Constraints on from Charmless Two- Body B Decays: Status and
Perspectives James D. Olsen Princeton University Workshop on the
CKM Unitarity Triangle Second Meeting, IPPP Durham April 5-9,
2003
Slide 2
CKM Workshop 2003 J. Olsen 2 Overview is the weak phase
difference between b u tree and b s penguin amplitudes Large
penguin contributions facilitate sensitivity to One physicists
garbage (penguin pollution) is anothers gold! Challenges Strong
phase difficult to calculate Electroweak penguins (EWP)
Rescattering All two-body modes are useful K sensitivity to A( 0 )
~ T, cross-check kinematic assumptions (A CP in 0 ) KK constraints
on rescattering
Slide 3
CKM Workshop 2003 J. Olsen 3 General Strategies Use SU(2)
symmetry Relate decay rates for all K modes (use R ratios of BFs)
Assuming negligible annihilation amplitudes, K 0 pure P Use A CP to
remove dependence on strong phase Provides allowed regions in R vs.
Use a model QCD FA, PQCD, Charming Penguins, etc Pitfalls?
Electroweak penguins (EWP) Can be included; constrained by asmmetry
in Rescattering Use decay rates for KK modes to constrain
rescattering effects
Slide 4
CKM Workshop 2003 J. Olsen 4 Experimental Considerations
Charmless decays are Cabibbo suppressed ( |V ub | 2 ) BF(B KK) ~ 10
-8 - 10 -6, BF(B ) ~ 10 -6, BF(B K ) ~ 10 -5 Background dominated
by At the (4S) can use kinematics and topology to separate
spherical B decays from jetty light-quark production Particle ID is
critical ( /K separation) BaBar Detector of Internally Reflected
Cherenkov Light Belle Aerogel Dominant sources of systematic error
(now) BF: PDF shapes, efficiency A CP : PDF shapes, possible
detector charge bias
Slide 5
CKM Workshop 2003 J. Olsen 5 Data: B K K+-K+- K0+K0+ BaBar
BaBar Belle CLEO 81 78 15 BF(10 -6 )
Slide 6
CKM Workshop 2003 J. Olsen 6 Data: B K K+0K+0 K00K00 Belle
BaBar Belle CLEO 81 78 15
Slide 7
CKM Workshop 2003 J. Olsen 7 Data: B Fit region Belle +-+- 0000
BaBar BaBar Belle CLEO 81 78 15 Br(B 0 Br(B 0 )?
Slide 8
CKM Workshop 2003 J. Olsen 8 Data: B KK K+K-K+K- K+K0K+K0
K0K0K0K0 Belle BaBar PID cross-feed BaBar Belle CLEO 81 78 15 No
sign of B KK
Slide 9
CKM Workshop 2003 J. Olsen 9 Summary of Branching Fractions *
weighted average (speakers calculation) *
Slide 10
CKM Workshop 2003 J. Olsen 10 The penguins are out there If
trees dominate in we would have: Data: first ratio is 0.25 0.08,
second is 2.1 0.4 Destructive P/T interference in Color-suppressed
tree in 0 ? If penguins dominate in K we would have: Data:
Slide 11
CKM Workshop 2003 J. Olsen 11 Constraints on P/T Use data P
from K 0 + Two-body BFs S and C CKM indirect constraint on BaBar
prefers: 0.1 < |P/T| < 0.4 -170 < arg(P/T) < -40 Belle
prefers: 0.5 < |P/T| < 1.1 -70 < arg(P/T) < -30 P/T
Arg(P/T) Belle BaBar P/T
Slide 12
CKM Workshop 2003 J. Olsen 12 Is Rescattering Important? Could
modify branching fractions and CP asymmetries in and K decays,
complicating extraction of and KK decays are more sensitive to
rescattering Could have significant enhancement through (for
example) DD or intermediate states BaBarPQCD * K+K-K+K-