1. David B. MacFarlane SLAC EPAC Meeting January 25, 2006
BABAR Status & Plans
David B. MacFarlane
SLAC EPAC Meeting
January 25, 2006

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 environment
Full program of flavor physics/CP violation measurements will provide a legacy of fundamental constraints on future New Physics discoveries
Sensitivity to New Physics at LHC mass scales through rare decays and CP violation
Discovery potential from large data sample across a whole range of beauty, charm, tau, two-photon, ISR physics
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. PEP-II overall parameters and goals
Units
Design
Oct 2005 I+ mA
2140
2940 I-
750
1740
Number of bunches
1658
1732
by* mm
15-20 11
Bunch length 15
11-12 xy
0.03
Luminosity
x1033
3.0
10.0
Int lumi / day
pb-1
130
727.8
More than 3x design
More than 5x design
Jan 25, 2006
BABAR Status and Plans

4. Weak Interaction in Standard Model
+ phases
Unitarity Triangle as a summary of Standard Model b physics
Jan 25, 2006
BABAR Status and Plans

5. Weak Interaction in Standard Model
+ phases
Unitarity Triangle as a summary of Standard Model b physics
CKM elements & quark masses are fundamental constants emerging from EW symmetry breaking
CP violation
Jan 25, 2006
BABAR Status and Plans

6. CPV in charmonium modes
Interference of b ® c tree decay with mixing
Jan 25, 2006
BABAR Status and Plans

7. 3rd component: sizable Penguin diagram
CPV in charmless modes
3rd component: sizable Penguin diagram
Interference of suppressed
b ® u tree decay with mixing
Jan 25, 2006
BABAR Status and Plans

8. Remarkably good progress on gamma!
Effect depends on ratio of two diagrams
Suppressed
Interference of color-allowed and color-suppressed tree decays
Jan 25, 2006
BABAR Status and Plans

9. UT from sin2b & indirect constraints
Overconstrained: growing set of independent measurements are consistent with CKM picture
Now: looking for New Physics as correction to CKM
Paradigm change!
Jan 25, 2006
BABAR Status and Plans

10. 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

11. Interference of suppressed b ® s Penguin decay with mixing
CPV in Penguin Modes
Another implication of overconstrained: redundant approaches to same CKM parameter
Interference of suppressed
b ® s Penguin decay with mixing
Jan 25, 2006
BABAR Status and Plans

12. Potential New Physics contributions
SUSY contribution with new phases
New physics in loops?
“Internal Penguin”
Jan 25, 2006
BABAR Status and Plans

13. Squark mass matrix (d sector)
Revealing new physics
B Factory
LHC
Squark mass matrix (d sector)
Jan 25, 2006
BABAR Status and Plans

14. Summary after summer 2005 updates
Charmonium
s-Penguins
Summer 05 results
2.4s between CP violation in s-penguin vs sin2b (cc)
No sign of Direct CP
About 0.5s loss vs Winter 2005 due to shift in charmonium average
Jan 25, 2006
BABAR Status and Plans

15. BABAR CKM physics goals
Impact
FY2006
450 fb-1
FY2007
650 fb-1
FY2008
1000 fb-1
Precision measurement of sin2b
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 2.4s level when averaged over all available modes
Potentially reach the 4-5s level for average of all
modes
Could reach the 4-5s level for individual
theoretically-clean modes
Precision measurement of unitarity angle a
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 g
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
Jan 25, 2006
BABAR Status and Plans

16. Global CKM fit: 2008
95% contours
Jan 25, 2006
BABAR Status and Plans

17. Summary: Physics plans for BABAR
Goal for : double current data set
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
Error on average of Penguin modes should reach 0.06
Goal for : double again to ~1 ab-1
Individual Penguin modes with errors in range
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
Sensitivity to New Physics through rare decays, CP violation, & large data sample with a significant discovery potential
Full program of flavor physics/CP violation measurements provide fundamental constraints on future New Physics discoveries
Jan 25, 2006
BABAR Status and Plans