kalfitalg: recent developments and tests

KalFitAlg: recent developments an

d tests

WANG DayongJan.18,2006

Outline

Recent developments and some testsStatus and usagePresent performancesExisting problems and possible solutionsThe 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 -0.002364

Sigma 0.01272

Mean -0.002364

Sigma 0.01272

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 debugWith and without material effectDifferent LR decisionAll hits or used hitsDrift distance and tof correctionComparison of different mass hypothesesComparison of different matrix initializationDifferent cuts for Δχ2

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 2nd 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: Δχ2 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 Δχ2

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 Δχ2=7,9e

mu

pi

K

p

trk

p

K

pi

mu

e

length tof

Filter(forward)

smoother

Psi’’ inclusive Δχ2=7,9e

mu

pi

K

p

trk

p

K

pi

mu

e

length tof

Filter(forward)

smoother

Two track resolution(1)

Helix parameters:1GeV pion

Helix parameters:0.5GeV proton

J/Psirho pi To test the error matrix with the help of kine

matic fitThe algorithm is provided by Kanglin He4C efficiency is lower, so some problem mus

t existCareful check and test is still going on

J/Psirho pi :test

MdcTrkRecon

After KalFit

TrkReco After KalFit

event 1000 1000 1000 1000

2 good trks 459 459 663 663

2 pion 375 375 618 618

>=2 photon 351 351 564 564

VtxFit 350 350 562 563

4C Fit 319 223 483 315

5C Fit 315 222 475 309

J/Psirho pi :test

without wall

Inverse lay dire

Inverse wir direc

Inverse bck-fwd

Inverse lr defin

VtxFit 350 350 350 350 350

4C Fit 219 218 213 221 216

5C Fit 218 218 212 219 215

Matrix gain=1

Matrix gain4000

Diag Matrix

withoutNUMF

No mat effect

VtxFit 350 349 350 350 349

4C Fit 226 223 216 223 212

5C Fit 224 222 215 222 212

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

kalfitalg: recent developments and tests

Documents