Using L00 Hits

• L00 hits are not added to Production tracks. The proximity L00 to the interaction region results in a high probability of adding wrong hits in high density/ jet like environments. Users should evaluate whether adding L00 hits to tracks is the right thing for their analysis.


• L00 hits can be found and added using the class: L00AddAndRefit.


• Finds L00 hits, adds them to the track and refits the track using the TrackRefitter.


• Detailed documentation may be found in the L00AddAndRefit.hh header


• Usage is essentially the same as the refitter


• Default/suggested search parameters are to use a 100um window and not use hits less than four strips from the next nearest hit(isolation > 175um)


• An example of the use of L00AddAndRefit is given in SiHitAnalyzerModule.
• Look for code activated by the talkto switch AddL00Hits


• L00 also implemented in TrackSelectorModule via tcl switch L00Refit


• Code only works in and with data processed by 5.1.x series releases


• L00 was declared good for physics on June 6th 2002. The first run after that date with silicon on and L00 status good was 147165. Do not use l00 before this date.


• Current best alignment table is:
• 100045 1 GOOD, 150045 1 GOOD, 160045 1 GOOD, 170048 7 TEST, 180048 7 TEST
• Used with 5.x.x series release COT alignment and 5.3.1 Production for dataset 0d
• Five tables are used for these run ranges: before 149717, 149717-158635, 158636 - 168892, 168893 - 179056, and after 179056 respectively. Be sure to use the table that is appropriate for the run range of data you are processing.
• Table description: Based on table 1X0040 1 GOOD with L00 alignments and improved z barrel positions
• You should the calibration pass method to load the these alignment tables.


• Note that it is advisable to use a quality cut when selecting tracks to add L00 hits to. The track should have some hits in SVXII so that the search road to find hits in L00 is reasonably defined. A suggested cut is 3 hits in 3 layers of SVXII


• Be sure to consult the current known problems to check for known L00 problems. Note that there are known and correctable problems in release 5.3.3.