Offline Status Report

1. Offline Status Report M. Moulson, 27 Feb 2001 Summary presentation for KLOE General Meeting • Outline: • Processing of 2000 data • Upcoming developments for datarec executable • Status of MC production • Ntuples/DST’s: status and proposals

2. Processing of fall 2000 data • Reference data set: • Runs 15197—17330 (23 Sep—11 Dec) • 5.61G triggers, 15543 files, 13.6 TB raw data • Offline Ldt = 23.1 pb-1 • DBV-6: 5.5 pb-1 • DBV-7: 18.0 pb-1 • Total events collected: • 130M Bhabhas • 67M f decays • est. sf = 2.9 mb • 10.9M KL tags • 7.2M KL crash • 19.5M K+K- w/ vertex • 6.2M rp tags

3. Processing statistics for fall 2000 data Avg. time/tracked evt. Avg. time/trigger 38 ms 151 ms Avg. fraction of events tracked: 26% Raw data: 5605M Events, 13.6 TB Physics: 2.0% of total events 25% of raw volume 160 GB/pb-1 Bhabhas: 2.3% of total events 20% of raw volume 114 GB/pb-1 Avg. bandwidth on 40 CPU’s: 1060 Hz

4. datarec performance in fall 2000 Evts. acquired Evts. processed Acquistion rate Farm bandwidth Reconstruction rate No DC trig End of data Follow-up After Xmas Missed runs Reprocessing 11 Dec 23 Sep Daily averages • Average uptime efficiency: 63% • Staging and procedural losses count Once in stable situation, able to follow with ~75% of data processed

5. Data processing: Issues to discuss • Streaming-related issues: • flt stream (raw) • About 30% of raw volume (3.8 TB in 2000) • Apparently never used • selcos cosmics • 10% written as raw, also processed • Increase statistics in raw, don’t process • Increase number processed, don’t write raw? • Reprocess runs processed before final EmC calibrations available? • Currently we do not wait for calibrations before reconstructing • Complete EmC reconstruction is performed before Ntuple/DST production • Ntuples/DST’s, YBOS out of phase • Effects on streaming are permanent • Intended to give feeling • Not an exhaustive list • More detail at review • Reprocess DBV-6 (5.5 pb-1) for neutral radiatives? • FILFO Bhabha filter deleterious • Rejects 40% of f  hg  ggg events • Only runs on “charged” events • Pre DBV-7: Charged event: Nhits > 30 • Pileup contribution to Nhits in 2000 data • DBV-7: Bhabha filter vetoed by neutral radiative tag instead of Nhits cut • Luminosity to 1% only possible with DBV-7 reconstruction

6. Next version of datarec executable • Already in DBV-8: • CLUFIXENE MC events, scale factor • EMCALIB slewing corrections • VTXFIN corrected path length calculation • TRCLMOD modified projection from track to cluster • Ready for inclusion in datarec: • FILFO fast tracking cuts, Nhits definition • VLAB new luminosity module • A_C zlib event compression

7. CLUFIXENE MC: f  f0g  5g events Before scale corr. After scale corr. • How it works: • loop over “missing” cells • attenuation length correction from zcl • sum EA and/or EB into cluster • fscale because ABSCAL done w/o CLUFIXENE • Problems: • CWRK not updated for missing cells • Ecorr  Ecl – Eclbef not saved in bank stream • Makes fscale necessary • ABSCAL uses CWRK • New developments: • CLUFIXENE now works for MC events • fscale off by 2%—adjusted • In progress: • Bookkeeping mechanism to replace CWRK • CSPS bank includes missing cells • ABSCAL will run on CSPS • Remove scale factor

8. EMCALIB: Slewing corrections T5 T1 v12 Slewing correction now applied cell-by-cell e+e-g evts. w/w/o slewing correction • TcorrA,B = TA,B – T0A,B – TslewA,B • TslewA,B = Const/(EA,B)0.1 • Empirical prescription, same for all cells • Tested on “old” data with T0’s adjusted by hand • Correction now applied in T0ALIG and TIMCAL • Disabled in code for runs < 17606 • Diagnostics: • T1-T5 distributions OK • v12 distributions OK • FILFO should not be affected

9. CLUREC: New clustering cuts Clusters are merged if: Dr  40 cm All four conditions must be met Dr  20 cm Dz  30 cm Dt  2.5 ns Attempt to tune CLUREC cuts to minimize cluster splitting • Most split clusters are actually unmerged clusters • Basic problems: • Current cuts do not depend on Ecl • Complications from shower fragments • Problem of unmerged clusters has been comprehensively studied Proposed new merging criteria: • Status: • Performance gains to be evaluated • Implementation easy

10. Cluster efficiency studies g1 p+ p0 p- MC Data 1.2 g2 1.0 0.8 100 200 300 MeV • From e+e-g events: • Good vertex, 2 tracks, high p • p1, p2 > 490 MeV • Exclusion region around e± clusters • pmiss(DC) gives direction of expected g • Systematic from cone definition • Studied in data, MC • From fp+p-p0 events: • Good vertex, 2 tracks • pmiss(DC) = pp0 • g1 direction gives expected E1 • Compatible g1 identified direction of g2 • Systematic from cone definition • Advantages: • higher pmiss(DC) • smaller systematic with qg, Eg e+ g e-

11. Cluster efficiency: Data and MC eg from e+e-g evts. with thresh. simulation MC Data MC Data Tail normalized Ecell (MeV) • Simulation of cell thresholds • MC: • Only when no p.e. after attenuation simulated at one side • Relatively hard cutoff at ~2 MeV • Real life: • Roll-off, characteristic value ~7 MeV • Compare MC to data using e+e-g events • Erec for all cells associated to clusters • on barrel, Ecl > 200 MeV • similar shape on endcaps • A_C module EMCFAKETHR: • Deletes CELE hits from MC events according to hit-or-miss sampling of Rcell • Brings eg(Eg) for data and MC into agreement for high qg • Some systematics to be studied: • +1 MeV offset in ErecMC to obtain good results • Ultimately hope to avoid having to map Egmethod to EgKINE when applying corrections • Status: almost ready for release

12. EmC data structures • CTRG: Sector  cluster correspondence bank • Combines information from PZZA, TELE banks • Number/kind of sectors not connected to clusters • For all clusters: indices/kind of sectors incorporated • Can also obtain indices of clusters in each sector • Status: done, also in PROD2NTU • CSPS: Calorimeter space-point bank • Combines information from • CELE: EA, EB, TA, TB • CWRK: (E, X, Y, Z, T)cell • into one compact structure, capable of storing multiple hits per cell • Status: development, almost ready • CLUS: Compact cluster bank • Analogous to CSPS • Status: ideation

13. FILFO: Cuts and DC noise Nhits 0 t measured estimated • FILFO cuts on number of DC hits (Nhits) • Cosmic rejection: • By crossing speed, shower depth cuts for Nhits < 175 • By ring cuts for 0 < Nhits < 60 • Cosmics discriminated from K+K- events by Nhits < 100 under certain conditions • MB rejection: • MB events have Nhits < 200 • Min EmC energy vs. Nclust for neutral events (Nhits < 50) • Noise hits in DC create interference • Hot channels masked in RAW2DTCE • Problem from diffuse component of noise • Does not depend on detector • Can be estimated from Nhits(t < 0) • Nhits(adjusted) = Nhits(raw) – Nfake • Status: • RAW2DTCE already modified • FILFO modification trivial • Gains under study

14. FILFO: Fast tracking RAW EmC reconstruction t0 step zero FILFO Mach. Bkg. Cosmics ATFMOD/VTXFIN par = 4 FILFOTRK Single track events ATFMOD/VTXFIN par = 1 ATFMOD/VTXFIN par = 3 Event Classification UFO’s xxx .bha Physics streams Bhabha stream • Modifications to ATFMOD • Added parameter suppresses: • Hit addition/rejection • Kink finding • Multiple scattering • Number of iterations during refitting • Similar procedure used for Bhabhas • Reduces reconstruction time 4—5 • New module: FILFOTRK • Rejection based on preliminary tracks • Currently implemented: • Single track events • Eventually: • Inclusive cuts based on • event selection algorithms • Status: • Code structure complete • Gains fully realized with new rejection criteria • Possible to jump-start tracking?

15. VTXFIN: Path length calculation 1 Relative to analytic (helix) calculation: Should have some tails 20 cm DC BP 2 OK • Errors fixed in calculation of track length from FH/LH to vertex • Vertex position not affected • Stepping error (1) • Avg. effect: -2.5 cm (modularity: 5 cm) • Numerical extrapolation of track • Uses B, takes into account dE/dx • 5 cm step size (except last step) • For L, vertex was put at beginning/end of step because calculation was incorrectly started from FH  LH • Endpoint error (2) • Avg. effect: +20 cm • Vertices b/t BP and DC • Tracks which intersect BP • Both fixed in DBV-7 • Function vtxswm_p2n • Analytic calculation of L • Works with PROD2NTU

16. TRCLMOD: Recent developments NEW EmC OLD • 1.Track length from LH to EmC systematically overestimated by 2cm • Pre DBV-8: Can simply subtract 2 cm from this length • Often canceled with –2.5 cm error in VTXFIN track length (hard to detect!) 3. Talk-to option to force TCA for tracks that end at vertex 2. Changes in calculation of association c2 • Old cuts: • Df, Dz (barrel) • Dx, Dy (ecaps) • New cut: • Distance TCA usually inhibited— idea is to follow “tree” May recover cases involving split tracks Cuts are large—does not have a large effect except for case of large angle of incidence • Not default behavior • Contemplate use in KS semileptonic analysis in order to get better control over TCA efficiency

17. Luminosity measurement in 2000 3dim - Accolinearity 3dim - Accolinearity New Version of BABAYAGA ! 1% cos  > -0.975 • Traditional offline L estimate from LAB’s: • 2 clusters with 45° < q < 135° • 300 < E < 600 MeV • Acollinearity in q < 10° • In time within 4 ns • Acollinearity in f < 80° • Problems: • gg separation: 50 hits in DC • Up to 8% background from gg’s • esp. at beginning of 2000 running • Emax cut unstable w.r.t. energy calibration • s(E) = 42 MeV at E = 510 MeV • 3% effect • On-the-fly fixes in 2000: • Exclusive 3D acollinearity cut to eliminate gg’s • Emax 600  800 MeV

18. VLAB luminosity measurement E + - GEANFI BABAYAGA Data  Q + - • Starting sample: FILFO LAB’s • with 2000 cut revisions • Event selection: • 2 tracks from IP with opposite charge • rxy < 7.5 cm, rz < 15 cm • Distance between 1st hits > 50 cm • VLAB cuts: • 55° < q(cl) < 125° • Acollinearity in q < 9° • 400 MeV < E(tr) < 600 MeV • MC effective cross section = 421 nb • 0.3% background from p+p-g events manually subtracted • New L estimate from gg events (GGL) • FILFO LAB cuts • Cut on Nhits vs. 3D acollinearity • MC effective cross section = 118 nb

19. VLAB status VLAB routine is well tested and performs as expected • estimated systematic effects from cuts on E, q: dL/L < 2% • best-tested and most accurate luminosity measurement yet VLAB has been implemented in an Analysis Control module • all relevant parameters accessible via Talk_To • will be inserted in next datarec version • long term method test by comparison to Gold Bhabhas, LAB’s, and GGL Number of VLAB candidates to be written to DB on a file-by-file basis • statistical accuracy for a single run: 30 nb-1 dL/L= 0.9 % Plan to process DBV-7 bha stream to produce luminosity map (17 pb-1) • Pre DBV-7 executable had Emax(cl) = 600 MeV cut  LAB sample biased

20. New version of GEANFI • GEANFI version 1.06/07 released on 6 February: • EVA generator inserted • p+p-g generator with different models for ISR, FSR, interference with f0g • w  hg decay inserted • h  3g decay (C-violating) inserted • Improved simulation of K 3p decays • f  rp+3p generator • added parameter to specify fraction of decays that don’t proceed via rp • Modifications to GEANT tracking to allow generation of specific KL topologies • KL decays in beam pipe • before entering DC • before entering calorimeter • in calorimeter • Change name of output banks: DTCE  MDTC, CELE  MCEL • Makes it easier to re-reconstruct MC files that have already been reconstructed • New default value for magnetic field: I = 2300 A

21. Modified MC banks and analysis chain mco MCEL MDTC RAW2CELE/ RAW2DTCE CELE DTCE TSKT/ SMEAR_T0 Smeared banks EMCALIB/CLUREC/ CLUFIXENE MCEL, MDTC T0_FIND/CLUFIXTIM/ T0_MENO Corrected banks All other reconstruction mcr raw • New names for MC output banks: • CELE  MCEL, DTCE  MDTC • Pristine banks for re-reconstruction • New A_C path for MC reconstruction: • use (dmapload) emcdbini raw2cele dcdbini raw2dtce (tskt smear_t0) emcalib clurec clufixene t0_find clufixtim t0_meno filfo dconvr… • For MC versions 167 and later • Re-reconstruction w/w/o redoing trigger simulation/t0-smearing OK • For MC versions pre-167: • Original trigger simulation/smearing automatically used • Re-reconstruction w/ new trigger simulation/t0 smearing not possible • New routine to obtain MC version • GET_MC_VERSION(VERSION) CALR DCHR RAW2CELE/ RAW2DTCE CELE DTCE EMCALIB/CLUREC/ CLUFIXENE CALR, DCHR T0_FIND/CLUFIXTIM/ T0_MENO Corrected banks All other reconstruction xxx Data MC

22. Status of MC production • Production details: • New GEANFI version (1.06/07) • New datarec version (DBV-8) • 8 offline nodes (fsun03-10) • Environment similar to datarec • Output: • Reconstructed YBOS files (.mcr) archived to tape • Program: • Continue with MC production until farm bandwidth needed to reconstruct new data • 9 days at current rate MC production for 2000 data started 9 Feb

23. Ntuple production for ksl stream • Starts from ksl stream • EmC reconstruction • t0 find (step 1) • PROD2NTU ksl Ntuples • ksl Ntuples split into substreams • YBOS output for KL  2p0 events • manual tape backup • Status: • About 4 pb-1 processed in Jan • 23 GB of Ntuples! • Eliminated KS tag • Dropped DPRS block • TELE, PIZZA blocks condensed into C2TRG • Restarted 19 Feb, immediately stopped • Initially for machine problems • Fine-tuning of scripts, output file sizes • 30-50% reduction in data volume • Restarted this weekend, 1 pb-1 processed

24. DST production for radiative stream • Starts from rad stream • EmC reconstruction • t0 find (step 1 radiative) • Retracking for p+p-g events that overlap with bha stream • YBOS DST’s: • 4 substreams for analyses in progress • Subset of events in rad stream • E.g., e+e-g, gg events • Reduced bank set • Manual tape backup • Diagnostic Ntuples for some substreams • Diagnostic Ntuples: • Allow estimates of events/nb-1 • f  hg, • h  2g •  3p0 •  p+p-p0 • Status: • All data reconstructed with DBV-7 completed • Total size of all YBOS output: 40GB circa

25. Outlook for mini-DST production • Proposed format for mini-DST’s • zlib-compressed YBOS • Bank subset essential for physics analysis • Summary banks? • Substreams? • Phase 1: • Mini-DST production in dedicated pass • Phase 2: • Mini-DST production as part of data processing • Phase 1 Status: • Compression Done • Scripts Some work needed • Retained banks Needs definition • Summary banks Needs definition, coding • Substreaming Needs definition • Waiting on physics input • Technical aspects relatively simple • Phase 2 Outlook: More distant • Technically more complicated • E.g.: what to do when files from a given run processed weeks apart? • Solutions exist, but limited resources to devote • (man and machine)