Current Status of MDC Track Reconstruction MdcPatRec

1. Current Status ofMDC Track ReconstructionMdcPatRec Zhang Yao , Zhang Xueyao 2005-09-07

2. Content • Outline of Mdc pattern recon. • Track parameters stored to TDS • Problem in segment finding • Latest result • To do • Summary yzhang@hepg.sdu.edu.cn

3. BESIII Main Drift Chamber (MDC) yzhang@hepg.sdu.edu.cn

4. Packages • MdcTrkRecon Track-finding and fitting package • BesGeom (NOT service anymore) Interface of MdcGeomSvc • TrkBase Core classes for common tracking code. • TrkFitter Core classes for charged-particle tracking • MdcData Hit and Hot • ProbTools The chisq-consistency support • MdcRecoUtil Other classes used in Reconstruction • ProxyDict Provide a data store • MdcCalib t->d calibration of the Mdc • Bfield Modeling the magnetic field yzhang@hepg.sdu.edu.cn

5. Segment finding and fitting (2004-12) • Track Finding : 2-D tracking • (2005-04) Track Finding : 3-D tracking (2005-04) • Debug • (now) Reconstruction Status yzhang@hepg.sdu.edu.cn

6. Sequence of Segment Finding Form groupword of 8 wires Try 4 hit and 3 hit patterns Do line fit to segments Store segment lists yzhang@hepg.sdu.edu.cn

7. Combine Axial segs to circle track • Circle Fitting Combine Stereo segs to helix track • Helix Fitting Sequence of Track Finding yzhang@hepg.sdu.edu.cn

8. Track Object • RecoTrk : a track object • TrkRep : path-description object • HitOnTrack (HOT) : list of hits yzhang@hepg.sdu.edu.cn

9. Track Parameter • Babar • BesIII yzhang@hepg.sdu.edu.cn

10. Track parameter conversion yzhang@hepg.sdu.edu.cn

11. Store tracks to TDS MdcTrack • 5 track parameters • position of pivot //?? • error matrix for track parameters • chi square of helix fit • number of degree of freedom for the fit • number of total hits contained • number of stereo hits contained • mass of this particle //?? Pid • hit list of the track • phi value at track terminated point (Thank Wang Liangliang ‘s help!) • status flag yzhang@hepg.sdu.edu.cn

12. Store tracks to TDS MdcRecHit • drift distance left • drift distance right • error of drift distance left • error of drift distance right • contribution to chi square • flag indicating left or right • MDC identifier • corrected ADC • corrected TDC • tracks containing this hit • status flag yzhang@hepg.sdu.edu.cn

13. Interface • DriftDist = 1.0e-4*40.0*driftTime;//cm • MdcHit::driftDist(tof, ambig, entranceAngle, dipAngle, z) • MdcHit::driftDist(bunchTime, ambig) • bunchTime+crudeTof • Sigma =0.013; //cm • MdcHit::sigma(driftdist, ambig, entranceAngle, dipAngle, z) • MdcHit::sigma(driftdist, ambig) • T0 = 0.0 • Bfield = BFieldFixed(0.0,0.0,1.0) yzhang@hepg.sdu.edu.cn

14. MdcPatRec Documentation http://koala.ihep.ac.cn/~zhangy/MdcPatRecDoc02/index.html yzhang@hepg.sdu.edu.cn

15. σ = 21 MeV / c σ = 12mm Preliminary Results for 1.0 GeV μ(2005-05) • Released in boss 4.2.0 • Tracking efficiency:80% • Distributionof and after 3-D helix tracking yzhang@hepg.sdu.edu.cn

16. clockwise (0,5) (3,5) (1,5) (2,5) (3,4) (1,4) (2,4) (0,4) (0,3) (3,3) (1,3) (2,3) (0,2) (3,2) (1,2) (2,2) (3,1) (2,1) (0,1) (1,1) (1,0) (3,0) (2,0) (0,0) Modify segment construct • The efficiency of segment finding rely on “neighbor”s finding • Original • construct 8 bit groupword according to a reference wire by id • CAN NOT construct by wire id in superlayer 1~5 yzhang@hepg.sdu.edu.cn

17. Layer id 3 7 6 5 2 4 3 neighbor wire 1 2 neighbor wire 0 1 0 Modify segment construct • Use phi of reference wire get “neighbors” • Take 2 reference wire • Layer 2 and layer 0 take No. 2 wire as reference wire • Layer 3 take No. 4 wire as reference wire yzhang@hepg.sdu.edu.cn

18. Layer id 1 1 0 1 0 1 3 1 0 2 1 0 Modify segment construct • Verify the segment • All segments can pass this test • Almost all hits can form segment • NEED check ambiguity Phi of No. 1 wire yzhang@hepg.sdu.edu.cn

19. Result for 1.0 GeV μ (2005-07) • Tracking efficiency > 99% • Distributionof and after 3-D helix tracking σ = 1.9mm = 6 Mev/c yzhang@hepg.sdu.edu.cn

20. One MC Truth Hit Lost segments at –X • Do a line fit to segment. • The domain of is • Huge chisq in –x • If hits in segment cross –x axis • and < 0 • All segments cross –x can be found • Thank Yu Guowei ‘s help! yzhang@hepg.sdu.edu.cn

21. Latest result of MdcPatRec (2005-09) • MC events • P : 1GeV single track • cos(theta) : (-0.8 0.8) • Wire resolution : smeared with 130 mocron • Particle: muon+,e+ • BESIII’s goal: yzhang@hepg.sdu.edu.cn

22. = 5.8 Mev/c = 4.9 Mev/c = 0.125mm e(+) smeared 1 track efficiency >99.8% Mean = 46.25 yzhang@hepg.sdu.edu.cn

23. e(+) smeared 2 track efficiency >99.8% Mean = 0.45mm = 1.89mm Mean = 44.38 yzhang@hepg.sdu.edu.cn

24. = 5.7 Mev/c = 4.6 Mev/c = 0.125mm Muon(+) smeared 1 track efficiency >99.8% Mean = 45.78 yzhang@hepg.sdu.edu.cn

25. Muon(+) smeared 2 track efficiency >99.8% Mean = 0.4mm = 1.88mm Mean = 44.36 yzhang@hepg.sdu.edu.cn

26. To Do • Sign of d0 • Pivot and FiTem • Store status and residual to TDS • Lost hits of inner layers • Shift of d0 • Spacial resolution • Hit ambiguity • Sigma and Bfield Interface • Find detector concerned value in code • Delete AList ,Pdt, ProxyDict … in my own package yzhang@hepg.sdu.edu.cn

27. Summary • Released in boss 4.3.0 • Almost all track parameters have been put into TDS • Modify some algorithm in segment finding • Reconstruction results are acceptable • Much work to do with algorithm and code yzhang@hepg.sdu.edu.cn

28. Thank you!