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Offline Status Report

Offline Status Report. M. Moulson, 20 December 2001 Summary presentation for KLOE General Meeting. Outline: Processing of 2001 data History of datarec executable DST production and reprocessing: Status and plans DC tracking: current problems. Processing of year 2001 data.

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Offline Status Report

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  1. Offline Status Report M. Moulson, 20 December 2001 Summary presentation for KLOE General Meeting • Outline: • Processing of 2001 data • History of datarec executable • DST production and reprocessing: Status and plans • DC tracking: current problems

  2. Processing of year 2001 data Integrated luminosity (pb-1) Run Luminosity (weekly avg., mb-1/s) Day of year • Reference data set: • Runs 17689—23141 (17 Feb—9 Dec) • 18.1G triggers, 52825 files, 49 TB raw data • Reconstructible Ldt • 175.4 pb-1 • Total events collected: • 932M Bhabhas • 540M f decays • est. sf = 3.1 mb • 80M KL tags • 59M KL crash • 132M K+K- w/ vertex • 45M rp tags

  3. 2001 data: acquisition statistics Low background, L Events per mb-1 Acquisition rate (KHz) 8 9 10 11 2001 date 2001 date Sept. startup • Apparent decrease with time mostly an effect of increased L • Implies absolute background levels constant over long term (compare RDAQ) • On surface, RDAQ stable with respect to L • In reality, some dependence on L within run groups

  4. 2001 data: processing statistics Low background Sun IBM 8 9 10 11 2001 date 2001 date eFILFO 36% Fraction of events tracked CPU time per trigger (ms) • Significant effect on CPU from use of IBM’s • Variations in fraction tracked also important • Sept-Dec period: ~21 ms/trig • L only partially explains variations • fNov-Dec 0.5  eFILFO  36% • eFILFO can be evaluated knowing L, Rtrig and shows same structure

  5. 2001 data: output statistics 8 8 9 9 10 10 11 11 ksl event size (KB) Events/mb-1 in ksl stream 2001 date 2001 date • Effect of compression (DBV-10) clear • Event size otherwise stable • Not obvious, large bkg component? • Exact same trend seen in events/mb-1 • Implies significant constant bkg in ksl • sksl expected ~1 mb, Nov-Dec: 1.7 mb

  6. 2001 data sets and datarec versions Streaming ~10% of total events (half of which Bhabhas) Size of datarec output  size of raw data Size of physics events  half size of datarec output 97% of good luminosity processed

  7. Reconstruction issues

  8. Reprocessing plans • Total CPU bandwidth: 2670 Hz • 56 IBM CPU’s available, 21 ms/trigger • Total bandwidth to/from tape: 5000 Hz • Data rate in DST pass: 4.5 MB/sec per drive • Average input event size: 2.7 KB • Input/output volumes approximately equal: assume 3 drives • Mean event processing rate: 1740 Hz • New kpm selection algorithms imply complete reprocessing from raw • Use this opportunity to remedy all known problems with earlier reconstructions • Complete reconstruction will take ~4 months • Start date: 10 Jan 2002 • Finish date: earlier of • 10 May 2002 • New data in earnest

  9. DST specifications • Compressed YBOS format • Contain subset of banks and event tags essential to analysis • Raw banks dropped after initial period of debugging • Produced from datarec output (at least initially) • Separate jobs for kpm, ksl, rpi, rad streams • One output DST per run and stream • Exception: rad stream (separate charged and neutral DST’s) • Fully integrated into run database • DST files accessed via KID, show up in list_datarecs, etc. • NFS-mounted recall areas for analysis • Substantial fraction of DST output available on disk at any given time

  10. DST bank list

  11. DST details: ksl stream • KSTAG rejection to reduce stream volume • Complete calorimeter reconstruction (including TCA) • Update calibrations (not needed for DBV-11) • Preferable anyway avoid problems in setting global T0 • Tracking: Bhabha overlaps not a problem • Events tracked as Bhabhas are essentially Bhabhas • T0 step 1 redone for KLTAG’s with TRF = 5.4 ns • Diagnostic histograms filled, DB2 updated • SELCOS, SPLASHFILT recovery (DBV < 11) • Raw data processed with DBV-10 filters negated

  12. DST details: rad stream • Two output DST’s: drn (NRFILT) • drc (PPFILT, PPGTAG) • Tracking: 60% of rad events have DTFS for Bhabhas • Hit addition, multiple scattering, kink finder disabled • These events completely retracked • Complete calorimeter reconstruction (including TCA) • T0 step 1 redone for NRFILT events using dedicated algorithm • Diagnostic histograms filled, DB2 updated • NRFILT, SELCOS, SPLASHFILT recovery for DBV < 11 • Raw data processed with DBV-10 filters negated • NRFILT has interface with FILFO, recovery from raw

  13. DST status • ksl stream: dk0 • DBV-11 (60 pb-1) completed 10-18 December • Processing speed: 0.9 pb-1/hour • 7 IBM+11 Sun CPU’s, 4 drives (14 MB/sec total) • Approximate output size: 3 MB/nb-1 • Excludes raw banks • 600 GB for all 200 pb-1 • Raw banks retained first few pb-1 and double output size • rad stream: drn, drc • DBV-11 completed (?) 18 December to today • Processing speed: 1.2 pb-1/hour • Fewer input events, more CPU/event due to tracking • Approximate output size: 3.8 MB/nb-1, including raw • Raw banks retained first 9 pb-1

  14. Plans for DST production • DBV-11: 60 pb-1 • Produce DST’s for rpi stream: d3p, very similar to drc • DBV-10: 82 pb-1 • Produce DST’s for ksl, rad, rpi streams • More complicated because of need to recover events from raw • DBV-8 & DBV-9: 29 pb-1 • Wait for general reprocessing • Ready to begin DST production à la DBV-10 if reprocessing delayed beyond 10 Jan 2002 • DST’s currently archived on tape • Request NFS-mounted dedicated recall areas to be ready by mid-Jan 2002

  15. Electrons Positrons Hits/track f (rad) f (rad) DC tracking: hit inefficiencies Number of hits assigned to tracks in Bhabha events shows dropouts every 30 in track azimuth (f) Effect has been present from the very beginning

  16. Hit inefficiency diagnostics Lost hits are actually rejected by hit-rejection algorithm e tracks in Bhabha events affected in both MC and data pfrom KS p+p- not affected (neither MC nor data) Rejected hits, y vs. x (cm) Bhabha (data) Bhabha (MC) KS p+p- (data)

  17. Hit rejection and the L/R ambiguity Rejected hits, Bhabha events Example Bhabha event (MC) Incorrect L/R causes hits to be dropped on many consecutive layers Rejected due to incorrect L/R resolutions y (cm) Drift Distance, Recom (cm) Normally rejected on basis of residuals x (cm) Drift Distance, MC (cm) • Periodic effect in f presumably due to alignment of wires • Bhabha tracks monochromatic, small curvature: correlation between f and wire crossing points • Effect not present in MC when correct hit lists and L/R resolutions used

  18. Bhabha hit inefficiencies and luminosity • Effect on luminosity estimate expected to be negligible: • No evidence of modulation in f of Bhabha tracking efficiency • Bhabha tracking efficiency 99.9% for 50 < q < 130 • Some concern about accuracy of track parameters (z?) • Effect is present in MC, and therefore taken into account dp(Recon-MC) (MeV) f (rad)

  19. Bhabha hit inefficiency: solutions • Improvement of PR algorithm • “New” algorithm for estimation of track parameters allows L/R assignments to be redetermined • Under test • Improvement of hit-flipping algorithm in track-fit code • Cannot correct L/R when many hits need flipping simultaneously • Add capacity to look at global solutions

  20. Conclusions • 175 pb-1 of 2001 data processed to 97% completion • DBV-11 DST’s (60 pb-1) essentially ready • Can produce DST’s for each stream at ~1 pb-1/hour • DBV-12 reconstruction to start 10 Jan 2002 • Resolution of L/R ambiguity in PR/TF under study

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