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LHCb status report

LHCb Status Report. Andrei Golutvin Imperial College ITEP / CERN. LHCb status report. Outer/Inner Tracker. 21 stations of Si wafer pairs with r and f strip readout. Beam 2. Beam 1. Muon ECAL/HCAL RICH2 Tracker Magnet TT RICH1 VELO.

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LHCb status report

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  1. LHCb Status Report Andrei Golutvin Imperial College ITEP / CERN LHCb status report Outer/Inner Tracker 21 stations of Si wafer pairs with r andf strip readout Beam 2 Beam 1 Muon ECAL/HCAL RICH2 Tracker Magnet TT RICH1 VELO

  2. A few highlights from LHCb thanks to the outstanding start-up LHC performance MUON XY XZ RICH2 CALO Magnet OT VELO Z Extended VELO signed rZ view p p

  3. ECAL reconstructs p0signal Very first data : 23November 2009, No B-field <m> = (133 ± 3) MeV/c2 (perfect agreement with the PDG value) σ = (11 ± 4) MeV/c2 LHCb data (preliminary) Now p0 peak can be routinely monitored on-line: Mgg (MeV/c2) Mgg (MeV/c2)

  4. The masses of the reconstructed KS and L in agreement with the PDG values Tracking without VELO Tracking detectors were well calibrated at the start-up ! • M(KS) = 496.9 ± 0.3 MeV/c2 • = 11.0 ± 0.4 MeV/c2 • M(KSPDG) =497.7 MeV/c2 • M(L) = 1115.6 ± 0.2 MeV/c2 • = 3.1 ± 0.2 MeV/c2 • M(LPDG) =1115.7 MeV/c2

  5. The masses of the reconstructed KS and L in agreement with the PDG values Using full tracking power, including VELO • M(KS) = 497.3 ± 0.2 MeV/c2 • = 4.3 ± 0.1 MeV/c2 • M(KSPDG) =497.7 MeV/c2 • M(L) = 1115.6 ± 0.1 MeV/c2 • = 1.4 ± 0.1 MeV/c2 • M(LPDG) =1115.7 MeV/c2 Accuracy will be further improved after complete alignment

  6. pp interaction vertex (VELO) VELO can not be fully closed at √s = 900 GeV; each side is 15 mm away from the nominal position VELO moved in and out routinely; Kept 30 mm away during injection X, mm Y, mm Measured dimensions of the luminous region: sX ≈ sY ≈ 0.3 mm sZ≈ 40 mm

  7. Beam 2: beam gas event Beam 1: beam gas event XZ plane YZ plane Beam 1 Beam 2 Beam 1 Beam 2 Impact of LHCb dipole magnet: LHC beams cross at 2 mrad angle in horizontal plane as expected at the full magnetic field

  8. RICH identifies charged kaons LHCb data (preliminary) RICH 1 Orange points – photon hits Continuous lines – expected distribution for each particle hypothesis (proton below threshold) Kaon ring RICH2 RICH 2 LHCb data (preliminary) Kaon ring Cherenkov angle (rad) Detailed calibration and alignment in progress

  9. MIP identification using ECAL, HCAL & Muon (MIP = Minimum Ionizing Particle) ECAL ECAL + MUON LHCb data (preliminary) LHCb data (preliminary) EECAL (MeV) HCAL + ECAL HCAL + MUON LHCb data (preliminary) LHCb data (preliminary) EHCAL (MeV)

  10. Converted photons reconstructed using Tracking and ECAL LHCb data (preliminary) M(e+e-) < 200 MeV/c2 for any pair of oppositely charged tracks LHCb data preliminary p0 E / P p0 reconstructed using converted photons: p0 ge+e- ( ge+e- ) Background subtracted • M(p0) = 133 MeV/c2 • = 15 MeV/c2 (slightly worse • than for p0gg due to bremstrahlung)

  11. Events with dimuons • Selection: • Oppositely charged muon candidates • from the interaction region • Vertex quality & Muon identification • There is acandidate with • M(mm) = 3035 MeV/c2, • PT1= 2.2 GeV, PT2=1.2 GeV LHCb data preliminary Extended Muon region

  12. Summary of 8 days LHCb data taking 540317 187500 343360 Enough data to understand the detector performance in order to be in even better shape for physics at √s = 7 TeV

  13. High Energy Fill at √s = 2.36 TeV (still not sufficient to close VELO; looking forward for stable beams at higher energy) No stable beam flag  Si detectors were switched off On: OT, RICH, CALO and MUON ~30k events reconstructed ECAL Cluster multiplicity LHCb data preliminary 2x450GeV LHCb data preliminary 2x1.18 TeV ET (ECAL + HCAL), GeV

  14. Very Efficient Data Processing • Two copies of raw data are made • One copy at CERN • One copy distributed over tier1 sites • Reconstruction automatically triggered by presence of new raw data file • DST typically available for physics analysis within one hour of file closed at the pit • Dominated by migration time to mass storage (longer wait for small files) • Reconstruction jobs last a few minutes (small files, low multiplicity events). Design is 24 hours • 2 Reprocessings of full dataset • Completed on the grid in <2 hours CERN site busy with user analysis

  15. Thanks to the team effort the LHCb detector works very well ! We are ready for the Long Physics Run in 2010 800 members 15 countries 54 institutes

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