L3 Filtering: - short- and medium term plans - how you can help out All-D  Meeting: 14 th March 2003 Terry Wyatt (FNAL-CD/Manchester) on behalf of the L3 Algorithms group.

Functions of L3 filter system Partial event reconstruction Select which events to be recorded Define streams Monitoring For each L1/L2 trigger that fires: One or more L3 scripts run Each script calls the filters/tools necessary for the trigger decision –performed by ScriptRunner –controlled by the trigger list trigger database

Design rates ~2x10 32 L1 L2 L3 tape 5-10kHz 1kHz 50Hz Time budget for L3 filtering  0.2 s per event Current ~2x10 31 L1 L2 L3 tape 1.1kHz 600Hz 50Hz

Currently running online (global_CMT-10.35) cal unpack cal.cluster electron tau jet acoplanarity H t missing E t smt unpack global tracker primary vertex (z) cft unpack muon unpack local muon track-matched muon (+ geometry tool)

Other infrastructure L3 streaming infrastructure essentially ready L3 filter statistics for each trigger available to shift crew via daq_monitor L3 trigger examine –runs on rootuple produced by l3fanalyze L3 physics_results stored on TMB –YOUR physics analysis can become part of routine monitoring of L3!

Using primary vertex z to improve jet E t resolution (Andy Haas)

significantly sharper turn on curve with L3 primary vertex

New Features for p15 gcc compiler primary vertex filter (z) 3D primary vertex finder input run-by-run beam spot p t -dependent track dca errors tools to produce L3 physics_results (start to decouple TMB analysis from L3 algorithm code) needed for impact parameter-based b-tag

Primary vertex filter (Andy Haas) L3 primary vertexing in z –98 % efficient (relative to offline) –Agrees with the offline best vertex –Sigma is 0.36 cm in z Can filter on: –z of the primary vertex –number of tracks in the primary vertex

Possible use –select events within SMT acceptance 25% of events have |Z| > 35cm ~1% of events with >=3 b-tags have |Z| > 35cm bbH MC jet data

3D primary vertex finder (Chris Barnes) Select tracks consistent with: –primary vertex in z –run-by-run beam spot in xy Remove tracks with large  

Run-by-run beam spot vertex_examine BeamSpotMonitor ACNET COOR L3 Supervisor ScriptRunner L3 Tools Michiel Sanders Scott Snyder Gordon Watts Jon Hays L2STT Runs DB same mechanism can be used for other L3 logging/configuration tasks

Beam spot drift from vertex_examine stable over long periods of time position/tilt from previous run/store would usually be good enough precise running strategy still to be worked out 50  m x y (Michiel Sanders)

Impact parameter based b-tag (Per Jonsson)

p15 status Aim to get p15 online within about a month of p15 cut A lot of preparatory work done in test release (Angela Bellavance) –gcc required a large number of packages to be fixed l3fanalyze rootuples produced with t trigsim for data taken online with p13 and global_CMT-10 (Angela Bellavance, Han Do) –performance tests of global_CMT-10 tools underway commissioning the p15 new features may take a little longer

Aims for p16 (June 2003) CPS (Yi Jiang, Andre Turcot) Improve tracking efficiency/resolution (Arizona/I.C.) Extend tracking beyond   1.5 (Arizona) Muons: (Martin Wegner) –track + calorimeter muon id. –di-muon filters Refined treatment of electron shower shape (Ulla Blumenschein) FPD (Tamsin Edwards) FPS ?

Other activities Code management (Angela Bellavance, Jon Hays) On-/Off-line comparator (Han Do) L3 section of MC trigger list (Terry Toole, Terry Wyatt) Identification of physics event types using L3 objects: –J/    (Ike Hall) –Z   (Emily Nurse, Terry Wyatt) routine offline efficiency monitoring online event flagging

Extra help needed urgently! - E.g., Calorimeter tools `orphaned’ electron, tau, jet, missing E t need study of: –primary vertex z to improve E t resolution –calorimeter non-linearity corrections –central track match –influence of L3nada –influence of coarse hadronic layer –other quality cuts? software tools exist need people willing to run Trigsim and look at the resulting rootuple! –recent volunteers: Cristina Galea, Luiz Mundim - E.g., matching L3 objects to MC/L1/L2/reco objects

There are many open questions How to handle redundancy in trigger, e.g., leptons –many L3 filter scripts –one L3 filter script (with details stored in L3 data) Are 256 L3 triggers enough? What else can we do in L3? –more sophisticated monitoring? –technical and/or physics measurements on rejected events? –define “not for reco” stream?

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