Recent results from Kalman track fitting WANG Dayong Oct.26,2005

outline  Progress and status of KalFit  Some words for memory leakage problem  Present performance of the package

Progress and status of KalFit I.Software re-arrange and evolvement II.Improved event model for TDS and DST III.Calculation of path length total&in each layer IV.Performance study and detailed debugging V.Memory leakage VI.Running with MdcTrkRecon VII.Running together with TrkReco

int m_id; float m_mass; // mass assumption during the fit float m_length; //track path length from closest point to coord. origin to the last hit float m_tof; // time of flight correspond to length; int m_nhits; // number of total hits contained int m_stat; // status flag float m_chisq[2]; // chi square of fit 0:filter 1:smoother float m_ndf[2]; // degree of freedom for the fit 0:filter 1:smoother float m_pathl[43]; // path length in each layer HepVector m_zhelix; // 5 track parameters at zero point HepPoint3D m_zpivot; // position of pivot at zero point HepSymMatrix m_zerror; // error matrix at zero point HepVector m_fhelix; // 5 track parameters at 1st hit HepPoint3D m_fpivot; // position of pivot at 1st hit HepSymMatrix m_ferror; // error matrix at 1st hit HepVector m_lhelix; // 5 track parameters at last hit HepPoint3D m_lpivot; // position of pivot at last hit HepSymMatrix m_lerror; // error matrix at last hit Old reconstruct ion event model

int m_id; float m_mass[5]; // mass assumption during the fit float m_length[5]; //track path length from closest point to coord. origin to the last hit float m_tof[5]; // time of flight correspond to length; int m_nhits[5]; // number of total hits contained int m_stat[5]; // status flag float m_chisq[2][5]; // chi square of fit 0:filter 1:smoother float m_ndf[2][5]; // degree of freedom for the fit 0:filter 1:smoother HepVector m_zhelix; // 5 track parameters at zero point for pion HepSymMatrix m_zerror; // error matrix at zero point for pion HepVector m_zhelix_e; // 5 track parameters at zero point for electron HepSymMatrix m_zerror_e; // error matrix at zero point for electron HepVector m_zhelix_mu; // 5 track parameters at zero point for muon HepSymMatrix m_zerror_mu; // error matrix at zero point for muon HepVector m_zhelix_k; // 5 track parameters at zero point for kaon HepSymMatrix m_zerror_k; // error matrix at zero point for kaon HepVector m_zhelix_p; // 5 track parameters at zero point for proton HepSymMatrix m_zerror_p; // error matrix at zero point for proton HepVector m_lhelix; // 5 track parameters at last hit for pion HepSymMatrix m_lerror; // error matrix at last hit for pion HepVector m_lhelix_e; // 5 track parameters at last hit for pion HepSymMatrix m_lerror_e; // error matrix at last hit for pion HepVector m_lhelix_mu; // 5 track parameters at last hit for pion HepSymMatrix m_lerror_mu; // error matrix at last hit for pion HepVector m_lhelix_k; // 5 track parameters at last hit for pion HepSymMatrix m_lerror_k; // error matrix at last hit for pion HepVector m_lhelix_p; // 5 track parameters at last hit for pion HepSymMatrix m_lerror_p; // error matrix at last hit for pion New event model for reconstruction and DST

memory leakage problem Problem description Sources of memory leakage I encountered a. unmathed “new” or “alloc” b. condition skipped c. bad-writtern deconstructors d. problems in event model design Problems unresolved

MdcRecEvent Model: a problem 1.If MdcRecHitCol not registered, Gaudi could not take care of everything 2.If we delete objects,conficts; if not obvious memory leak;

Possible solutions a.Bi-directional relation preserved,using vector(or SmartRef) of object itself b.Only trk->vechits relation maintained, reverse relation with other means( e.g, id), MdcRecHitCol is independent c.MdcRecHit modeled as a common class and no longer using MdcRecHitCol

Present performance  Run smoothly with both Pattern Recognition algorithms  Similar helix results can be obtained compared to 3-D Helix fitting  Material parameters compared to MC: difffences exist, but not substantial  Material effects correction can make the helix parameters better  No obvious efficiency loss

1.0GeV/c Muon, theta=90degree TrkReco+KalFit Entries 998 Mean 1.00 Sigma

1.0GeV/c Muon, theta=90degree TrkReco Entries 998 Mean Sigma

1.0GeV/c Muon, theta=90degree MdcTrkRecon+KalFit Entries 1000 Mean 1.00 Sigma

1.0GeV/c Muon, theta=90degree MdcTrkRecon Entries 1000 Mean Sigma

Some estimations For He/C3H8(60/40), I=43.9eV, from Bethe-Bloch formula, for M.I.P, energy loss is about 1.1keV/cm, for Mdc, L~80cm, dE~90KeV(for small p,L is longer,dE is larger). For Al barrel in MC,d~1mm, 1.615MeV/g/cm2*2.7g/cm3~4.36MeV/cm,so in Al, dE~0.44MeV. For 400MeV/c proton, Beta*gamma~0.43,energy loss ~4 MIP, so totally MIP~0.8MeV. From E-p relation, dP=dE/beta~2MeV For helix fitting, its parameter is something of an average, so the differences of momentum should be half of dP,i.e,~1MeV From the figures below, this argument roughly holds.

0.4GeV/c Proton, theta=90degree TrkReco+KalFit Entries 993 Mean Sigma

0.4GeV/c Proton, theta=90degree TrkReco Entries 993 Mean Sigma

0.4GeV/c Proton, theta=90degree MdcTrkRecon+KalFit Entries 988 Mean Sigma

0.4GeV/c Proton, theta=90degree MdcTrkRecon Entries 988 Mean Sigma

0.4GeV/c Proton, theta=90degree Mean Sigma Mean Sigma

0.4GeV/c Proton, theta=90degree Mean Sigma Mean Sigma Mean Sigma Mean Sigma

0.4GeV/c Proton, theta=90degree Mean Sigma Mean Sigma

Further check More events with broader range of momentum and particle type Using physics event to check Using kinematic fitting to check error matrix thus given Algorithm checking : stereo wires Users are welcome to try it to help improvements