GlueX Level-3 Trigger Meeting, Jul 8, 2016
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Contents
Meeting Info.
Meeting Time And Location
13:00 EST (JLab time)
CC F326-327
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Background Information
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Justin's collaboration meeting talks:
Agenda
- Announcements
- Previous Meeting (Jun 24, 2016)
- Benchmarking status (Cristiano)
- Simulation Status (Adesh)
- Resurrecting BDT for simulation (Justin and Adesh)
- Classifying Spring 2016 data (David)
- AOT
Minutes
Attendees: David L. (chair), Cris F., Simon T., Adesh S., Curtis M., Mike W., Justin S.
Announcements
- Meeting time is moved to 13:00 every other Friday to alternate with DIRC meetings
Benchmarking Status
- Cristiano continues to work on benchmarking reconstruction algorithms using janadot
- Looking at real data run 10913 and simulated data from both Adesh's low-threshold data set and the standard "sim1" 3GeV thresh data set
- Previously saw large discrepancy between real and simulated data but is now seeing better agreement due to:
- Newer software (unsure if this was important factor)
- Better job skimming only physics events
- MC data has more tracks/showers per event than real data
- Currently the simulated data does not have a L1 trigger emulation applied
- Alex S. is working on a L1 trigger emulator using configuration info. recorded in RCDB
- Justin suggested turning off all but pion mass hypothesis for tracking. That will make it faster and we are unlikely to need multiple mass hypotheses to make L3 decision
- Mike suggested we could improve tracking speed for L3 decisions if we dropped tracks that look to be low momentum early on (this was done in LHCb to significant benefit)
- Cris will look at comparing DTrackCandidate results to DTrackTimeBased since the candidate momentum would be the natural place to make this cut
Simulation Status
- Simulated data set is now available
- Noticed MIP peak in FCAL has more energy for real data that for MC
- Justin noted that there may be a trigger bias with the real data
- This can be investigated by looking at events where the trigger condition is met by a different part of the detector
Resurrecting BDT for simulation
- Justin found old code from few years ago when initial L3 BDT studies were done and applied it to data simulated with Spring 2016 conditions
- Performance was similar to what was seen 2 years ago
- L3 trigger efficiency at 20kHz is ~93.5%
- For 99% L3 trigger efficiency, we'll reject about 50-60% of background with the present scheme
Classifying Spring 2016 data
- David showed some results from trying to categorize events as "good" or "bad" from 2 runs from the Spring 2016 data set
- run 11667=1345A and run 11511=1200A
- Approximately 1/4 of the physics events satisfied the "good" condition of >4GeV reconstructable energy in the event
- Following up on a suggestion from Eugene, some attempt was also made to identify what fraction of L1 events were due to a small number of clusters near the beamline in the FCAL
- These would be characteristic of EM events which are of less interest
- An estimated 10% of L1 events met this condition
- Excluding first 2 rings of FCAL blocks from trigger seems to have effectively suppressed many of the EM events
- The "good" classification was used to train a BDT using lower-level event information as variables
- Retaining ~99% of events would lead to rejecting ~35% of background
- Higher level reconstruction variables will be added to see how this might be improved