Flow Description

If there are ID tracks, loop over them and for each track with pT over 2.5 GeV
  • Perform crude extrapolation to disk or cylinder at the entry to the muon inner stations
  • Correct the momentum of the particle candidate to account for energy loss in the calorimeter using MuidCaloEnergyTool
  • All extrapolations of intersections are done using RungeKutta
  • The algorithm progresses from one combination of distance (inner, middle, etc.) and region (barrel, endcap) to another
  • For each such combination, the information gathered thus far is used to open a road in η/φ, select chambers reachable in the road, select hits in the road, and create segments form these hits. The details depend on the technology (MDT, RPC, TGC, CSC), distance and region
  • The road width depends on our confidence in the extrapolation as estimated using single muon samples. The width is affected by the estimated pT of the candidate, the presence of hits/segments in other parts of the muon spectrometer, etc.
  • Chambers are selected using RegSelSvc where possible, direct enumeration methods where the region selector does not operate
  • The η value of η hits is corrected as a function of the φ of the track before they are tested against the road
  • Segments are built using different algorithms for different technologies
    • The Hough MDT segment maker is used for the MDT stations
    • A simple average point is calculated for the TGC in the inner station
    • A straight line is estimated for the TGC in the middle station. Points that are far from the line (contributing a Χ2 of 10 or more) are succeessively removed from the fit. If there are not enough points (less than 4), a simple average is used here too. In this case the direction of the segment is borrowed from a previous extrapolation
    • RPC middle... outer...
    • CSC...
  • For the inner distance:
    • In the endcap
      • Extrapolate the ID track from the entry to the inner disk to each TGC chamber in the selected list
      • Select TGC hits in the road, estimate the position of the intersection of the candidate track with the inner station. Use the direction of the extrapolated track (only 2 close hits in TGC Inner station) to create a segment (if too few hits?). The intersection derived from this segment will be the starting point for the next step
    • In the barrel
      • Use the intersection of the extrapolated ID track as a starting point
    • Use the intersection from the previous step to open a road and select MDT chambers
      • Check the possibilty of combining the position and direction information from the extrapolated track and the trigger tracklet
    • Extrapolate the best available intersection to each chamber and select MDT hits in a road around it
    • Create caliberated hits (MdtDriftCircleOnTrack) using MdtDriftCircleOnTrackCreator
    • For each MDT station (one or two chambers) build segments using MDT_DHoughSegmentMaker
      • Provide the selection road to the segment maker algorithm
    • The position and direction of the best MDT segment, together with other information, form the intersection is used as a starting point in the next step
    • The CSC is a separate region and trigger chambers cannot be used to help there. A segment in the CSC is used for further extrapolation.
  • ...
  • For the middle distance:
    • Perform fine extrapolation from best Inner result to each trigger chamber in list.
    • Look for hits in trigger chambers, make a segment (also in RPC) get position from it, and direction if the are enough hits or direction of extrapolated track if there are no enough hits.
  • Correct η hits for r(φ of track) .
  • Combine position and direction information from extrapolated track and trigger tracklet. We found that the trigger track is much better, and currently use it to extrapolate to MDT chambers.
  • Perform fine extrapolation to each MDT chamber in list, using the best information available (trigger chamber or extrapolated ID track)
  • Find digits (and tubes?) in road (correct endcap hits for r(φ)) prepare MdtDriftCircleOnTrack and send hits and road to Hough segment maker.
    • The position and direction of the MDT segment is used together with other info to do fine extrapolation to the next station.
  • For Outer distance:
    • Perform fine extrapolation from best Middle result to each trigger chamber in list (barrel only).
    • Look for hits in trigger chambers, make a point in RPC, get position from it, and direction from extrapolated track (only 2 hits).
  • Correct η hits for r(φ of track) .
  • Combine position and direction information from extrapolated track and trigger position (check if this helps).
  • Perform fine extrapolation to each MDT chamber in list, using the best information available (hits in RPC or previous best extrapolated)
  • Find digits in road (correct endcap hits for r(φ)) prepare MdtDriftCircleOnTrack and send hits and road to Hough segment maker.
    • The position and direction of the MDT segment is used together with other info to do fine extrapolation to the next station.
  • The result is hits and segments in each station.
  • ANN to give quality factor
  • Fit to get new track parameters (if high pT).

Things we need in the ntuple (and therefore in class Candidate)

  • ID pT, position (η, φ) and direction (η, φ)
  • Rough extrapolation position (η, φ) and direction (η, φ) for each distance/region
  • Fine extrapolation position (η, φ) and direction (η, φ) for each station/technology
  • Position (η, φ) and direction (η, φ) of segment for each station/technology
  • Corrected position (η, φ) and direction (η, φ) for each station/technology
  • Number of hits for each station/technology/readout direction
  • List of hits η/φ
  • Segment information quality, position (η, φ) and direction (η, φ) for each station/technology/readout direction

Todo

Study of performance (Natasha)

  • Check for 4, 10, 100 GeV
  • Distance from ID and TGC to inner MDT hits and to resulting segments.
  • Distance from inner ID, TGC and MDT to middle TGC/RPC and MDT hits
  • Best info to extrapolate to middle distance TGC
  • Best info to extrapolate to middle distance MDT after TGC/RPC segment in middle
  • Distance from middle ID, TGC/RPC and MDT to outer RPC and MDT hits
  • Best info to extrapolate to outer distance RPC
  • Best info to extrapolate to outer distance MDT after RPC segment in outer
  • What quantities go into ANN

Study of ID tracking (Ofrit)

  • Which inner tracking give the most efficiency and purity for ID muon tracks?
  • Which inner tracking extrapolates best to muon spectrometer and gives the best final muon efficiency and purity?

Program evolution (Zvi)

Assigned to Due date Description State Close Date Notify  
ZviTarem 2006-06-01 Hits in segments flag 2006-06-01   edit
ZviTarem 2006-07-04 New package structure   edit
ZviTarem 2006-07-04 Add RPC segments   edit
ZviTarem 2006-06-10 Add extrapolation of MDT segment from distance to distance 2006-06-09   edit
ZviTarem 2006-07-04 Detect empty chambers in the road - flag when there are only empty chambers   edit
ZviTarem 2006-07-04 Intersection of MDT segment takes η from segment, φ form other sources   edit

Hough (Didi)

  • Check Χ2 calculation – removal of outliers
  • Look at Χ2 vs distance between multi layers
  • Add in segment fit quality how many multi layers are included in segment
  • Any news on CSC? Do we need to prepare anything in MuGirl?
Edit | Attach | Watch | Print version | History: r7 < r6 < r5 < r4 < r3 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r7 - 2020-06-18 - MaximKonyushikhin
 
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