babar status & plans david b. macfarlane slac epac meeting january 25, 2006
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BABAR Status & Plans
David B. MacFarlaneSLAC EPAC MeetingJanuary 25, 2006
Jan 25, 2006 BABAR Status and Plans 2
Pillars of BABAR physics program Highly constrained and redundant set of
precision tests of weak interactions in the Standard Model
Searches for physics beyond the Standard Model in a well understood & characterized environmento Sensitivity to New Physics at LHC mass scales
through rare decays and CP violationo Discovery potential from large data sample across
a whole range of beauty, charm, tau, two-photon, ISR physics
o Full program of flavor physics/CP violation measurements will provide a legacy of fundamental constraints on future New Physics discoveries
Challenging measurements at the edge of sensitivity benefit enormously from operation of both PEP-II &
KEK B Factories
Jan 25, 2006 BABAR Status and Plans 3
The BABAR Collaboration
11 Countries 80 Institutions623 Physicists
Jan 25, 2006 BABAR Status and Plans 4
BABAR & Belle physics results
BABAR Belle
Journal Papers 184 155
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BaBar
Belle
Jan 25, 2006 BABAR Status and Plans 5
Integrated data sample to date
96% efficiency over the entire history of
BABARBABAR, Run 5
Jan 25, 2006 BABAR Status and Plans 6
Parameter Units Design Oct 2005
I+ mA 2140 2940
I- mA 750 1740
Number of bunches
1658 1732
y* mm 15-20 11
Bunch length mm 15 11-12
y 0.030.044-0.065
Luminosity x1033 3.0 10.0
Int lumi / day pb-1 130 727.8
PEP-II overall parameters and goals
More than 3x design
More than 5x design
Jan 25, 2006 BABAR Status and Plans 7
Parameter Units Design Oct 2005 2007 goal
I+ mA 2140 2940 4000
I- mA 750 1740 2200
Number of bunches
1658 1732 1732
y* mm 15-20 11 8-8.5
Bunch length mm 15 11-12 8.5-9
y 0.030.044-0.065
0.054-0.07
Luminosity x1033 3.0 10.0 20
Int lumi / day pb-1 130 727.8 1300
PEP-II overall parameters and goals
30%
40%
10%
Factor 2!
Jan 25, 2006 BABAR Status and Plans 8
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Projected data sample growthIn
teg
rate
d L
um
inosit
y [
fb-1]
12
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Lpeak = 9x1033
o PEP-II: IR-2 vacuum, 2xrf stations, BPM work, feedback systems
o BABAR: LST installation
4-month down for LCLS, PEP-II &
BABAR
Double from 2004 to 2006
ICHEP06
Double again from 2006 to
2008 ICHEP08
Jan 25, 2006 BABAR Status and Plans 9
IFR upgrade with LSTs
Bottom & top sextants installed summer 2004Remaining sextants delayed until fall 2006
Jan 25, 2006 BABAR Status and Plans 10
Weak Interaction in Standard Model
Apex at
,
0 0B - B mixing
) B and ( b c
( ) b u
0,1 0,0
Unitarity Triangle as a summary of Standard Model
b physics
us ubud
cs cbcd
ts tbtd
V V VV V V V
V V V
+ phases
Radiative penguin decays
* * *Unitarity: 0ub cb tbud cd tdV V V V V V
Jan 25, 2006 BABAR Status and Plans 11
Classic indirect constraints
ubV K
dm sm
2008: ~5%
Jan 25, 2006 BABAR Status and Plans 12
Weak Interaction in Standard Model
Apex at
,
0 0B - B mixing
) B and ( b c
( ) b u
0,1 0,0
1
2
3
Unitarity Triangle as a summary of Standard Model
b physics
us ubud
cs cbcd
ts tbtd
V V VV V V V
V V V
+ phases
Radiative penguin decays
CP violation
* * *Unitarity: 0ub cb tbud cd tdV V V V V V
CKM elements & quark masses are fundamental constants
emerging from EW symmetry breaking
Jan 25, 2006 BABAR Status and Plans 13
0 0/ SCPV in B J K
Interference of b c tree decay with mixing
CPV in charmonium modes
0- 0B Bmixing ( )b u
,
)B and ( b c 0,1 0,0
1
2
3
0Bb
db
d t
tWW 0B
0Bc
b
d
W/J
d
c
s 0K
Jan 25, 2006 BABAR Status and Plans 14
0 , , ,
CPV in B
Interference of suppressed b u tree decay with
mixing
CPV in charmless modes
0- 0B Bmixing
( )b u
,
)B and ( b c 0,1 0,0
1
2
3
0Bb
db
d t
tWW 0B
0Bub
d
W
d
u
d
3rd component:
sizable Penguin diagram
0Bu
b
d
W
d
ud
g, ,u c t
Jan 25, 2006 BABAR Status and Plans 15
Remarkably good progress on gamma!
0 , ,CP DCS: CPV in B D K D K
Interference of color-allowed and color-suppressed tree
decays
0- 0B Bmixing
( )b u
,
)B and ( b c 0,1 0,0
1
2
3
Bcb
u
W
(*)0Du
u
s(*)K
Bc
b
u
W(*)0D
u
u
s (*)K
Effect depends on ratio of two diagrams
( ) decay to common fi nal state
D D
0 0, , SCP DCSD D D K
Jan 25, 2006 BABAR Status and Plans 16
Direct CP violation measurements
sin2
cos2
2008: ~2% 2008: 10o
2008: 5-10o
Jan 25, 2006 BABAR Status and Plans 17
UT from sin2 & indirect constraints
Paradigm change!
Now: looking for New Physics as
correction to CKM
Overconstrained: growing set of independent measurements are consistent
with CKM picture
Jan 25, 2006 BABAR Status and Plans 18
UT from CP violation measurements alone
New B Factory milestone:
Comparable UT precision from CPV in B decays alone
Overconstrained: subsets of
measurements can be used to test for
new physics
Jan 25, 2006 BABAR Status and Plans 19
0 0 0 , , S SCPV in B K K
Interference of suppressed b s Penguin decay with
mixing
CPV in Penguin Modes
0- 0B Bmixing ( )b u
,
)B and ( b c 0,1 0,0
1
2
3
0Bb
db
d t
tWW 0B
0Bs
b
d
W
0Kd
ss
g, ,u c t
Another implication of overconstrained:
redundant approaches to same CKM
parameter
Jan 25, 2006 BABAR Status and Plans 20
Potential New Physics contributions
0B
b ss
sd
d
W
g
, ,u c t
“Internal Penguin”
0SK
0B
0SK
0 0 B K
0 0 B K
0SK
0B
b
s
s
sd d
0SK
0B
b
s
s
sd d
SUSY contribution with new phases
New physics in loops?
Jan 25, 2006 BABAR Status and Plans 21
Revealing new physics
LHC
B Factory
Squark mass matrix (d sector)
Jan 25, 2006 BABAR Status and Plans 22
Summary after summer 2005 updates
: 237 million pairsBelle: 386 million pairs
BABAR BBBB
No sign of Direct CP
2.4 between CP violation in s-
penguin vs sin2 (cc)
Summer 05 results
About 0.5 loss vs Winter 2005 due to shift in charmonium average
Charmonium
s-Penguins
Jan 25, 2006 BABAR Status and Plans 23
BABAR CKM physics goalsPhysics Impact FY2006
450 fb-1
FY2007650 fb-1
FY20081000 fb-1
Precision measurement of sin2
Fundamental constant of the SM, whose precision is only limited by statistics
Improve error by factor of two to 2%
Precision measurement of CP asymmetry in penguin modes
Primary approach to new physics in loop decays; presently discrepant with SM predictions at 2.4 level when averaged over all available modes
Potentially reach the 4-5 level for average of all modes
Could reach the 4-5 level for individualtheoretically-clean modes
Precision measurement of unitarity angle
Fundamental constraint on the UT
Discovery of if it has SM branching fraction
Isospin analysis in allows better than 10o measurement
Precision measurement of unitarity angle
Fundamental tree-level constraint on phases and amplitudes originating from any new physics beyond the SM
Pioneering measurements with 10-15o accuracy
Determine to 5-10o precision
Precision measurement of with inclusive & exclusive semileptonc B meson decays
Fundamental tree-level constraint on amplitudes and phases originating from any new physics beyond the SM
Inclusive decays reach 6.5% precision
Exclusive decays reach 8% precision
b sqqb sss
b sss
0 0 0B B
ubV
Jan 25, 2006 BABAR Status and Plans 24
Global CKM fit: 2008
( ) 6.5% ubV ( ) 5%sm (sin 2 ) 0.019 o( ) 8 o( ) 10
95% contours
Jan 25, 2006 BABAR Status and Plans 25
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0.40Jan-03
Jul-03
Jan-04
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Jul-09
Err
or
on
sin
e am
pli
tud
eProjections to summer 2008
K*
5 discovery region if non-SM physics is 0.30 effect
2004=240 fb-1
2008=1.0 ab-1
Golden modes reach 5
sigma level
Projections are statistical errors only; but systematic errors at few percent
level
Luminosity expectation
s:
20082004
( ) 0.30S
f0KS
KS0
KS
’KS
KKKS
Jan 25, 2006 BABAR Status and Plans 26
now
( ) 6.5% ubV
2008
UT constraints in 2008
Assumption: no NP in trees [almost any NP model]
95% contours
Significant constraint on all New Physics models in LHC era
( ) 8% ubV
Jan 25, 2006 BABAR Status and Plans 27
Bounds on new physics in Bd mixing
now
2008
Model independent
Mass scale being probed
for unit coupling:
(now) ~ 5 TeV(2008) ~
10TeV
0/ sin2
d d d
d
SM
B B B
S BCP
M C M
A J K
Introduce new physics in mixing
diagram
Jan 25, 2006 BABAR Status and Plans 28
BABAR rare decay physics goals
Physics Impact FY2006450 fb-1
FY2007650 fb-1
FY20081000 fb-1
Discovery of Provides a determination of and constrains Higgs sector in MSSM and NP in a parameter regime that is complementary to LHC
Limit First hints Discovery if it has SM branching fraction
Precision determination of branching fraction, CP asymmetry, and photon energy spectrum
Loop diagram that provides unique insight into B meson structure and constrains Higgs sector in MSSM and NP in a parameter regime that is complementary to LHC
Ultimate precision on photon energy spectrum
Strong constraints from 5% error on BF; 1-2% error on CP asymmetry
Precision determination of branching fractions, CP and FB asymmetries
Contributions from Z-penguin and W-exchange loops that give additional constraints on MSSM and NP in a parameter regime that is complementary to LHC
Useful precision for constraints on NP
Strong constraint for NP from BF, CP and FB asymmetries
Discovery of Provides a unique determination of CKM matrix elements ; likely before mixing discovery
First hints Discovery if it has SM branching fraction
Precise measurement of BF
b s
b s
ubVB
B
/td tsV V0 0-S SB B
Jan 25, 2006 BABAR Status and Plans 29
New CKM constraints in sight
B
B
b
W
td
W,H
b
u
2008: Possible discovery Possible discovery: 2007
Jan 25, 2006 BABAR Status and Plans 30
Complementarity with LHC
today
2008
Approx…
2HDM
Constraints from B , B s
Jan 25, 2006 BABAR Status and Plans 31
BABAR Physics GoalsPhysics Impact FY2006
450 fb-1
FY2007650 fb-1
FY20081000 fb-1
Search for mixing
Highly suppressed in the SM and therefore an ideal place to search for new physics in charm mixing diagram
Hint if 1% mixing amplitude
Discovery if 1% mixing amplitude
Search for lepton-flavor violation in or other tau decays
Expected to be significantly enhanced in many extensions of the SM accommodating neutrino mass, but extremely small in the SM itself
Limits reach 2x10-8 sensitivity
New discovery in heavy hadron spectroscopy
Improved understanding of QCD in non-perturbative regime
Discoveries possible anytime
Discoveries possible anytime
Discoveries possible anytime
0 0-D D
Jan 25, 2006 BABAR Status and Plans 32
Lepton-flavor violation & mSUGRA
tan= 55Inverted hierarchy
s- i
s LS
P
allo
we
d
Br(e) < 1x10-8
2x10-85x10-8
11x10-8
Current BABAR limit
2008 limit
Jan 25, 2006 BABAR Status and Plans 33
Summary: Physics plans for BABAR Goal for 2005-2006: double current data set
o Delay in Run 5 can be overcome by summer 2006 with extended running period, with substantial reduction in errors on CP violation asymmetries in rare decay modes
o Error on average of Penguin modes should reach 0.06 Goal for 2007-2008: double again to ~1 ab-1
o Individual Penguin modes with errors in range 0.06-0.12o Suite of fundamental Standard Model measurements with
substantially improved levels of precision
Beyond 2008 might offer exciting opportunities if New Physics has been seen by B Factories & LHC
o Sensitivity to New Physics through rare decays, CP violation, & large data sample with a significant discovery potential
o Full program of flavor physics/CP violation measurements provide fundamental constraints on future New Physics discoveries
Backup Slides
Jan 25, 2006 BABAR Status and Plans 35
A day in the life of a B Factory
Jan 25, 2006 BABAR Status and Plans 36
Peak PEP-II Luminosity (x1E33) per Month
0
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n-99
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PEP-II performance: peak luminosity
Jan 25, 2006 BABAR Status and Plans 37
BABAR Detector
DIRC PID)144 quartz
bars11000 PMs
1.5T solenoid
EMC6580 CsI(Tl) crystals
Drift Chamber40 layers
Instrumented Flux Return
Iron / Resistive Plate Chambers or Limited
Streamer Tubes (muon / neutral hadrons)
Silicon Vertex Tracker
5 layers, double sided strips
e
(3.1GeV)
e (9GeV)
Collaboration founded in 1993Detector commissioned in 1999
Jan 25, 2006 BABAR Status and Plans 38
DCH electronics upgrade Motivation:
o Remove anticipated deadtime problem due to serialization and shipping of data from DCH to readout module
Upgrade in two steps:o Phase 1 (summer 2004): L1 to
~4kHz• Reduce ADC payload (3216
bytes) from front ends with no impact on dE/dx performance
o Phase 2 (Oct 2005) : L1 to ~5kHz• Larger FPGA to allow feature
extraction on DCH endplate• New boards installed in Oct
down, ready to activate FPGA code
Jan 25, 2006 BABAR Status and Plans 39