LHCb computing in Russia Ivan Korolko (ITEP Moscow) Russia-CERN JWGC, October 2005

LHCb in numbers LHCb nominal Luminosity→ 2x10 32 cm -2 s -1 rate of p-p interactions→ 2x10 7 per second HLT output→ 2000 Hz RAW data per year→ 2x10 10 events (500 TB) Events with b quarks → 10 5 per second (!) acceptance for b-events → 5-10% Br. for CP channels → ~10 -5 Number of CP channels → ~50 ~5 signal events in every second of LHCb operation – GREAT! Have to select them from 1.5x10 7 background events Signature of LHCb signals is not very bright (P t, vertex) Estimation of S/B ratio is a REAL CHALLENGE

LHCb computing documents LHCb computing modelLHCb LHCb computing TDRCERN/LHCC

LHCb computing model (1) 1. RAW data → 2x10 10 events/year 25 kB/event, 500 TB/year 1 copy stored at CERN and 1 copy in Tier1 centers 2. Reconstruction → 2.4 kSI2k.sec/event 2 times per year → 7 months and 2 months CPU needs : 12MSI2k.years storage: 500 TB (rDST data for stripping) 1 copy stored across CERN and Tier1 centers

4. Analysis → 0.3 kSI2k.s/event 140 physicists, 2 jobs/week, 3x10 6 events CPU needs : x(n-1) MSI2k storage: 200 TB run at CERN, Tier1 and some Tier2 centres LHCb computing model (2) 3. Stripping → 2.1x10 9 events/year kB/event, 139 TB/year (DST) 4 times per year (1 month) stored at CERN, Tier1 and some Tier2 centres

LHCb computing model (3) 5. MC production → 4x10 9 events/year ~50 kSI2k.sec/event (8 MSI2k.years) 400 kB/event 160 TB to store only triggered events (4x10 8 ) produced at Tier2 centres stored at CERN and Tier1 centres LHCb trigger differs significantly from ATLAS and CMS

Russian participation in LHCb IHEP(Protvino), INP (Novosibirsk), INR (Troitsk), ITEP (Moscow), PNPI (St.Petersburg) SPD and Preshower, ECAL, HCAL, MUON system and RICH mirrors Design, construction and maintenance of detectors Development of reconstruction algorithms Historical interests in B physics

Russian participation in LHCb Physics interests of Russian scientists: Studies of CP violation with B and D hadrons Rare (forbidden) decays of B and D hadrons Radiative penguin decays pf B mesons (non SM physics) Spectroscopy of B hadrons High P t jets (W and Z bosons, t quarks, Higgs, exotica) Canonical users in Russian institutes: IHEP-7, INP-5, INR-5, ITEP-7, PNPI-6

What to “compute” in Russia ? There are 2 main tasks: 1. Provide facilities for LHCb data analysis in all participating Russian institutes. 2. Fulfill collaboration requirements

Computing in Russia (1) 1. Partially store reconstructed data (rDST) most recent copy for the current year 1 copy for all previous years storage: x(n-1) TB(b inclusive) 2. Store stripped data (DST) most recent copy for the current year 1 copy for all previous years storage: x(n-1) TB

Computing in Russia (2) 3. Run stripping jobs on stored rDST B-inclusive sample – 9x10 9 events/year CPU needs : 0.06 MSI2k.years CPU power : 0.72 MSI2k.years (finish in one month) data reduction factor ~100 TAG:9 + 9x(n-1) TB 4 stripping passes per year→0.3 MSI2k.years rerun stripping during first years of LHCb operation

4. Run analysis jobs(20% of LHCb) Computing in Russia (3) CPU→ x(n-1) MSI2k.years storage: x(n-1) TB MC analysis also requires some resources B-exclusive dimuonD*B-inclusive physicists

Computing in Russia (4) 5. MC production(~10% of LHCb) CPU→0.8 MSI2k.years storage: 3 TB 6. Calibration, reconstruction algorithms CPU→0.2 MSI2k.years storage: 30 TB (hard to estimate now)

LHCb Tier2 cluster in Russia CPU MSI2k disks TB tapes TB partial Tier1 functionality (DST stripping, analysis)

History of LHCb DCs in Russia K events, 1% contribution only one centre (ITEP) M events, 3% contribution all 4 our centers (IHEP,ITEP,JINR,MSU) M events, 5% contribution started to use LCG 2005 PNPI and INR have joined

Plans MC production for the collaboration routine task (running in 5 Russian centers) participation in DC06 Distributed analysis extensive tests of GANGA (CERN, Tier1) deployment of GANGA in Russia participation in SC Significant increase of resources in 2006 learn how to operate much larger centers