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SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 1
BABAR Status and Outlook
BABAR Status and Outlook
Marcello A. Giorgi
on behalf of BaBar Collaboration
EPAC meeting - SLAC
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 2
BABAR
DCH
EMC
DIRC
COIL
IFR
SVT
The The BBAABBARAR CollaborationCollaboration
10 Countries 75 Institutions 579 Physicists
Canada China France Germany Italy The Netherlands Norway Russia United Kingdom USA
[4/18] [1/5] [5/55] [3/30] [11/101] [1/2] [1/3] [1/9] [10/66] [38/290]
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 3
New environment: high luminosity asymmetric collider
1)Search for CP violation in B meson 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 has been established by BaBar and Belle
TRY to open windows on new Physics beyond Standard Model
More precise CKM measurements, Rare B decays, Charm study, Tau rare decays .
BaBar Physics GOALS
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 4
CP in Standard Model
CKM quark mixing matrix
2
2 4
3
23
2
( )
(
11
21
1 ( )2
11 )
ud us ub
cd cs cb
td ts tb
A iV V V
V V V V A O
V V VAA i
bulB() l
CP Violating phase
BD(*)lbcl
B() B0 Mixing
Unitarity
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 5
Experimental ingredients: BaBar optimized for time dependent CP
asymmetries
+e-e
z
Brec
Btag 4s
(4S) = 0.55
Coherent BB pair
B0
B0
Start the Clock
zc
zt
1
Tag vertex reconstructio
n
Tag vertex reconstructio
n
FlavorTaggingFlavor
Tagging
Exclusive B Meson and Vertex Reconstruction
Exclusive B Meson and Vertex Reconstruction
0sK
J/
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 6
Time dependent rate,flavor mixing and CP,T,CPT
Time dependent rate:dN exp(–|t|/B) ( 1 ± D (S sin(mt) - Ccos(mt)) ) R
2
2
21
1
1
Im2
CS
CPV in Mixing -DecayCPV direct
cp
cp
cp A
A
p
q___
D is the mis-tag dilution
R is the time resolution
0B
0B
CPfCP
mix
ing decay
CPfA
CPfA
t
2
22
im
iMz
z0 CP & CPT violation
1p
q CP and T Violation in mixing
42
2
105sin41 t
c
m
m
p
qSM
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 7
Fit without the “usual assumptions”!Fit BCP and B0flavor eigenstates (/, q/p, z and CP left FREE)
sgn(Re ) 0.008 0.037(stat.) 0.018(syst.) [ 0.084,0.068]
1.029 0.013(stat.) 0.011(syst.) [1.001,1.057]
(Re ) Re 0.014 0.035(stat.) 0.034(syst.) [ 0.072,0.101]
Im 0.038 0.029(stat.) 0.025(syst.
CP
CP CP
q p
z
z
) [ 0.028,0.104]
90% C.L.
The “usual assumptions”work!
Direct limit on Test of CPT invariance Indirect CP in mixing
Preliminary
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 8
LOOK for N.P. in Loops?
from charmonium channelsResults are so far CKM
compatible but…
s
s
s
d
KS
s
s
s
dsin(2) = 0.741 ± 0.067stat ± 0.033syst
?
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 9
B0 +- sin2eff
With incomplete information on Penguin contamination:• Measure S and Cfrom
both sinmt and cosmt terms .
• Compare with predicted S and Cvalues for given , , |P/T|, and . Assume for instance:
From sin2eff to sin2?
isospin analysis, needs B0
22
3021
28.0/
26
)97(
TP
cf. Gronau and Rosner, Phys. Rev. D65, 093012 (2002)
BABAR
Belle 1
Belle 2
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 10
B0 ) the CP fit• Time integrated direct CP:
• Time dependent CP:
• Asymmetry between rates:
08.017.028.0 KCPA
03.008.018.0 CPA
04.018.036.0 C
03.024.019.0 S
03.00.250.15 S
04.00.28 0.180.19-
C
First step towards in B. Full Dalitz analysis in progress.
Preliminary
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 11
Toward : the BD0CP K approach
sin2 from the triangles (Gronau-Wyler method):
BaBar measurements:
2
DD
:seigenstate CP are Dwhere00
CP
0CP
D
)(2 0 KDBA CP
)(2 0 KDBA CP
)%20.035.031.8()(
)(0
0
DBBF
KDBBFR
)%5.06.18.8()()(
)()(00
00
CPCP
CPCP
CP DBBFDBBF
KDBBFKDBBFR
06.017.006.0)()(
)()(00
00
KDBBFKDBBF
KDBBFKDBBFA
CPCP
CPCP
CP
Preliminary
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 12
|Vub| from fully tagged SL decays
Brecoil
BrecoD(*)
Y(4S) l
Xu
Recoil of fully reconstruted B (~4KB /fb-1)
bul signal:MX (< MD)( ~ 60-80%)
S/B 1.7: good!
Preliminary
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 13
Rare B decays
b u : tree, CKM suppressed
b s,d: Radiative (QCD, EM, EW) Penguins FCNC
Leptonic decays: B0 l+l-, B , B l+, …
tree
QCDpenguin
EMpenguin
EWpenguin
probes b inside B
Possible New Physicssignatures: rates and phasesfrom virtual particlesin the loops
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 14
Not only B Physics in BABAR !
A new state decaying into D+s(1970) and 0
has been discovered by us and recently confirmed by CLEO!
D+s 0
D+sK+K- + D+
sK+K- + 0
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 15
An example: D mixingVery small in the S.M. 2 additional suppression
A window for new physics
Charm, tau discovery potential
limit3
005.0 222
SU
mmm Wds
lepton number is violated inmany extensions of the S.M.(present limits, O(10-6) are not far from some model predictions)
D0
c
c
u
ud,s d,s
W-
W+
Vcd,cs
V*cd,csV*
ud,us
Vud,us
D0
“long distance” -iy
“short distance” x
D0 D0
K-,
K+,+
Another example: lepton flavour violation
S.M., extended to include mixing and mass:
BR( O(10 - 34)
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 16
Luminosity: Present and Future
FY2002
FY2003
Longerterm
So far in Run 3: On peak 30.02 fb-1
Off peak 2.57 fb-1
By the end of the decade: 12 ab-1
Summer 2002 and Winter 2003:Run 1 + Run 2On peak 83.9 fb-1
Off peak 9.6 fb-1
92 M BB pairs
Summer 2003:Run 3add 40 fb-1
By end 2006: 500 fb-1
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 17
Next about sin2• Extrapolated statistical and systematic uncertainties
Statistical uncertainty Golden modes
Param. Channel (stat)/(syst) 0.08 ab-1
(stat)/(syst) 0.5 ab-1
(stat)/(syst) 2.0 ab-1
sin2 Im(+) S S S
J/KS Golden D*D* J/0 KS ’ KS
0.08 / 0.03 0.07 / 0.03 0.43 / 0.13 0.49 / 0.16 0.50 / 0.09 0.34 / 0.03
0.037 / 0.018 0.031 / 0.018 0.16 / 0.07 0.20 / 0.20 / 0.14 /
0.018 / 0.018 0.015 / 0.018 0.08 / 0.03 0.10 / 0.10 / 0.07 /
21 L
1syststat ab2at L
(*)
(*) This syst error of 0.018 is dominated by DCS decays of charm in K tagged events. Lepton tag is not affected !
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 18
What next for Sin 2
Pure penguin process B Ks
The present value with 80 /fb is:
S=sin2=-0.19-0.50+0.52 stat.±0.09syst.
With 2/ab (S) goes down to 0.1
But also B ’ K and B K K K
NEW PHYSICS ?
New quanta in the loop?
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 19
Results (0.08 ab-1) for BFactories
Param. Channel (stat)/(syst) 0.08 ab-1
(stat)/(syst) 0.5 ab-1
(stat)/(syst) 2.0 ab-1
S C
+-
0.34 / 0.05 0.25 / 0.04
0.12 / 0.03 0.10 / 0.03
0.06 / 0.05 /
Extapolations for sin2eff
Extrapolated errors (BaBar)
Param. BaBar Belle S C
0.02 0.34 0.05 -0.30 0.25 0.04
-1.23 0.41 (+ 0.05-0.07) -0.77 0.27 0.08
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 20
r=0.2 (2ab-1), sin2fit: sin2
from B-D0(CP)K-: projections
Recent experimental results (BaBar)
Toy MC projections: (Fit unreliable for r = 0.1)
02.029.002.1)(
)(
0
11
KDB
KDBn
)02.026.072.0()(
)(
0
11
KDB
KDBp
r=0.3 (0.5 ab-1), sin2fitsin2
08.023.017.0 CPA
ACP=0.174 0.031
r=0.2 =60o =30o
(2ab-1)
KKD0500
)1.0(
)(
)(
0
0
O
KDBA
KDBAr
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 21
projected errors for |Vub|
Selection:One B reconstructed in D(*)XLepton momentum and neutrino massKaon veto, charge balanceFit Mx with constraints
MX distribution fit:
bul, bcl, backgroundErrors:
Statistical L(ab-1) = 0.08 0.5 2.0 10 stat(%) = 7.0 2.8 1.4 0.6
Experim. Systematic ~5% (now) 2.5% (bcl bkgd)
Theoretical ~ 9% ((mb)=90MeV) 5% (b ulabove cut)
Mx (GeV)
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 22
B beam method
“B – beam”
BrecoD(*)
Y(4S) l
h
B factories present an unique peculiarity. Events are pure B B and a full reconstruction of one side allow to treat the other as a pseudo B-beam. The study of rare decays with neutrinos are becoming possible with very high integrated luminosity.
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 23
Integrated luminosity vs physics
2sin
1 abLdt1.0 0.1 .105.0 0.2
BaBar2006 2009 ?
cbub VV 2sin2sin llKllX s
*, *, KX s
,
2002
Continuous improvement
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 24
Some comments about comparison with Hadron machine expts.
CKM parameters BABAR/Belle BTeV/LHC-B 2 ab-1 107 s
Sin(charmonium) 0.015stat/0.018syst 0.025/0.014Sin (penguins bsss) 0.10 stat ----in S eff(B0 0.06 stat 0.024/0.056
eff – ( B0 ) <10° ----Sin() (B0 D* ) 0.15 ---- (B DK) 7° <10°/<19°|Vub| 1.4%+ Th. Unc.(now better 10%) ----
Of course Bs mixing and decay can be studied well at hadron machines ( and a lot of good physics from Bs)
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 25
Rare decays - SummaryChannel BF BTeV/LHC-B (107 s) BABAR/BELLE (2 ab-1)
bs 3.3±0.3 10-4 ---- 44.0K 6.8K(Btagged)
BK*10-5 25K 24.0KB ()10-6 ---- 1.2K
bs±1.5 10-6 3.6K 1.2Kbse+e- 1.4KBK*±1 10-6 2.2K/4.5K 0.5KBK*e+e- 0.6K
bs±0.9 10-5 ---- 30BK*10-6 ---- 6
B10-5 ---- 70B10-735
Limit< 10-8
Bfactory and hadron machine measurements are complementary !
Rates…Fully
reconstructed B on the other side are used
The so called
B beam option
Asymmetries!
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 26
What about Detector? SVT!BABAR is a VERY good detector: very difficult to improve it!! (On IFR barrel is the only major intervention needed)
SVT is 98% efficient. No degradation due to irradiation has been observed so far
SVT so far tested for rad hardness up to 4 Mrad (OK!) rad tests are going on.
Partial SVT replacement is considered by 2005. Almost 50% of modules built as spare.
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 27
Instrumented Flux Return• Instrumented Flux Return
– 2000 m2– 342 barrel RPCs– 432 endcap RPCs– 32 cylindrical RPCs
• Electronics– 3300 Front end cards
• ~ 40 mV threshold• 16 channels connected to
alternate strips
• Gas– 35% Freon 134a, 4.5%
iso-butane, 60.5% Argon
– 1-3 volume changes/day• High Voltage
– > 50 10 kV HV pods
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 28
BABAR RPC• Operates in limited streamer mode• Parallel high resistivity plates
(Bakelite 1011 -1012 cm )• Graphite ~100 k/ • RPCs were filled 3 times with a
mixture of 70% linseed oil and 30% n-pentane and dried by air for several days.
• Changes from L3 RPCs– Polycarbonate buttons with lip
replaced G10 cylindrical button– Thicker oil layer– Single layer with strips on both
sides– No mechanical envelope– Nonflammable gas - low iso-
butane %, CBrF3 replaced by Freon 134a C2H2F4
Efficiency of barrel RPCs after production ~97%
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 29
1999• IFR complete May 99 • RPC efficiencies good• Warning signs
– Some RPCs with > 100 mA were disconnected
• With collision data– HV current limitations force
reduction in # of RPCs• Average Efficiency low
~85%• Barrel is about 50% of total IFR
coverage• Forward Endcap about 40%• Decision was taken in 2000 to
upgrade the Forward Endcap with new RPC (higher QA/QC level) and with more absorber.
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 30
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 from nov 2002
Terminology: 19 slots and 15 RPC layers
RPC belt
Slot18/195 brass layers(slot 8,10,12,14,16)
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 31
RPC problems (post mortem photo)
Gas inlet Debris
Whiskers
Excess oil
Opposite side
Linseed oil – uncured oils move under HV and warm temperatures
Graphite layer develops high resistance
Internal debris and whiskers
5% of barrel has HV problems before New HV distribution
~50% of the barrel modules leak (many have normal efficiency)
Front End electronics problems
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 32
IFR Barrel Upgrade
Muon selectors losing efficiencyA committee was setup in september 2002 to evaluate physics motivation for a IFR upgrade and technology.B.Ratcliff and C.Hearty were chairing the committee.After 3 months the committee Presented its recommendations to BaBar.
Many RPCs die since 1999. Fraction effectively dead is now almost 40%
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 33
Committee proposes to increase the thickness of the absorber and to replace the bakelite RPC with a more robust detector (Limited StreamerTube).
INSTALLATION in 2004 & 2005
We have submitted a proposal and ask for your approval .
FINAL DOCUMENT May22,2003
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 34
SummaryBabar apparatus is generally very robust and can cope
with high luminosity environment above 10 34 . Decision has been taken to upgrade the IFR Barrel with a different technology well established and robust (LST).
Preliminary measurements of pure penguin processes for sin2, measurements of Vub, B->DK, B->includingDalitz plot analysis.
FUTURE – In 2005 complete the installation of the IFR Barrel. Install the Spare modules of SVT, to replace the heavily irradiated modules on horizontal plane.
Approach the precision measurement with 0.5/ab of integrated luminosity . Towards more than 1.0/ab explore possible openings for new physics.Study of CP asymmetries but also rare decays in b, c and tau sectors.
Profit from full reconstruction of one B : “ Pseudo B beam”
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 35
BACKUP SLIDES
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 36
Flavour mixing and CP,T,CPT
m=mH-m L 2|M12| 0.5ps-
1
1/ 1.6 ps
=H-L |M12|Re (12/M12)
SM
1p
q CP and T Violation in mixing
42
2
105sin41 t
c
m
m
p
q
As in K sector where k=(p-q)/(p+q) ~O(10-3)
SM
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 37
Flavour mixing and CP,T,CPTCP an CPT conservation if H11=H22
2
22
im
iMz
2
2211 MMM
2
2211
t)),BB((Probt)),BB((Prob_
0_
000
0z
CP and CPT VIOLATION
Assumptions made in the usual sin2 analysis:0H L
12 122
12 122
1i
i
Mq
p M
11 22 11 222
2
( )0
i
i
M Mz
m
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 38
Time Dependent CP asymmetries
CP eigenvalueMi
tdtb
tdtb eVV
VV
p
q 2
*
*
Amplitude ratio B0fcp/B0fcp
B mixing
Measured from data (Flavour sample)!
D mis-tag dilutionR time resolution
CPV in mixing-decay interference direct CPV
dN exp(–|t|/B) ( 1 ± D (S sin(mt) - C cos(mt)) ) R
2
2
21
1
1
2
CS
Flavour tag
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 39
Search for B+ +
B candidate Semileptonic tagD0
Y(4S)
cosB,Dlfor B D0X tags
Total signal-side neutral energy
Semileptonic tags: BF(B+ +) < 4.910-4 (90% CL)Fully reco tags: BF(B+ + ) < 7.710-4 (90% CL)
combined: < 4.1 10-4
Preliminary
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 40
RPC efficiency 00
-1.4% /month
-1.4% /month
-0.56%/month
Gas change
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 41
Detector studies• Realization that the RPC
efficiencies did not recover after cooling spurred detector studies– Efficiency was computed as a
function of position
• Limited tests were carried out during accesses or on a few chambers– Lowered barrel temp. to 17 C. – Reversed HV– Increased gas flow– Lowered discriminator threshold– Put weights over inefficient regions
• No effect• Gas composition was regularly
tested– No evidence of water vapor
A wide spread of plateau curves were measured.
SLAC 06/12/03 EPAC meeting
Marcello A. Giorgi 42
RPC radiography The RPC efficiency was mapped in 2D showing irregular regions of reduced efficiency.
D. Piccolo
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Marcello A. Giorgi 43
Occupancy plots for run 38637
Brick shields ~.8 m from L 16