L3 Algorithms: status and plans for the near future All-D  Meeting: 1 st March 2002 Dan Claes and Terry Wyatt.

Design: L1 L2 L3 tape 10kHz 1kHz 20-50Hz Curently: L1 L3 tape. 100Hz 20-50Hz Factor ~ 5 rejection needed Calorimeter-based filtering (jets, electrons, taus) only Next steps (p11.02 release): Improve electron rejection (transverse shower shape) Commission muons and tracking

Level 3 Jargon Tool: Does the real work –Unpacks raw data, finds tracks, clusters –Identifies physics objects (e, , , jet, , W, Z) Filter: Applies (simple) cuts on objects –e.g. pt(  ) > 10 GeV Filter Script: Defines a L3 trigger condition –Logical.AND. of one or more filters –If all filters in a script are.TRUE. trigger is satisfied and event is recorded ‘Mark and Pass’: –Selects unbiassed sample of input events to be recorded –‘Poor man’s’ efficiency calculation/monitoring

L3TJet Tool author: Volker Buescher ( Mainz ) Rejection of L1-accepts makes use of: high precision calorimeter readout available at L3 simple cone algorithm identify (and reject) low-E T events passing L1 trigger sharpen the turn-on curve running online stably since early Sept’01

DATA runs e.g., Fraction of events passing L3FJet(1,15) p T of leading offline JCCA jet (GeV) Main effect smearing turn-on is lack of primary vertex at L3 L3 NADA needed (Marumi Kado investigating) QCD group: currently adjusting each L3 jet p t cut to value at which the relevant L1 trigger reaches ~ 100% efficiency.

L3TEle Electron Tool authors: Volker Buescher ( Mainz ) Ulla Blumenschein ( Mainz ) Current filter: simple 0.4 cone applying cuts on E T emfrac (>0.9) providing a rejection of ~3 PrVtx L3TNullVertex()| CAL_CLUS4L3TCalCluster(calunp=CAL_UNP, vertex=PrVtx, conesize=0.4, MinSeedEt=.5)| ELE_LOOSE L3TEle(CAL=CAL_CLUS4,EMFR=0.9)|

p11 certification: data runs Fraction of events passing L3Fele(1,5) vs p T of leading offline EM object (GeV) after pre- and standard-selections

p11 certification: data runs

Improvements: 1) Reconstruct EM Object within smaller (0.25) cone ELE_LOOSE L3TEle(CAL=CAL_CLUS4, EMFR=0.9 ConeSize=0.25)| L3 Efficiency vs offline EM object pT after pre- and standard-selections Rejection:

Improvements: 2) Additional discrimination available through transverse shower shape cut (shape variables based on an energy-weighted  r) ,  : energy weighted cluster axis position

Z  ee sample data sample  r, floor 1  r, floor 3 ELE_LOOSE L3TEle(CAL=CAL_CLUS4,EMFR=0.9, ConeSize=0.25, Width_EM1=0.085, Width_EM2=0.085, Width_EM3=0.045)|

Events rejected by: p t cut e.m. fraction shower shape

Triggerlist Proposals (single electron triggers): Lower L3 threshold for inclusive unprescaled EM trigger Replace CEM(1,10)L3FEle(1,15,emfr) with CEM(1,10)L3EM(1,12,emfr,cone=0.25,shape) CEM(1,10)L3EM(1,15,emfr,cone=0.25) Replace CEM(2,5)L3EM(1,10,emfr) with CEM(2,5)L3EM(1,12,emfr,cone=0.25,shape) CEM(2,5)L3EM(1,15,emfr,cone=0.25) Replace CEM(1,5)L3EM(1,5,emfr) with CEM(1,5)L3EM(1,7,emfr,cone=0.25,shape) CEM(1,5)L3EM(1,10,emfr,cone=0.25) Rejection =10.3 Drop prescale?

L3FTauHadronic Level3 TauTool author: Yann Coadou (Upsala) non-optimized filter currently in triggerlist, gathering information for tuning under online conditions Running online since 17-Jan-2002 Bug fix to filter installed 09-February p certification included runs over Z  QCD MC data run (>100K events)

Z   + 0 minbias

QCD p T >20 GeV

Raw Data Run , 104k events

Short term goal to filter with L3TMuon cutting on muo_local p T with ‘tight / loose / a-stub’-like quality criteria Mainly needed for single muon triggers (which currently have a L1 prescale of ~25) L3TMuon responsibles: Martin Wegner (Aachen), Martijn Mulders (Fermilab) (and the L3Muon working group)

Test Samples p performance/certification Processed following samples –Single 5 GeV Muon MC,  < events –Single GeV MC,  < events –Golden J/psi samples 300 events –Special run mu1ptaxaa only events –Recent run events No crashes! Rejection factors >4 wrt L1 (loose muons) but p efficiency 50-60% for offline “tight” quality muons Attributed to bugs fixed in p11.02

Muon finding efficiency in p11.02 version Low efficiency for ‘tight’ in central region still under investigation

Most important outstanding issues: 1) Memory leak : approx. 1.5 kB/event (probably in the muon segment reconstruction code) (probably affecting both offline and L3)

Memory leak :

Most important outstanding issues: 2) L3TMuoUnpack (unpacking tool) Current version requires a configuration file. When a module is removed from readout, without a corresponding change to the cfg.dat file, crate data will be ignored creating a hole in L3Muon acceptance A dynamic unpacker independent of rapidly changing configuration files (a fix provided by Scott Snyder) yet to be implemented. However, we hope to run p11.02 muon code online: - initially a test run, in ‘mark and pass’ mode. - aim for active filtering asap!

Recent improvement (p11.02): replace global threshold with individual channel thresholds (as used now in offline reco) Tested on real data >89,000 events (Run FEB) Updating thresholds and cable maps: requires no code changes but care in archiving/version-tagging (general problem!) Daniel Whiteson is studying the improvement this offers global tracking. CFT Unpacking Principal author: Robert Illingworth ( IMPERIAL )

Level 3 Global Track Finding author: Daniel Whiteson ( BERKELEY ) a global (SMT plus CFT) track finder Find axial CFT tracks Match stereo clusters Extend into SMT

Improvement in tracking from new CFT unpacking new unpacking old unpacking Beam-spot corrected dca track phi

Improvement in tracking from new CFT unpacking new unpacking old unpacking Q/ptq/p t Number of smt hits Number of trackschisquared i.e., SMT matching is failing completely!

CFT Tracking Algorithm - L3TCFTTracker Principal author: Ray Beuselink ( IMPERIAL ) P11 tool certification: Robert Illingworth and Chris Barnes CFT unpacked and tracked > assorted MC events (delivered to IC farm by SAM) No crashes, no memory leaks 10,000 events with full (tsim_l3) triggerlist

Tracking will not be perfect for a long time. However, our aim is to try and get tracking turned on reasonably soon. For example, add another electron trigger? CEM(1,10)L3EM(1,12,emfr,cone=0.25,shape) CEM(1,10)L3EM(1,12,emfr,cone=0.25,matched_track) CEM(1,10)L3EM(1,15,emfr,cone=0.25) … and similarly for muons? Or run a standalone track trigger at L3 for single muon triggers? N.B. If you don’t like it, you can always exclude it by using the L3 trigger bits.

L3 Primary Vertex needed soon! author: Guilherme Lima (UERJ/Brazil) Has yet to be tested on REAL DATA Opportunity for new person to get involved! 1) Histogram technique using SMT hits 2) L3TVertexFinder Track-based vertexing tool author: Ray Beuselinck (Imperial) Recently upgraded to use either CFT or Global candidate tracks as input Per Jonsson (Imperial) testing N.B. Marseille group (Arnaud Duperrin, Mossadek Talby, Eric Kajfasz) will be actively involved in testing tracking, vertexing.

Level3 Requirements for certification of Code Fully tested on a Linux system. Works "out of the box" (No private mods to code or RCP files) No crashes/memory leaks on samples of order 100K events: real data and Monte Carlo. Timing studies Performance studies/plots DOCUMENTED Efficiency, rejection, physics distributions these tests may run the tool singly, but : Must run on data with triggerlist exercising all released tools The filter code must be tested, as well as associated tools. Must test persistency of physics_results: Write out events. Read back in to check physics distributions. Verification: run trigger simulator on real data and check that results agree with those obtained online. Shadow nodes (in the future) to test new code ‘online’

L3 Monitoring L3 filter statistics for each trigger available to shift crew via daq_monitor ‘physics_results’ for each tool written out on each accepted event debug_info l3fanalyze program: produces rootuple –Each tool must provide methods to fill rootuple –Used for offline checks of data quality –Plan to run online as ‘examine’ – use root to fill monitoring histograms from rootuple –Extra person needed to work on this! L3 monitoring needs to get a lot more routine!

Conclusions, outlook. Currently factor ~ 5 rejection needed at L3 Calorimeter-based filtering (jets, electrons, taus) only Next steps (p11.02 release): Improve electron rejection (transverse shower shape) Commission muons, tracking, primary vertex Get more systematic monitoring for L3 When L2 turns on we’ll still need factor ~ 5 rejection at L3, but will have to work harder to achieve it!

To find out more: L3 Algorithms web-pages: L3 Algorithms working group meetings take place every on-week, Wednesday 14:00-15:30 in the Farside Talk to Dan Claes or Terry Wyatt about the opportunities to get involved!