This page is out of date. See StRoot/StEvent/StTrack.h for the correct definitions.

The dst_track.iflag definitions

MOST IMPORTANT POINT iflag>0 GOOD iflag<0 BAD

iflag=xyy, where x indicates the detectors included in the fit and yy indicates the status of the fit. Positive iflag values are good fits, negative values are bad fits.
 

The first digit indicates which detectors were used in the refit:
x=1 -> TPC only
x=2 -> SVT only
x=3 -> TPC + primary vertex
x=4 -> SVT + primary vertex
x=5 -> SVT+TPC
x=6 -> SVT+TPC+primary vertex
x=7 -> FTPC only
x=8 -> FTPC+primary

         

If a refit is performed by egr then the last two digits are as follows
 

The last two digits indicate the status of the refit:
= +x01 -> good track
= -x01 -> Bad fit, outlier removal eliminated too many points
= -x02 -> Bad fit, not enough points to fit
= -x03 -> Bad fit, too many fit iterations
= -x04 -> Bad Fit, too many outlier removal iterations
= -x06 -> Bad fit, outlier could not be identified
= -x10 -> Bad fit, not enough points to start

If no refit is performed by egr then the flag is defined as follows:

 TPC only tracks
 
      iflag = (sign(1.0,float(tpc_track.flag)))*100+tpc_track.flag

      where
 

= -x01 -> Bad fit, outlier removal eliminated too many points
= -x02 -> Bad fit, not enough points to fit
= -x03 -> Bad fit, too many fit iterations
= -x04 -> Bad Fit, too many outlier removal iterations
= -x06 -> Bad fit, outlier could not be identified

          = -x10 -> Bad fit, not enough points to start

       and a good track has
           yy = ipass+10*int(what+1.0)

           ipass indicated which pass through the TPC tracking the track was identified on and what
identifies which pass through the segment formation routines the track was formed
 

  SVT only tracks

     iflag = (sign(1.0,float( svt_track.flag)))*200.+svt_track.flag

      where svt_track.flag = 1 good fit from primary track fit
                                        = 2 good fit from secondary track fit
                                        = 0 bad track

  Matched SVT and TPC tracks

      iflag = svt_track.flag*10+(sign(1.0,float(tpc_track.flag)))*500+tpc_track.flag

  FTPC only tracks

      iflag = x01 -> good primary track
              = x02 -> good v0 track

 In all cases

   if abs(icharge) .ne. 1          iflag = -1*(iflag+20)

   if abs(invpt) .ge. 999999 iflag = -x99

Some of this is under reconsideration. Do not take it on face value, Spiros

These flags are carried into StEvent in the  StTrackFitTraits mQualityBitmask = iflag

Contact Person: Helen Caines