LHCb Lausanne Workshop, 21st March /8 Tracking Open Issues E. Rodrigues, NIKHEF LHCb Tracking and Alignment Workshop Some topics to discuss …

LHCb Lausanne Workshop, 21st March /8 Tracks Locations in TES At present: /Event/Rec/Track/Ideal /Event/Rec/Track/Seed /Event/Rec/Track/Velo /Event/Rec/Track/Forward /Event/Rec/Track/VeloTT/Event/Rec/Track/Match/Event/Rec/Track/KsTrack/Event/Rec/Track/Best But not enough … agree on following off-/on-line? /Event/Rec/Track/Ideal /Event/Rec/Track/Seed /Event/Hlt/Track/Seed /Event/Hlt/Track/RZVelo /Event/Hlt/Track/RZVelo /Event/Rec/Track/Velo /Event/Hlt/Track/Velo /Event/Rec/Track/Forward /Event/Hlt/Track/Forward /Event/Rec/Track/VeloTT /Event/Hlt/Track/VeloTT /Event/Rec/Track/Match /Event/Rec/Track/KsTrack /Event/Hlt/Track/KsTrack /Event/Rec/Track/Best /Event/Hlt/Track/Best Some locations not needed online/offline

LHCb Lausanne Workshop, 21st March /8 2 Packages available:  PatChecker, TrackCheckers For sure a lot of double work:  Could easily share tools and code  Should be merged as much as possible, or even completely? Do we have all we need for checking?  Tools needed  Relations/linker tables  In.digi and.dst files Checking Packages

LHCb Lausanne Workshop, 21st March /8 Tuning of Pattern Recognition Versions for online:  Default options for PatVelo, PatForward are for HLT, I believe  Re-tuning for DC’06 is ongoing Versions to be used offline:  Use same VELO and forward tracking as online, but with different tuning  No such tuning yet available  What is the timescale for having an offline tuning?

LHCb Lausanne Workshop, 21st March /8 Track filters:  Alignment developpers have already raised the question of how to easily get e.g. a long track with only VELO / seed hits (LHCbIDs)  Seems like a “stripping” tool could be handy …  We have already some very simple track selector tool, but  Actually one could make a set of filter tools similar to the FilterCriterion family of tools of DaVinci! Clone killer and “tracks cleaner” before DST writer:  Clone killer algorithm provides “best” set of tracks for physics  These tracks still have too much info that is not to be stored on DST  Need a procedure to clean these tracks: all but first state, all measurements, etc.  Have to see relation to old “PackXxx” algorithms … Non-const accessors :  Can we please make sure we have a clear idea of the problem, the possible solutions and the pros and cons? With some quantitative timing justifications … Miscellaneous

LHCb Lausanne Workshop, 21st March /8 Fitting and OT Ambiguities Outcome of the event model review Most people wanted a very simple LHCbID  Means no more “spare bits”, where OT ambiguities could be stored LHCbID simplified  Contains simply some bits for the detector type and the bits for the XxxChannelIDs  Bye-bye OT ambiguity … Issues OT ambiguities only available in the pattern recognition algorithms  How to pass that info on to the fitting? Seems impossible now … Can we do (fit) without the OT ambiguities?  Not clear. Nobody really knows … will be investigated with DC’06 … The problem in 1 sentence: How to fit without OT ambiguities?

LHCb Lausanne Workshop, 21st March /8 One possible solution Build the Measurements inside the PR algorithms  Probably OK for offline tracking  Easy recipe “on demand”. E.g.: Henk Jan has in hands a few lines to do this …  could even introduce a new algorithm property “MakeMeasurements” …  I would propose this solution offline What about online?  Information lost if the Measurements are not built in the “Pat” packages …  … unless we make e.g. some linker-like table à la MCTrackInfo/whatever … or... Otherwise … Need to know the impact of not having the ambiguities at the start of the fitting  Are we stuck?  Any brilliant ideas / alternatives? The contest is open … Fitting and OT Ambiguities

LHCb Lausanne Workshop, 21st March /8 Bottom line … Having a robust / flexible / beautiful tracking is not yet a realityHaving a robust / flexible / beautiful tracking is not yet a reality Many issues have to and will be addressed during our DC’06Many issues have to and will be addressed during our DC’06 Looking forward to the real challenge – DATA!Looking forward to the real challenge – DATA! Disclaimer: apologies for the issues I’ve probably forgotten to state …Disclaimer: apologies for the issues I’ve probably forgotten to state …