11/21/2002Marcello A. Giorgi1 THE STATUS of BABAR Marcello A. Giorgi Università di Pisa /INFN/SLAC.

11/21/2002 Marcello A. Giorgi 1

THE STATUS of BABAR

Marcello A. Giorgi

Università di Pisa /INFN/SLAC

http://www.unipi.it/princ.html


OUTLINE

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


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)


IR2 Schematics


DCH damage and repair

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


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 (< 50 ml/min) Electrically grounded 5 mm clearance to support tube No damage to nearby wires


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!


Rotated Tail

FixedSections

Slipped Milpac

SVT Recovered Sections


SVT & Support Tube Installation


DIRC shutdown main activity: TDC upgrade (I)

New TDC design to allow small dead time up to 1 MHz rates

expectation: rate (kHz) ~ 530 at L=4. 1034 cm2/s

high inefficiency with current design

Issue: background rate versus luminosity:


DIRC shutdown main activity: TDC upgrade (II) TDC chips: 12 (sectors) × 14 (Front End Boards) × 4 (chips)=672

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 !

Sector crate

Front end board


Typical distribution for cosmic data

Occupancy: hit frequency per phototubeDIRC cosmic data

Timing distribution also look very good


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


Absorber Segmentation

7 layers 2 cm

1 layer 7 cm

2 layers 9 cm

2 layers 13 cm

2 layers 10cm

total 85 cm

New Forward EndCap project

Terminology: 19 slots and 15 RPC layers

RPC belt

Slot18/195 brass layers(slot 8,10,12,14,16)


GT/SLAC cosmic test

• Cosmic test at RPC producer General Tecnica and SLAC– QA test

» Gas leakage test before and after shipping» Dark current

All the RPC with maximal efficiency

All the RPC with maximal efficiency

96%

Radiography HV Plateau

HV [V]

Strip Occ.


Barrel IFR Upgrade

The problem: dying RPCs.

Muon selectors losing efficiency impacting physics

Decreasing efficiencySome RPC completely off

Decreasing efficiencySome RPC completely off


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.


TriggerL1 Trigger: 1.1khz @ 4x1033

L3 Trigger: 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: BB>99%, udsc~97% Fiducial: ee,>99%, ~92%.


Level-1 Drift-Chamber Trigger Upgrade

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.

(will run new system in parallel to exisitng system initially with DCH trigger fiber signalsplitting).

ZPD prototype (9U VME): XilinX Vertex II 3000/4000 FPGAs.120MHz databus & internal logic.

Need to contain L1 rate to <3 Khz at future high luminosity running to avoid DAQ bottleneck in DCH frontend data shipping.


Oep Ntuple

Objy

Root

HPSS

Event Data Flow AnalysisSkims

Production

SimProdPrompReco

COMPUTING


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


Initial targets for PEP-II and BaBar:New environment: high luminosity asymmetric colliderSearch 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 potentialProbe CKM model new physics ?Rare decays, searches (not only B) new physics ?Along the way: constrain heavy quark models

BaBar Physics Analysis

25 ICHEP’02submissions

Journal publ.in preparation

Active analysissubjects (2)


CP violation: sin2

cp

sin2 = 0.741 0.067 (stat) 0.034 (syst)sin2 = 0.741 0.067 (stat) 0.034 (syst)

cp

sin2 = 0.755 0.074 sin2 = 0.723 0.158

hep-ex/0207042, Submitted to PRL


Osaka -2002Rome- 2001

Amsterdam- 2002

CP discovery

in B sector


Towards sin2eff

0.02 0.34( ) 0.05( )

0.30 0.25( ) 0.04( )

S stat syst

C stat syst

0.02 0.34( ) 0.05( )

0.30 0.25( ) 0.04( )

S stat syst

C stat syst

B→

B0

0.180.19

0.250.25

0.45 ( ) 0.09( )

0.16 ( ) 0.07( )

C stat syst

S stat syst

0.180.19

0.250.25

0.45 ( ) 0.09( )

0.16 ( ) 0.07( )

C stat syst

S stat syst

0.080.080.22 ( ) 0.07( )CPA stat syst 0.080.080.22 ( ) 0.07( )CPA stat syst


Semileptonic B Decays and |Vcb|

Fit to sum of spectra from: B D e , D* e ,

D** e , D(*) e

BR(BX e ) = (10.87 0.18stat 0.30sys)%BR(BX e ) = (10.87 0.18stat 0.30sys)%

|Vcb| = 0.0423 0.0017exp 0.0020theory

|Vcb| = 0.0423 0.0017exp 0.0020theory

Integration over spectrum &

extrapolation to pl*=0

Relation to |Vcb| byHoang-Ligeti-Monahar


Penguins and rare b decaysEM 54.6 fb-1 40.43

0.23

S

10(theory))0.37(sys)

0.36(stat)(3.88)X(B

B

047.0*BB

..%90109.1B 6

KBB

LCBExclusive measurements:also interesting for |Vtd/Vts|2

EW 85M BB pairs60.110.24

0.180.20 10)(0.78)lKl(B

B

C.L. 90% @103.0

100.28)(1.68)llK(B6

60.680.58

*

B

QCD

B K0S 51 events

0.520.50sin 2 0.19 ( ) 0.09( ) stat syst

600

6*

6

109.05.1

7.17.8

108.00.12.9

pairs B1060

SKBBF

KBBF


What next? Probe CKM in detail…

sin2 uncertainty still far from systematic limitSeveral modes can give information on each side and angleAll actively analyzed in BaBar. Key element: integrated

luminosity!

B,

BKS

BD(*)+D(*)-

BDKB

VtdVtb

*VudVub

*

VcdVcb

*

bulB() l

bcl

B() B0 Mixing


…and with higher and higher luminosity:

Rare B decays, for instance:Loop-mediated, FCNC: b sl+l-, b s , b sLeptonic: 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 PhysicsSearch for mixing and CP violation in D meson decays, …

Rare decays, including LFV


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


Hadronic event from OPR

Nov.18,2002


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


The enthusiatic people of BABAR


BACKUP


SVT Split


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


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


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


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.


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.


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.

11/21/2002Marcello A. Giorgi1 THE STATUS of BABAR Marcello A. Giorgi Università di Pisa /INFN/SLAC.

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Transcript of 11/21/2002Marcello A. Giorgi1 THE STATUS of BABAR Marcello A. Giorgi Università di Pisa /INFN/SLAC.