Meeting with Bill, Steve, Aous, Riccardo, Eric C, Philippe, Luca, Johan, Leon, Robert Johnson during the collaboration meeting to discuss BT and background rejection
- Effects of BT discrepancies on background rejection:
- Michael et al working on a new release to include pass5 variables into BTRelease; fixing some issues with tagger variables as well; now working on issues from synchornization with GR
- the plan is to check CTBTKR/CAL/GamProbs in the CU and go back to more raw variables in case of differences; prefilter cuts should be first checked; CTBCPFGamProb is not applicable to CU geometry given the few ACD tiles available
- Riccardo is documenting prefilter cuts and relative variable importance for pass5 and will maintain a page for further passes - work in progress
- several people expressed interest for studying a specific subsystem set of variables, which will eventually help shaping a core team of background rejection analyst - more are welcome
- open discussion on which tool should be used to deal with classification analysis, Bill strongly suggest IM, at least for
Some suggestions from Bill and Steve discussed yesterday
- Background rejection variables
- Bill looked at runs 2082 (20GeV e, 0 deg) and 1445 (full-brem gammas) and ran his CT analysis for data and MC; preliminary indications give a small effect on CTBTKRGamProb, a 7% difference on CTBCALGamProb but a negligible effect on the final event classification, i.e. CTBClassLevel; this is encouraging
- Tkr variables
- Bill wants to independetly double-check the beam cleanliness by hand-scanning some events; we discussed on the possibility of providing such a sample set of events along with systemtest or through the pipeline (Tony should be able to run Fred from user requests on specific runs and number of events)
- Energy scale discrepancy
- Bill is reassured by the Geant4-EGS5 comparison, he believe we have a miscalibration somewhere, either in the beamline settings or in the CAL calibration
- Steve is looking into the CAL calibration procedure with help from Sasha and Philippe
- Bill requested an evaluation of the overall uncertainty on the absolute CAL calibration from the uncertainties in the various steps of the calibration
- Philippe will finalize his analysis of calibration factors to be used for i) scaling CAL variables in the data-like simulation ii) use them to recalibrate the LAT CAL if needed