THE STATUS of BABAR Marcello A. Giorgi Università di Pisa /INFN/SLAC 11/21/2002 Marcello A.
Download ReportTranscript THE STATUS of BABAR Marcello A. Giorgi Università di Pisa /INFN/SLAC 11/21/2002 Marcello A.
THE STATUS of BABAR Marcello A. Giorgi Università di Pisa /INFN/SLAC 11/21/2002 Marcello A. Giorgi 1 OUTLINE • • • • Down period and detector activity Ready to startup Physics Analysis Toward future achievements 11/21/2002 Marcello A. Giorgi 2 Down period Activity (DETECTOR) • The main and programmed activities on the BABAR Detector: – the intervention on the IFR End Cap (muon/KL detector ). – The installation of new TDC in the Dirc . – The maintainance of SVT (possible because of the extraction from BABAR of Support Tube containing SVT, beam pipe and magnetic elements of interaction region) 11/21/2002 Marcello A. Giorgi 3 IR2 Schematics 11/21/2002 Marcello A. Giorgi 4 DCH damage and repair • On July 31, during removal of the support tube, a bolt head cracked the DCH Be inner cylinder. 11/21/2002 Marcello A. Giorgi 5 DCH Damage and Repair, Summer 2002 " " " " " " Support tube hit inner cylinder 6" x 1" crack in beryllium section No environmental contamination IC still about 7x structural load Filled with epoxy Covered with Al " " " " 11/21/2002 Helium tight (< 50 ml/min) Electrically grounded 5 mm clearance to support tube No damage to nearby wires Marcello A. Giorgi 6 SVT work SVT has been un-cabled,taken to the clean room, split in two halves and removed from the B1 magnets •Once the SVT was exposed electrical tests and visual inspections were performed. We discovered the reason for some of the failures of the 9 non functioning readout sections,some modules fixed! • 11/21/2002 Marcello A. Giorgi 7 SVT Recovered Sections Rotated Tail Slipped Milpac 11/21/2002 Fixed Sections Marcello A. Giorgi 8 SVT & Support Tube Installation 11/21/2002 Marcello A. Giorgi 9 DIRC shutdown main activity: TDC upgrade (I) Issue: background rate versus luminosity: expectation: rate (kHz) ~ 530 at L=4. 1034 cm2/s high inefficiency with current design New TDC design to allow small dead time up to 1 MHz rates 11/21/2002 Marcello A. Giorgi 10 DIRC shutdown main activity: TDC upgrade (II) TDC chips: 12 (sectors) × 14 (Front End Boards) × 4 (chips)=672 Sector crate Boards: - removed and sent to external company for chips exchange Front end board - re-coded and tested in test bench at SLAC - re-installed in detector and fully tested with calibration data: OK October 11th 2002 TDC upgrade successful ! 11/21/2002 Marcello A. Giorgi 11 DIRC cosmic data Occupancy: hit frequency per phototube Typical distribution for cosmic data Timing distribution also look very good 11/21/2002 Marcello A. Giorgi 12 IFR Forward Endcap The improvement in the Forward Endcap • REPLACEMENT OF RPC • Insertion of BRASS to increase absorber thickness • ADDITIONAL LAYER 18&19 (double gap) • ADDITIONAL BELT around Endcap • New gas system • New HV distribution 11/21/2002 Marcello A. Giorgi 13 New Forward EndCap project RPC belt Terminology: 19 slots and 15 RPC layers Slot18/19 5 brass layers (slot 8,10,12,14,16) Absorber Segmentation 7 layers 2 cm 1 layer 7 cm 2 layers 9 cm 2 layers 13 cm 2 layers 10cm 11/21/2002 Marcello A. Giorgi total 85 cm 14 GT/SLAC cosmic test All the RPC with maximal efficiency • Cosmic test at RPC producer General Tecnica and SLAC – QA test » Gas leakage test before and after shipping » Dark current Radiography HV Plateau Strip Occ. 96% HV [V] 11/21/2002 Marcello A. Giorgi 15 Barrel IFR Upgrade Decreasing efficiency Some RPC completely off The problem: dying RPCs. Muon selectors losing efficiency impacting physics 11/21/2002 Marcello A. Giorgi 16 Barrel IFR Upgrade • We are now in the middle of the process to understand the best way to fix this problem. ‘Remediation’ has not been a success. • Working committee formed to recommend an upgrade technology. There are three candidates: improved RPCs with better Q/C, Limited Streamer Tubes, and Scintillator read by APDs. • Decision expected by January. • Access for replacement of current RPCs is mechanically complex: significant engineering needed. Expect to upgrade in 2004 and 2005 to avoid an extremely long shutdown. 11/21/2002 Marcello A. Giorgi 17 Trigger L1 Trigger: L3 Trigger: 1.1khz @ 4x1033 Output 130Hz @ 4x1033 Software trigger executes on 47 Linux farm nodes (1.4Ghz Pentium-III dual CPU with Gbit Ethernet, recently replaced 60 Sun Ultra-5 nodes). L3 algorithms run at ~4ms/event. Trigger Strategy: Goal: Trigger on physics with high, stable and measurable efficiency. Strategy: Orthogonal tracking and calorimeter triggers with high efficiency at both L1 and L3 for most physics sources. Efficiency: Total: eBB>99%, eudsc~97% Fiducial: eee,mm>99%, ett~92%. 11/21/2002 Marcello A. Giorgi 18 Level-1 Drift-Chamber Trigger Upgrade Need to contain L1 rate to <3 Khz at future high luminosity running to avoid DAQ bottleneck in DCH frontend data shipping. Z information needed, therefore the tracking trigger must be redesigned The upgrade task: 24 Track segment finders (TSF) 8 Z-Pt-Discriminators (ZPD) 33 Interface boards of 3 types All boards in prototyping phase. Expected production in Jan/03. Commissioning starts Mar/03. ZPD prototype (9U VME): XilinX Vertex II 3000/4000 FPGAs. 120MHz databus & internal logic. 11/21/2002 (will run new system in parallel to exisitng system initially with DCH trigger fiber signal splitting). Marcello A. Giorgi 19 COMPUTING Event Data Flow Analysis Skims HPSS Objy Oep PrompReco Ntuple SimProd Root Production 11/21/2002 Marcello A. Giorgi 20 Computing Model Discussions • Current Model defined in 2000 (April review suggested an update) • BaBar has 4 Tier-A sites (France, Italy, UK, US) – New German centre (probably) next year – Looking at how to best utilise these distributed resources (BaBar GRID is one tool for this) • Multiple analysis formats (now) – Objectivity, ROOT and Ntuples – Multi-step process – Problems found at any level need fixes propagated to other formats • A committee is currently considering the computing model with increased luminosity within a limited resource scenario (in both people and money) • Attempting to replace all three with ROOT – Ntuples will still be needed, but to a much lesser extent • Report will be internally reviewed on December 6th, 7th 11/21/2002 Marcello A. Giorgi 21 BaBar Physics Analysis Initial targets for PEP-II and BaBar: 25 ICHEP’02 New environment: high luminosity asymmetric collider submissions Search for CP violation in B mesons decays: found ! Establish methods for precision B physics, rare B decays some highlights on Run 1 + Run 2 Journal publ. in preparation What next? Discovery potential Probe CKM model new physics ? Active analysis Rare decays, searches (not only B) new physics ? subjects (2) Along the way: constrain heavy quark models 11/21/2002 Marcello A. Giorgi 22 CP violation: sin2 hcp=-1 hcp=+1 sin2 = 0.755 0.074 sin2 = 0.723 0.158 sin2 = 0.741 0.067 (stat) 0.034 (syst) hep-ex/0207042, Submitted to PRL 11/21/2002 Marcello A. Giorgi 23 CP discovery in B sector Osaka -2002 Rome- 2001 Amsterdam- 2002 11/21/2002 Marcello A. Giorgi 24 Towards sin2eff B0 → + ACP = -0.22+-0.08 0.08 ( stat ) 0.07( syst ) C = 0.45+-0.18 0.19 ( stat ) 0.09( syst ) S = 0.02 0.34( stat ) 0.05( syst ) C = -0.30 0.25( stat ) 0.04( syst ) 11/21/2002 B0 S = 0.16+-0.25 0.25 ( stat ) 0.07( syst ) Marcello A. Giorgi 25 Semileptonic B Decays and |Vcb| Fit to sum of spectra from: B D e n, D* e n, D** e n, D(*) e n BR(BX e n) = (10.87 0.18stat 0.30sys)% |Vcb| = 0.0423 0.0017exp 0.0020theory 11/21/2002 Marcello A. Giorgi Integration over spectrum & extrapolation to pl*=0 Relation to |Vcb| by Hoang-Ligeti-Monahar 26 Penguins and rare b decays B(B XS ) = (3.88 0.36(stat) EM 54.6 fb-1 0.43 0.37(sys) +-0.23 (theory)) 10-4 Exclusive measurements: also interesting for |Vtd/Vts|2 EW 85M BB pairs BB 1.9 106 90% C.L. BB BB K * 0.047 + 0.11 -6 B(B Kl+ l - ) = (0.78+-0.24 ) 10 0.20- 0.18 -6 B(B K *l + l - ) = (1.68+-0.68 0.58 0.28) 10 3.0 10 -6 @ 90% C.L. QCD B 11/21/2002 BF B 60106 B pairs BF B K * = 9.2 1.0 0.810-6 K0 S 51 events 0 + 1.7 K S0 = 8.7 0.9 10-6 - 1.5 sin 2 = - 0.19+-0.52 0.50 ( stat ) 0.09( syst ) Marcello A. Giorgi 27 What next? Probe CKM in detail… sin2 uncertainty still far from systematic limit Several modes can give information on each side and angle All actively analyzed in BaBar. Key element: integrated luminosity! B0, buln B(,,) ln * VudVub BDK B K, 11/21/2002 * B0 Mixing B(,) VtdVtb * VcdVcb bcln Marcello A. Giorgi B0y,,h KS B0D(*)+D(*)28 …and with higher and higher luminosity: Rare B decays, for instance: Loop-mediated, FCNC: b sl+l-, b s nn, b s Leptonic: B tn, … Unique possibility at B factories: fully reconstructed B tag 0.1% efficiency, very useful for channels with missing energy (n) Just began to exploit this possibility Charm and Tau Physics Search for mixing and CP violation in D meson decays, … Rare t decays, including LFV 11/21/2002 Marcello A. Giorgi 29 BABAR back again and READY !! • After the down period BABAR is ready to take data in better shape than in the last July • We are ready for higher luminosity with hardware and software • We have an exciting Physics Program beyond the original scientific mission • We are prepared to improve our muon detection (the technology of the barrel IFR will be chosen in January 2003) • We continuously monitor our computing model to improve it and to make our Physics Analysis more effective 11/21/2002 Marcello A. Giorgi 30 Hadronic event from OPR Nov.18,2002 11/21/2002 Marcello A. Giorgi 31 Preliminary from task force on Long Term Upgrades The task Force will deliver soon the written report to the collaboration Some Highlights: BABAR is a pretty good detector: very difficult to improve it!! (IFR is the only intervention needed) Only a few channels are systematically limited below 1 ab-1 ; many topics would benefit from 2-3 ab-1 or more We need to integrate higher luminosity, well beyond 0.5 ab-1, to better constrain the Unitarity triangle, to study rare decays and try to open windows on New Physics. More resources to PEPII would be beneficial for Physics 11/21/2002 Marcello A. Giorgi 32 The enthusiatic people of BABAR 11/21/2002 Marcello A. Giorgi 33 BACKUP 11/21/2002 Marcello A. Giorgi 34 SVT Split 11/21/2002 Marcello A. Giorgi 35 SVT Current Status • In July 9/208 readout sections were not working. NOW: • 3 of them fixed. • 3 read-out sections still under investigation • 3 can not be fixed: • No new non functioning read-out section has been introduced. • We lost redundancies on 2 modules 11/21/2002 Marcello A. Giorgi 36 Barrel repair •Four major activities –New HV distribution •Replace plastic boxes •FEC fixing •Major failure in Feb 2002 –Gas distribution •Remote monitoring –RPC remediation •Try to increase RPC eff by accumulating charge 11/21/2002 Marcello A. Giorgi 37 Computing Online • Replaced initial Solaris farm – Installed in 98/99 • 50 Linux machines – Extra capacity to cope with increased luminosity – Allows better rejection of background in Level 3 11/21/2002 Marcello A. Giorgi 38 Preliminary report from the Task Force on “Long Term Upgrades” Roy Aleksan and David MacFarlane have reported last September 2002 at the collaboration meeting held London on the activity of the Task Force set in December 2001. The final report is expected soon. Meanwhile some important considerations can be extracted from the evaluation of the task force. 11/21/2002 Marcello A. Giorgi 39 From task Force • PEPII&BABAR have met their CHALLENGE. So far machine and detector have operated very well, beyond what anticipated • No limitation for many modes from systematic effects up to 0.5 ab-1 and for many other channels up to 2-3 ab-1, it will allow us to pursue new goals toward a comprehensive study of CP and search for new physics. • But many topics as Vub,Vtd with , and with () DK (DK) rare decays (penguins), non b physics will benefit (they need) from higly increased statistics. 11/21/2002 Marcello A. Giorgi 40 From task force • BABAR is a pretty good detector and it is very difficult to improve it significantly • Some gain for (similar or better for ),but non overwhelming in improving SVT by adding an extra layer at a smaller radius. The intervention is technically difficult and the risk in reducing beam pipe diameter to 20mm or less could imply high and unquantified operational risk. • A forward veto calorimeter integrated with a modified B1 looks feasible for 2005, but we could not identify so far a significant gain for Physics. 11/21/2002 Marcello A. Giorgi 41