Status Report on Data Reconstruction May 2002 C.Bloise Results of the study of the reconstructed events in year 2001 Data Reprocessing in Y2002 DST production Monte Carlo samples Data taking in Y2002 Summary

Y2001 Data Study of the data samples taken at different background levels –Reconstruction improved : more robust selection criteria implemented

Data Reconstruction Updates Filtering Procedure –Pre-filtering of cosmic muons removed –Rejection of events with a big number of calorimeter cells removed Selection criteria –Large angle bhabha and  selection improved –Tag devoted to k S       , k L  , k L      added –Charged kaon selection criteria completely revised Calorimeter Calibration –Refined time calibration introduced on Oct, 17 th –Procedure to correct the rest of data created

Reconstruction - Y2001 raw EmC recon. DC recon. Evt. Class bha kpm ksl rpi rad clb flt afl Evt. Class cos prescaled cosmic MB cosmic ÷10 ÷100 Bhahba

Reconstruction - Y2002 EmC recon. DC recon.Evt. Class bha kpm ksl rpi rad clb flt afl MB cosmic ÷100 L3 filter cosmic raw L2 Triggers

To generate an homogeneous data set on respect filtering criteria and calibration quality to include the new selection criteria developed for charged and neutral kaons for improving the luminosity measurement. Reprocessing from January, till May, with triggers analyzed Data Reprocessing

Computing & Data Storage 2002 krunc Run Control & DFC Online farm fibm fibm08 Offline farm 22 IBM B80 88 CPU 2.7 KHz : total farm power 10 Enterprise CPU MonteCarlo DSTs 2 IBM + 2 Sun Users Reconstruction output 560 GB Job control areas 200 GB Recalled Data from Tape 2200 GB Magstar 5,500 Cassettes 12 Tape Units 220TB fibm01 DB2 Server 2 IBM H80 TSM/NFS Servers 2 IBM H70 AFS Servers 2 TByte 1.4 TByte Catalyst 6000

pb -1 /day KHz pb -1 /100Mtri Feb,17 th May, 7 th Day by day Data Reprocessing

180 pb -1 collected in different run periods, at different luminosities and background levels Data Taking Period Max luminosity (cm -2 s -1 ) Sample Luminosity ( pb -1 ) Maximum reconstructable luminosity (pb -1 /day) Data volume (Gbytes/pb -1 ) Nov-Dec Sep-Oct Jun-Jul Apr Y2000 and Y2001 Data set - CPU power cost and data volumes stored for different data taking conditions Different run conditions imply different CPU power needed per pb -1 different data volumes stored per pb - 1 Data Taking in Y2001

Besides the reconstructed data sample, the DSTs are produced, with a selected information content reducing by a factor of 10 the data volume for the analyses. These files are created immediately after the data reconstruction completion to take advantage of the availability of the files on disk. Excluding the charged kaon DSTs, that have not been created so far, we have a total of 6 GB/pb -1 as DST volume. The charged kaon DSTs will have both, the biggest event size, and the largest event sample: 10 6 events/pb -1 X 5 KBytes/event, e.g. 5 GBytes/ pb TBytes of disk space devoted now to DSTs on the new servers. To allow an efficient multi-user access to the entire DST sample (6 TBytes by the end of data taking) we need to increase disk space to 4 Tbytes by the end fo the year DSTs for the analyses

Monte Carlo 8 Sun-Enterprise 450 are dedicated to Monte Carlo generation and reconstruction Event production is based on procedures based on the information (random seeds, input cards, job status,…) in the DB Computer power correspond to 2.5  events completed per day The most demanding task is the study of the background topologies Work in progress – of Ks      decays (60 pb-1) ~25% available – of  decays ( 5 pb-1) ~50% available

The Offline farm can process 2,700 triggers/s Y2002 Data : May 3 rd – May 17 th : Trigger rate 1.5 KHz (Level 3) 0.04 nb -1 s  Bhabha s Bck s -1 40% of the farm available for users and DST production Enough power is left for handling further improvements in the luminosity. Y2002 Data Reconstruction

Day by day 2002 Data Reconstruction May, 3 rd May, 17 th pb -1 /day pb -1 /100Mtri KHz

Dafne luminosity (cm -2 s -1 ) Maximum reconstructable luminosity (pb -1 /day) Data volume (Gbytes/pb -1 ) Raw volume (GB/pb -1 ) Filtered volume (GB/pb -1 ) Reconstructed volume (GB/pb -1 ) Bhabhas volume (GB/pb -1 ) Data taking conditions May 2002 From 8 pb -1 of integrated luminosity Total capacity of the Library, inclusive of the Y2001 data set, and assuming the present Da  ne running conditions, is 400 pb -1 corresponding to 100 full days of data taking, and if we scratch the filtered sample, is 570 pb -1 corresponding to 177 full days of data taking. Y2000-Y2001 data fill about 105 Tbytes, e.g cassettes, corresponding to 54% of the Tape Library storage space.

SUMMARY Disk space : Multi-user access to DSTs (6 Tbytes expected by the end of the year ) requires additional 3 Tbytes by the end of the year. Library : It will be full by the end of the year. As soon as they will be available on the market (Summer 02), and according to the data taking status we expect to update the tape drives to increase the total capacity by 50% New storage solutions are under study for the year 2003 data taking. Computing Power : Less than 50% of the approved total computing power has been acquired so far. It is enough for the online reconstruction, DST production, to generate MonteCarlo samples and to perform the ongoing analyses It is marginal for any reprocessing campaign, as the 4-full-months needed to reconstruct 180 pb -1 demonstrate.