THE STATUS of BABAR

1
THE STATUS of BABAR
Marcello A. Giorgi Università di Pisa
/INFN/SLAC
2
OUTLINE

• Down period and detector activity
• Ready to startup
• Physics Analysis
• Toward future achievements

3
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)

4
IR2 Schematics
5
DCH damage and repair

• On July 31, during removal of the support tube,
  a bolt head cracked the DCH Be inner cylinder.

6
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

• Helium tight (lt 50 ml/min)
• Electrically grounded
• 5 mm clearance to support tube
• No damage to nearby wires

7
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!

8
SVT Recovered Sections
9
SVT Support Tube Installation
10
DIRC shutdown main activity TDC upgrade (I)
Issue background rate versus luminosity
expectation rate (kHz) 530 at L4. 1034
cm2/s
high inefficiency with current design
? New TDC design to allow small dead time up to 1
MHz rates
11
DIRC shutdown main activity TDC upgrade (II)
TDC chips 12 (sectors) 14 (Front End Boards)
4 (chips)672
Sector crate
Front end board
Boards - removed and sent to external company
for chips exchange
- 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 !
12
DIRC cosmic data
Occupancy hit frequency per phototube
Typical distribution for cosmic data
Timing distribution also look very good
13
IFR Forward Endcap

• The improvement in the Forward Endcap
• REPLACEMENT OF RPC
• Insertion of BRASS to increase absorber thickness
• ADDITIONAL LAYER 1819 (double gap)
• ADDITIONAL BELT around Endcap
• New gas system
• New HV distribution

14
New Forward EndCap project
Terminology 19 slots and 15 RPC layers
RPC belt
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 total 85 cm
15
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
16
Barrel IFR Upgrade
Decreasing efficiency Some RPC completely off
The problem dying RPCs.
Muon selectors losing efficiency impacting
physics
17
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.

18
Trigger

• L1 Trigger 1.1khz _at_ 4x1033

L3 Trigger Output 130Hz _at_ 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
eBBgt99, eudsc97 Fiducial eee,mmgt99,
ett92.
19
Level-1 Drift-Chamber Trigger Upgrade
Need to contain L1 rate to lt3 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)
• Interface boards of 3 types
• All boards in prototyping phase.
• Expected production in Jan/03.
• Commissioning starts Mar/03.
• (will run new system in parallel
• to exisitng system initially
• with DCH trigger fiber signal
• splitting).

ZPD prototype (9U VME) XilinX Vertex II
3000/4000 FPGAs. 120MHz databus internal logic.
20
COMPUTING
Event Data Flow
Analysis
Skims
HPSS
Objy
Ntuple
Oep
SimProd
PrompReco
Root
Production
21
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

22
BaBar Physics Analysis

• Initial targets for PEP-II and BaBar
• New environment high luminosity asymmetric
  collider
• 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
• What next? Discovery potential
• Probe CKM model ? new physics ?
• Rare decays, searches (not only B) ? new
  physics ?
• Along the way constrain heavy quark models

23
CP violation sin2?
hcp-1
hcp1
sin2b 0.723 ? 0.158
sin2b 0.755 ? 0.074

• sin2b 0.741 ? 0.067 (stat) ? 0.034 (syst)

hep-ex/0207042, Submitted to PRL
24
CP discovery in B sector
Osaka -2002
Rome- 2001
Amsterdam- 2002
25
Towards sin2?eff
B0 ? ? ?
B0 ? p p
26
Semileptonic B Decays and Vcb
Fit to sum of spectra from B ? D e n, D e
n, D e n, D() p e n

• Integration over spectrum
• extrapolation to pl0

BR(B?X e n) (10.87 ?0.18stat ?0.30sys)
Relation to Vcb by Hoang-Ligeti-Monahar
Vcb 0.0423 ?0.0017exp ? 0.0020theory
27
Penguins and rare b decays
EM 54.6 fb-1
Exclusive measurements also interesting for
Vtd/Vts2
EW 85M BB pairs
QCD
B ? ?K0S 51 events
28
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?pp, rp
b?ul?
B0 Mixing
B?(?????) l?
B?(???) ?
B0?y(?),f,h? KS B0?D()D()-
B?DK B ?K?, ? ?
b?cl?
29
and with higher and higher luminosity

• Rare B decays, for instance
• Loop-mediated, FCNC b ? sll-, b ?s ??, b ? s?
• Leptonic B ? ??,
• Unique possibility at B factories fully
  reconstructed B tag
• ? 0.1 efficiency, very useful for channels with
  missing energy (?)
• Just began to exploit this possibility
• Charm and Tau Physics
• Search for mixing and CP violation in D meson
  decays,
• Rare ? decays, including LFV

30
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

31
Hadronic event from OPR
Nov.18,2002
32
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
33
The enthusiatic people of BABAR
34
BACKUP
35
SVT Split
36
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

37
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 effby accumulating charge

38
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

39
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.

40
From task Force

• PEPIIBABAR 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 rg, a and g with
  pp (rp) DK (DKp) rare decays (penguins), non b
  physics will benefit (they need) from higly
  increased statistics.

41
From task force

• BABAR is a pretty good detector and it is very
  difficult to improve it significantly
• Some gain for pp (similar or better for rp),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.