate for efficiency Velo David Hutchcroft almost at limit        
Lite cluster decoding Velo Kurt Rinnert          
double vs. float Velo Kurt Rinnert          
2nd metal layer effect Velo            
Clustering thresholds Velo            
Improve clustering Upstream Barbara Storaci          
Velo+VeloTT+Forward efficiency loss recovered by matching? Upstream Barbara Storaci          
Code review Upstream Barbara Storaci          
Optimised search regions Upstream Barbara Storaci          
TT addition after Velo+VeloTT+Forward still needed? Upstream Barbara Storaci          
Require confirming stereo hit when adding x hit? Forward Michel De Cian          
"Precluster" layer Forward Michel De Cian          
Better way to sort subranges Forward Michel De Cian          
Region and occupancy dependent search windows Forward Michel De Cian          
TT hit adding smarter and faster Forward Michel De Cian waiting until TrackMatching in 'obsolete' to simplify interface Middle of November yes yes Michel
Pooled allocation for hits Forward Michel De Cian          
floats vs. double Forward Michel De Cian          
AOS vs SOA hits Forward Michel De Cian          
High threshold bit for silicon detectors Forward Michel De Cian          
Ambiguity resolution via pitch residuals? Simfit in x,y? Forward Michel De Cian          
Hit cleaning in busiest region of OT Seeding Manuel Schiller          
Kill unused OT hits early in the reco Seeding Manuel Schiller          
Kill hits from previous/next bunch crossing Seeding Manuel Schiller          
Use wire propagation time? Seeding Manuel Schiller          
Port upgrade studies? Matching Michel De Cian Tuning and some improvements done. Small improvements still possible, if errors correctly propagated from Velo and Seed End of December yes yes Michel
Backport upgrade version? Downstream Michel De Cian basic version backported, gain smaller than expected, investigate... End of year (?) yes   Michel
Improvement of equation of motion of charged particle in magnetic field Kalman Fit Wouter Hulsbergen, Gerhard Raven          
Calculate more quickly energy loss and multiple scattering corrections Kalman Fit Wouter Hulsbergen, Gerhard Raven          
Node/measurement creation, improve the allocation Kalman Fit Wouter Hulsbergen, Gerhard Raven          
TrackProjectors: TrajPoca really needed for straight line hits? Kalman Fit Wouter Hulsbergen, Gerhard Raven          
Matrix operations Kalman Fit Wouter Hulsbergen, Gerhard Raven          
OT hits in high occupancy regions Kalman Fit Wouter Hulsbergen, Gerhard Raven          
OT decoding improvements possible? Kalman Fit Wouter Hulsbergen, Gerhard Raven          
Check tracks for hit overlap very fast? Kalman Fit Wouter Hulsbergen, Gerhard Raven          
Advanced algorithms monitoring (efficiency, timing, ghosts) Monitoring Michel De Cian, Manuel Schiller     yes   Svende
High-level Quantities Monitoring Monitoring            
Tune ghost probability ghost probability Michel De Cian   end of 2014     Paul
Overlap online-offline online-offline Vava Gligorov   end of January 2015     Sascha
Implement improved multiple-scattering correction Kalman Fit Miriam Hess         Miriam

Tracking Algorithms Performance

Task Force: Manuel Schiller, Michel De Cian, Sebastian Neubert.

PrChecker tables

The following tables show the output of the PrChecker for 1000 events of B->K*mumu for different running scenarios:

Additionally it was checked how the behaviour would be for the highest running scenarios when cutting on the SPD multiplicity:

The upstream numbers in all tables are wrong due to a wrong setting.

The following PrChecker tables (5k events) are with Reco15 for 2015 data taking and obtained from Sim08f samples:

For reference the same with the Sim08e samples:

Velo Tracking

Velo Pattern Recognition contacts: David Hutchcroft and Kurt Rinnert

Standalone T reconstruction

T seeding contact: Manuel Schiller

Long Track Reconstruction

There's a presentation by Paul https://indico.cern.ch/conferenceDisplay.py?confId=280286 It can be reproduced with the instruction in Phys/TrackingScripts/TrackEffMCStudies/README. The Brunel options produce two TTrees, one comparing the TrackBestTrackCreator to the TrackEventCloneKiller, one for comparing PatForward with PatMatch.

Forward Tracking

Forward contacts: Michel De Cian

Track Matching

Downstream Tracking

Downstream contacts: Adam Davis, Mike Sokoloff and Mika Vesterinen

Upstream Tracking

VeloTT contacts: Barbara Storaci and Marco Tresch

Clone Killer

Open question: Why are forward tracks preferred over match tracks after the Kalman filter? Better chi2? More hits on track?

Possible Improvements

There are a few studies performed on the tracking for the upgrade that may be ported to the current tracking:

Running the tracking on top of HLT found tracks:

Tracking Efficiency

contact: Michael Kolpin

Detectors Performance

Velo

TT

IT

contact: Mark Tobin

OT

contact: Francesco Dettori and Niels Tuning

Further checks are ongoing on the drift time.

Outer Tracker performance with 25ns has been studied using the data recorded in 2012. These studies are outlined in the Performance of the LHCb Outer Tracker.

Muon

Validation

A tool is needed for validating the reconstruction software. Differences among two reconstruction software versions should be analysed by means of tracking specific quantities and physical quantities. Contact: Svende Braun

(Open) Issues

  • The definition of "from B" and "from C" changed in summer (see Rev 159594). The PatChecker / TrackChecker have been updated on 23.1.2014 to only flag daughter particles from mesons and baryons as "from B" or "from C" (which is the correct definition). Without this update there might be slightly lower efficiencies for these categories.
  • There may be differences between the simulated and actual detector response with 25ns. Investigation with detector and simulation experts is ongoing.
  • The "Link/Raw/(Detector)/Clusters" containers are not filled, therefore clusters truth-matching is not possible on the DST Monte Carlo since Sim08.

Obsolete code

The following classes have not been used since a long time in the tracking and are not forseen to be used in the future. They might become subject to removal (after an announcement and contacting the authors).

All of this code has been put in obsolete (November 15 2014).

Presentations with 2015 tracking contributions

-- MichelDeCian - 30 Jan 2015
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf OT_25-50-75ns.pdf r1 manage 24.2 K 2014-02-02 - 16:06 MaurizioMartinelli OT_25-50-75ns
PNGpng OT_StrawOccupancy.png r1 manage 169.6 K 2014-02-02 - 16:08 MaurizioMartinelli OT_StrawOccupancy
Texttxt PrCheckerMC2012KstmumuMagDown.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown25nsNu15.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown25nsNu19.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown25nsNu26.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown25nsNu26SPD450.txt r1 manage 13.5 K 2014-11-21 - 22:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown25nsNu26SPD600.txt r1 manage 13.5 K 2014-11-21 - 22:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown25nsNu26SPD900.txt r1 manage 13.5 K 2014-11-21 - 22:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown50nsNu27.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown50nsNu34.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown50nsNu48.txt r1 manage 13.5 K 2014-11-05 - 20:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown50nsNu48SPD450.txt r1 manage 13.5 K 2014-11-21 - 22:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown50nsNu48SPD600.txt r1 manage 13.5 K 2014-11-21 - 22:52 MichelDeCian  
Texttxt PrCheckerReco15DevKstmumuMagDown50nsNu48SPD900.txt r1 manage 13.5 K 2014-11-21 - 22:52 MichelDeCian  
Texttxt PrCheckerReco15KstmumuMagDown25nsNu15Sim08e.txt r1 manage 16.3 K 2015-08-19 - 11:01 SaschaStahl  
Texttxt PrCheckerReco15KstmumuMagDown25nsNu16Sim08f.txt r1 manage 16.3 K 2015-08-19 - 11:01 SaschaStahl  
Texttxt PrCheckerReco15KstmumuMagDown25nsNu19Sim08f.txt r1 manage 16.3 K 2015-08-19 - 11:01 SaschaStahl  
Texttxt PrCheckerReco15KstmumuMagDown25nsNu23Sim08e.txt r1 manage 16.3 K 2015-08-19 - 11:01 SaschaStahl  
Texttxt PrCheckerReco15KstmumuMagDown25nsNu26Sim08e.txt r1 manage 16.3 K 2015-08-19 - 11:01 SaschaStahl  
Edit | Attach | Watch | Print version | History: r42 < r41 < r40 < r39 < r38 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r42 - 2015-10-13 - MichelDeCian
 
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    LHCb All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback