KalFitAlg: recent developments and tests WANG Dayong Jan.18,2006

Outline  Recent developments and some tests  Status and usage  Present performances  Existing problems and possible solutions  The next to do

A retrospect: what we achieved for Boss5.0.0(Nov,2005)  Event model in both TDS and DST are fixed, root file persistified, the loop closed for KalTrack  Previous memory leakage problem extensively inspected and cured by a new model with improved track-hit relation after discussion  Check and use nearly the same material and geometry parameters with simulation  Run smoothly with both Pattern Recognition algs and nearly the same or a little better helix parameters and momentum as PR algs obtained, the tendency of error matrix variation is correct with 5 particle hypotheses.

0.4GeV/c Proton, theta=90degree Mean Sigma Mean Sigma From wangdy’s report at software meeting Nov.3

Recent developments since Dec  Backward fitting with different mass hypotheses  Flight length and TOF calculation  Sampling length calculation  Extraction of control flags and parameters  Codes adjustment and comment to make it more clear a  Many checks and tests for multiple scattering, energy loss treatment, inner wall treatment, choices for cuts, etc (see the following)

Tests and debug  With and without material effect  Different LR decision  All hits or used hits  Drift distance and tof correction  Comparison of different mass hypotheses  Comparison of different matrix initialization  Different cuts for Δχ 2

Status and usage  Helix and error matrix at IP: 5 particle hyp. directly for physics analysis  Helix and error matrix at MDC innermost layer: 5 particle hyp. for 2 nd vertex fitting  Helix and error matrix at MDC outermost layer: 5 particle hyp. (optional), for track extrapolation  Flight length from IP to outermost layer and time of flight: different particle hyp. optional, for TOF recon.  Sampling length at each layer: for dE/dx recon

Control flags and parameters muls: multiple scattering 0:close 1: open loss: energy loss 0:close 1:open lr : how to set lr ambig 0:independendtly 1:use lr from PR matrixg: the factor to use in matrix initialization debug: debug verbose 0:close 1--4: lower to maximum ntuple: control of ntuple using bitmap FEDCBA A:n101 B:n103 C:n102/n104 D:n105 E:mctruth in n101 F:error matrix activeonly: whether use active hits only 0:all 1:active hits only matfile, cylfile: dir and name of data file currently used deltachi2_cutf, deltachi2_cutfs: Δχ 2 cuts pe_cut, pmu_cut, ppi_cut, pk_cut, pp_cut: mom cut in filter back :backward fitting 0:close 1:open i_back: mass hyp. used in backward fitting <0 :only pion Pt: pt cut for backward fitting tofflag : re-calculate the drift distance with tof correction tof_hyp: mass hypothesis when calculate TOF

Choice of cuts for Δχ 2  One cut is not good enough, so we set two, different for forward and backward fitting  The criteria is the distribution of chisq and probability  The cut is tested with kk2f, dimu, and different tester samples  At present, the cut is set as 7.0 and 9.0 respectively, still need optimization

1GeV/c Pion Δχ 2 =7,9 e mu pi K p trk p K pi mu e length tof Filter(forward) smoother

Psi’’ inclusive Δχ 2 =7,9 e mu pi K p trk p K pi mu e length tof Filter(forward) smoother

Two track resolution(1)

Two track resolution(2)

Two track resolution(3)

Helix parameters:1GeV pion

Helix parameters:0.5GeV proton

J/Psi  rho pi  To test the error matrix with the help of kinematic fit  The algorithm is provided by Kanglin He  4C efficiency is lower, so some problem must exist  Careful check and test is still going on

J/Psi  rho pi :test MdcTrkR econ After KalFit TrkRecoAfter KalFit event good trks pion >=2 photon VtxFit C Fit C Fit

J/Psi  rho pi :test without wall Inverse lay dire Inverse wir direc Inverse bck-fwd Inverse lr defin VtxFit350 4C Fit C Fit Matrix gain=1 Matrix gain4000 Diag Matrix without NUMF No mat effect VtxFit C Fit C Fit

Possiblities Multiple hits in a single layer Sign conventions Others???

Other issues  Non Uniform Magnetic Field:  Wire sagita: the framework for this is there; c++ implementation of the correction function by Jike Wang  Wire shift, x-t relation, wire resolution: from calibration

The next to do  Find out the origin of the problem rho pi and improve  Optimization of all the parameters and cuts with different physics events  More error matrix check with other physics channels  Documentation and notes