1. Search for Super-Penguins: CP Violation in B0->K+K-K0
D. Dujmic, SLAC
For BABAR Collaboration SM
rules
Special thanks to: G. Cavoto, M. Krishnamurthy, E. Di Marco, M.Pierini, A.Roodman, S.Spanier, J.Thompson
Sep 11, 2006
SLUO Anual Meeting 2006

2. CP Violation in SM ? CKM picture of charged weak currents: p=u,c,t W ±
(solely responsible for CPV in SM)
p=u,c,t
q=d’,s’,b’
W ±
Vpq ?
But amount of CP violation too small:
- observation:
- area of unitarity triangle:
Additional sources of CP violation needed
Sep 11, 2006
SLUO Anual Meeting 2006

3. Search for Super-Penguins
Penguin amplitude in SM
Super-penguin, beyond-SM?
Example of SUSY diagram SM
rules
Double-CKM suppression:
Loop suppression:
Decay rates small BF<7·10-5
Virtual, heavy particles can appear in loops
- can be relatively large, O(1)
- in general not CP-conserving
Sep 11, 2006
SLUO Anual Meeting 2006

4. CPV Parameter sin2b  B0  K+K-K0 amplitudes: CPAsymmetry: IF:
flavor
K+K-K0
B0  K+K-K0 amplitudes:
tag e- 
Interference term has different signs for B0/B0bar tags
Interference phase only due to B0/B0bar mixing (in SM) SM
CPAsymmetry:
(B0/B0bar tags)
super
penguins ~0
same asymmetry
for J/YKS and K+K-KS
IF: or
super-penguins exist!
Sep 11, 2006
SLUO Anual Meeting 2006

5. Estimate of Dsin2b in K+K-KS
Tree
From tree-dominated decays
B0->J/yKS (SM reference point):
Penguin
Experimental average of all penguins
(penguin-tree)
Sep 11, 2006
SLUO Anual Meeting 2006

6. Analysis of 3-Body Decay
Selection of charm-less 3-body decays is tricky
- large background requires usage of several kinematic, event-shape variables in event selection
- good particle ID
CP Violation measurement with additional complication
- CP depends on angular momentum L between K+ and K-
- (K+ K-)KS can be both CP-even and CP-odd * K+ K- B0 KS L
L’=L
L=even
CP(K+K-KS)= +1
-sin2b
L=odd
CP(K+K-KS) = -1
+sin2b
Dilution if
both CP present!!
-> (2fodd-1) sin2b
How to analyze angular momentum composition?
*[ CP(KKKS)= - CP(KKKL) ]
Sep 11, 2006
SLUO Anual Meeting 2006

7. Need Dalitz plot analysis to measure CP asymmetry
CP Content
Fractions of P-wave from analysis of angular moments:
0.29 ± 0.03 over whole DP
0.89 ± 0.01 in f(1020) region
BABAR-CONF-06/40 (ICHEP06)
P-wave
strength
Fraction of P-wave
From 879±36
K+K-KS(p+p-) decays
From 624±30
K+K+K- decays
previously:
- cut >1.1GeV (assume CP-even)
<m< (assume CP-odd)
Need Dalitz plot analysis to measure CP asymmetry
Sep 11, 2006
SLUO Anual Meeting 2006

8. B0→K+K-K0 Isobar Model fK0 f0(980)K0 X0(1550)K0 Non-resonant
Component CP
fK0
odd
f0(980)K0
even
X0(1550)K0
Nonresonant
even(90%)
odd(10%)
cc0K0
toy Dalitz plot
fK0
f0(980)K0
X0(1550)K0
Non-resonant
Charm(onium) contributions:
D-K+, DS-K+
cc0K0
Use flavor-symmetry to relate
BABAR’s K+K+K- Dalitz plot
Sep 11, 2006
SLUO Anual Meeting 2006

9. Dalitz Plot PDF Measure CP asymmetry in time-dependent Dalitz plot:
Five observables: Dt, s(Dt), m(K+K-), cosqH, tag flavor
B0 amplitude
B0bar amplitude
CP Violation: Rate difference
Phase difference
Sep 11, 2006
SLUO Anual Meeting 2006

10. … Add All K+K-K0 Final States
K+K-KS(p+p-)
138 ± 17
K+K-KS(p0p0)
f(1020)
879 ± 36
“X0(1550)”
Non-resonant
cc0
f0(980)
K+K-KL
499 ± 52
Add K+K-KS(KSp0p0) and K+K-KL
All channels use same Dalitz plot model!
~1500 signal events
Sep 11, 2006
SLUO Anual Meeting 2006

11. Average CP-Asymmetry Combine KKKS+-, KKKS00, and KKKL KKKS+- alone:
Assume same CPV parameters for all KKK0
KKKS+- alone:
SM:
ACP=0
b=0.370
Component
Fraction (%)
fK0
12.9±1.3
f0(980)K0
22.3±8.9
X0(1550)K0
4.1±1.8
Nonresonant
91±19
cc0K0
2.8±0.8
D-K+, DS-K+
4.9±1.1
Sep 11, 2006
SLUO Anual Meeting 2006

12. Measurement of b
Assume final state is mixture of CP-eigenstates (partial waves)
both real and imaginary b/c of CP-even, -odd interferences (->2b)
real in Q2B analyses (->sin2b)
p/2-beff
p/2-beff
beff
4.6s
Sep 11, 2006
SLUO Anual Meeting 2006

13. CPV in Low K+K- Mass Resonant fractions for m(K+K-)<1.1GeV
f(1020)K0
57%
f0(980)K0
34%
Non-res
13%
Low-K+K- mass fit for CPV parameters in fK0 and f0K0 to reduce dependence on Dalitz plot model
fK0 theoretically very clean s(sin2b)~ O(1%)
Fix S-wave, float isobar parameters for P-wave
KKKs+-
252 ± 19
KKKs00
35 ± 9
KKKL
195 ± 33
Sep 11, 2006
SLUO Anual Meeting 2006

14. CPV in Low K+K- Mass Combined KKKS+-, KKKS00, and KKKL fKS ACP=0
asymmetry plot ±15MeV under f
fKS
SM:
ACP=0
b=0.370
f0KS
CPV measurements in f0Ks and fKs correlated (one background for the other)
cross-check with Q2B analysis
syst. errors dominated by Dalitz plot model
consistent with SM, Belle
Sep 11, 2006
SLUO Anual Meeting 2006

15. Summary
Time-dependent Dalitz plot analysis opens new possibilities in study of penguin decays:
- measurement of asymmetry angle (instead of sine of the angle)
- removes dilution for final states with opposite CP
- model uncertainties included in fit
BABAR (bsin2b)
Belle (sin2b)
KKK0
0.661 ±0.12 ± 0.06
(all KKK0)
0.68 ±0.15 ± −0.13
(excluding fKS, KKKS only)
fK0
0.12 ±0.31 ±0.10
0.50 ±0.21 ±0.06
f0(KK)K0
0.31± 0.32 ± 0.07
No result (f0K+K-)
Lower sin2b than expected consistent with trend seen in other analyses
CPV results from penguin decays still intriguing, but need to work harder to observe new phenomena
Sep 11, 2006
SLUO Anual Meeting 2006

16. More Slides
Sep 11, 2006
SLUO Anual Meeting 2006

17. Angular Moments K+ KS K-
- Model-independent approach to extract CP content [BABAR, PRD71,091102]
- Assume S and P-waves decaying into K+K-
K+K- CMS
- Decay rate in terms of moments of Legendre polynomials:
S-wave
- Moments <PL> computed using sPlots
[Pivk, Le Diberder, Nucl.Inst.Meth. A555]
- Fraction of P-wave:
P-wave
(angular momentum conservation)
Sep 11, 2006
SLUO Anual Meeting 2006

18. BABAR/Belle 2006: B0  KKKS Belle BABAR Belle’s estimate (±10MeV):
Belle’s helicity plot
(±10MeV under f mass)
[Hazumi ICHEP06 talk]
B+K+K+K- (230MBB) PRD72,032003(2006)
non-zero yield below and above f peak!
B0K+K-K0 (347MBB)
(bkg substracted)
hep-ex/
Belle’s estimate (±10MeV):
K+K+K- Dalitz (140 fb-1) ~2.75±0.14%
ignores f0(980)
Estimates from BABAR results (±10MeV):
K+K+K- moments (347MBB): ~8±1%
K+K-K0 Dalitz (347MBB) and K+K+K- Dalitz (230MBB): f0K~10±3%, NR~3±1% -> 13±3%
Belle’s fitting range
Old BABAR fitting range
Sep 11, 2006
SLUO Anual Meeting 2006

19. Dalitz Plot Isobar Model
“Non-resonant” i j k
“resonant” i k
Decay
amplitude 
∑res =
{ij}res B j B
Resonant amplitude:
Blatt-Weisskopf form factors
Breit-Wigner
Angular correlations
Coupled channel BW (Flatté)
Single channel BW
Sep 11, 2006
SLUO Anual Meeting 2006