BABAR Future

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BABAR Future
Marcello A. Giorgi
at SLAC B DAY
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Outline

• BaBar Collaboration
• BaBar Mission
• Present Achievements
• What Next.......

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Italy 11/101 INFN, BariU INFN, FerraraU Lab.
Nazionali di Frascati dell' INFN INFN,
GenovaU INFN, MilanoU INFN, NapoliU INFN,
PadovaU INFN, PisaUScuolaNormaleSuperiore INFN,
Roma U "La Sapienza" INFN, TorinoU INFN,
TriesteU The Netherlands 1/2 NIKHEF,
Amsterdam Norway 1/3 U of Bergen Russia 1/9 Bu
dker Institute, Novosibirsk United Kingdom
10/66 U of Birmingham U of Bristol Brunel U U
of Edinburgh U of Liverpool Imperial
College Queen Mary , U of London U of London,
Royal Holloway U of Manchester Rutherford
Appleton Laboratory
USA 38/285 California Institute of
Technology UC, Irvine UC, Los Angeles UC,
Riverside UC, San Diego UC, Santa Barbara UC,
Santa Cruz U of Cincinnati U of Colorado Colorado
State Florida AM Harvard U of Iowa Iowa State
U LBNL LLNL U of Louisville U of Maryland U of
Massachusetts, Amherst MIT U of Mississippi Mount
Holyoke College SUNY, Albany U of Notre Dame Ohio
State U U of Oregon U of Pennsylvania Prairie
View AM U Princeton U SLAC U of South
Carolina Stanford U U of Tennessee U of Texas at
Albany U of Texas at Dallas Vanderbilt U of
Wisconsin Yale
The BABAR Collaboration 10 Countries
75 Institutions 569 Physicists
Canada 4/18 U of British Columbia McGill U U de
Montréal U of Victoria China 1/5 Inst. of High
Energy Physics, Beijing France 5/52 LAPP,
Annecy LAL Orsay LPNHE des Universités Paris VI
et VII Ecole Polytechnique, Laboratoire
Leprince-Ringuet CEA, DAPNIA, CE-Saclay Germany 3
/28 Ruhr U Bochum Technische U Dresden U Rostock

January 14, 2003
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LUMINOSITY

• After a long run period July 1,2002 Babar
  PEPII RUN 2 stopped. RUN 3 has started
  Nov.18,2002 and after the short winter shutdow
  (dec 23-jan 2) operation is continuing in 2003
• RUN 1 RUN 2
• PEP has delivered 98.5 fb-1
• BABAR recorded 83.9 fb-1 (on peak) 9.9 fb-1
  (off peak)
• RUN 3
• PEP has delivered 16.12 fb-1
• BABAR recorded 15.49 fb-1 (on peak) 1.16
  fb-1 (off peak)
• B pair collected (Runs 123) ?112
  Million

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At the end of the present Run 3 (June 29) we
expect more than 40 fb-1
Jun 29
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BaBar Physics Mission

• New environment high luminosity asymmetric
  collider
• 1)Search for CP violation in B mesons decays
  largely predicted by the Standard Model
• 2)Test extensively at this low energy scale the
  Standard Model by measuring precisely enough
  quantities to impose constraints on the Standard
  Model parameters
• CP in b sector is FOUND !
• We move now toward the second part of our mission
• Precision measuremets B physics, rare B decays
• TRY to open windows on new Physics beyond
  Standard Model

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Flavour mixing and CP,T,CPT

Let us remind the Effective Hamiltonian to
describe system, where the mass
eigenstates BH and BL are
and
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Flavour mixing and CP,T,CPT
DmmH-m L ? 2M12 ? 0.5ps-1
1/G ? 1.6 ps
DGGH-GL ? M12Re (G12/M12) DGltltG
SM
CP and T Violation in mixing
As in K sector where ek(p-q)/(pq)
eO(10-3)
SM
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Flavour mixing and CP,T,CPT

• CP an CPT conservation if H11H22

CP and CPT VIOLATION
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Flavour mixing and CP,T,CPT
CPV in Mixing Decay
CPV direct

• Time dependence
• dN?? exp(Dt/tB) ( 1 D (S sin(DmDt) -
  Ccos(DmDt)) ) ? R

D is the mis-tag dilution R is the time
resolution
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CP in the Standard Model
CP is explained in S.M. by the presence of a
phase among the 4 parameters of the flavour
mixing matrix CKM
In the above parametrization ,where l is sin qc ,
h is the parameter contributing to CP
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Representing unitarity relations as Unitarity
Triangles
The unitarity condition of CKM matrix V VVV1
gives several relations between the matrix
elements as VudVub VcdVcb VtdVtb 0 (in
this relation the 3 terms have the same order of
magnitude O(l3) and it can be graphically
represented as a triangle in a complex plane with
sides of comparable length. Other relations have
terms of different order of magnitudes.Ex VusVub
VcsVcb VtsVtb 0
O(l2)
O(l2)
O(l4)
Overconstrain a,b,g and the 4 parameters of CKM
r,h, A,l
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Measurement of sin2b0.741 ? 0.067 ? 0.034
hcp-1
hcp1
sin2b 0.755 ? 0.074
sin2b 0.723 ? 0.158
PRL 89 (2002) 201802
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CP discovery in B sector
Osaka -2002
Rome- 2001
Amsterdam- 2002
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CP,T,CPT

• A simultaneous fit to tagged and untagged data
  gives
• Dm ,sin2b (consistent with previous analysis)
• Acp/ Acp (consistent with no direct CP
  violation (4.5)

90 CL
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CP,T,CPT
From dileptons
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What next for Sin 2b
0.5 ab-1
We can improve the expt. error on sin2b with
luminosity in time dependent asimmetry for
channels as b?ccs O(l2) (golden as J/yKs) or
b?ccd O(l3) (as D () D()-) , where the
leading term gives sin2b
0.5 ab-1
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What next on sin2b

• Measure sin2b also in FK (b?sss pure penguin)

F
K()
B
K
Ks
80 Million B pairs
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Time dependent analysis
Results
Assuming C0 (no direct CPV)
Ssin2b-0.260.51 stat.
On control sample Charged K expected S0 Found
S0.26 0.27 stat.
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Towards sin2?eff Spp and Cpp
B0 ? p p -
BaBar (Br/10-6) B0?pp-4.70.6 0.2 B ? p
p05.5 1.0 0.6 B ? p0p0lt3.6
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a from pp
2d
F
In a full isospin analysis one can measure F and
F from B and B decays with a 4-fold ambiguity
F
Fix BR(p p-) 4.7x10-6, BR(p- p0 )
4.1x10-6 and assuming BR(p0 p0)?
1.0 x10-6
L 0.5 ab-1
L 2.0 ab-1
fb-1
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Bound on d
2d
sin2aeff -0.020.340.05 with 2aeff 2a 2d
Grossman-Quinn bound
F
At present BR(B0?p0p0) lt 3.6?10-6 (81 /fb)
_daeff-a lt 51o
F
best case aeff a lt 190 with 10 fb-1
No significant gain with luminosity
Best case with this method
signal BR 0.5e-6
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Measuring g with B ?D0 K
Gronau,London and Wyler
Take decay B? D01(D02)K where
D01,2(D0D0)/?2 B decay amplitudes can be
written as
and
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Measuring g with B ?D0 K
actual detector ai0.177 perfect vertex
detector ai0.133 (no Bkg)
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New results with full statistics
To complete the measurements odd CP eigenstates
are needed as Ks p0 and Cabibbo suppressed modes
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g from B ?D0 K
Fit sin2g 0.72?0.23 gt g (59.9?10.2)o
Toy MC results for r0.3
0.5 ab-1
Fit with 2ab-1 (perfect) sin2g 0.71?0.14
(sin2g 0.73?0.09) gtg (58.5?7.4)o (g
(58.8?5.5)o)
input value (sin2g0.75)
sin2g
input value (sin2Dd0)
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Measuring Vub
Measure Br(b?uln) on the recoil of fully
reconstructed B. Close kinematics Pl, Q2 and
Mx available
Reco side
Before lepton selection gt3K events/fb-1, S/B0.5
After lepton selection 500 events/fb-1, S/B1.3
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The theoretical error of 10 can be
further reduced at the 5 level using all
information Pl, Q2 and Mx
Assuming a 5 theoretical error and a 5
experimental systematic error, here are the
projections of the error as a function of the
luminosity
Current error
N.B. this estimate neglects the fact that the
full fledged theorethical extraction becomes
feasible only with enough statistics
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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

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...more..

• Charm and Tau Physics
• Search for mixing and CP violation in D meson
  decays,
• Rare ? decays, including LFV

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Integrated luminosity vs physics
BaBar
2006
? 2009 ?
2002
Physics examples choose benchmarks
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From task force on Long Term Upgrades
Some Highlights BABAR is a VERY 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
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SVT

• 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!
  Now only 4 out of 208 sections are not readable.

SVT so far tested for rad hardness up to 4 Mrad
(OK!) rad tests are going on. Partial SVT
replacement of modules already built,tested and
soon ready in Pisa and UCSB is considered by
2005
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New Forward EndCap
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
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Barrel IFR Upgrade
Decreasing efficiency Some RPC completely off
The problem dying RPCs.
Muon selectors losing efficiency impacting
physics
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IFR Barrel Upgrade

• Decision on technology made during Dec
  Collaboration Meeting.
• Project based on LST will be ready (WBS) by end
  of may 23 and will be reviewd in June.
• 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.

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PEPII adiabatic scenario
0.5 ab-1
1.6 x 1034
2006
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A very promising physics program

• We have a and ambitious physics program until the
  end of this decade based on increase of of PEP
  II luminosity with a more aggressive scenario if
  the integrated luminosity would go well beyond
  1/ab by the end of the decade.

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What after 2010

• In B physics beyond 1- 2/ab?
• A lot of measurements but....
• ...........10 36??
• Possibly yes!

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BACKUP
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Towards sin2? B0 ???
Acp