1. How charm data may help for φ3 measurement at B-factories
ВД в эксперименте по измерению масс
25 мая 2002
How charm data may help for φ3 measurement at B-factories
Alex Bondar (BINP, Novosibirsk)
BELLE collaboration
Short description of the method
First results from Belle
Model uncertainties of the method
Model-independent approach using CP-tagged data from Charm Factories
Conclusion
January 13, 2004
φ3 with BD0K Dalitz analysis
А. Полуэктов

2. φ3 with BD0K Dalitz analysis
KEKB & BELLE
BELLE detector
KEKB Collider
3.5GeV e+ & 8GeV e- Asymmetric Collider
3km circumference, 11mrad crossing angle
L = 1.06 x 1034 cm–2s–1 (world record)
Ldt = 158
(140fb-1 : 1.52 x )
~350 scientists, 55 institutions
January 13, 2004
φ3 with BD0K Dalitz analysis

3. The Weak Decays of Quarks
Coupling strength at decay vertex : GFVij
universal Fermi weak coupling : GF
Vij : quark-mixing matrix elements
CKM matrix :
unitarity : Vji*Vjk=dik
explicit parametrization (Wolfenstein)
complex phase leads to different bu and td amplitudes for quarks and anti-quarks.
quark decay
GFVij i j
GFVij* CP
l = ± A = 0.81± |r-ih| = 0.36±0.09
|1-r-ih| = 0.79±0.19
January 13, 2004
φ3 with BD0K Dalitz analysis

4. φ3 with BD0K Dalitz analysis
The B Unitarity Triangle
Using relation - -
(r,h)
(a)
(b)
(g)
B0 pp
B0 rp
B0 D(*)p
B+ DK
B0 J/yKs
B0 fKs
B0 D(*)D(*)
January 13, 2004
φ3 with BD0K Dalitz analysis

5. φ3 with BD0K Dalitz analysis
f3 measurements
bu(cs) & bc(us) interference : B-DK- decays
GLW method : use CP eigenstates of D0 meson (DCP)
ADS method : use K+p- mode as common final states of D0 and D0
bu(cd) & bc(ud) interference ( & B0 -B0 Mixing )
sin(2f1+f3) measurement via B0D(*)+p-
Dalitz analysis of B-  DK- (D  KS p- p+) decays to get f3 directly. (A.Giri, et. Al hep-ph/ ) Independently by Belle (unpublished) First Belle measurement hep-ex/
January 13, 2004
φ3 with BD0K Dalitz analysis

6. φ3 with BD0K Dalitz analysis
B+ D0K+ decay * *
If both D0 and D0 decay into the same final states
B+ D0K+ and B+ D0K+ amplitudes interfere.
Mixed state is produced:
Total phase
January 13, 2004
φ3 with BD0K Dalitz analysis

7. φ3 with BD0K Dalitz analysis
B+ D0K+ decay
in the case of no interference between and
Color suppression factor a2/a1=0.35 is estimated from the ratio of
B0 D0K0 and B+ D0K+ branching fractions (measured by Belle)
Use 3 body D0 decay, analyze Dalitz plot (fit relative amplitude a and phase θ)
for B+
can obtain both φ3 and δ separately
for B-
January 13, 2004
φ3 with BD0K Dalitz analysis

8. φ3 with BD0K Dalitz analysis
D0Ksπ+π- decay model
Use D0 3-body final state : B+D0(D0)K+KSp+p-K+
3-body decay is parameterized by 2-variables:m+2(Ksp+) & m-2(Ksp-)
Determine each D0 decay amplitudes by fitting relative amplitudes and relative phases.
January 13, 2004
φ3 with BD0K Dalitz analysis

9. Effect of D0-D0 interference
January 13, 2004
φ3 with BD0K Dalitz analysis

10. Statistical accuracy (MC study)
January 13, 2004
φ3 with BD0K Dalitz analysis

11. φ3 with BD0K Dalitz analysis
B+ D0K+ signal with 142 fb-1
|ΔE|<22 MeV
5.272<Mbc<5.288 GeV
|MD-1.86 GeV|<11 MeV
|cosΘthr|<0.8
Fisher discriminant F>-0.7
PID(K/π)>0.7
138 events
107±12 signal
32±3 background
Signal selection cuts:
January 13, 2004
φ3 with BD0K Dalitz analysis

12. B+ D0K+, D0Ksπ+π- Dalitz plot
K*(892) bands
70 events
68 events
D0 from B+ D0K+
D0 from B- D0K-
(π+ and π - interchanged)
January 13, 2004
φ3 with BD0K Dalitz analysis

13. φ3 with BD0K Dalitz analysis
Backgrounds
combinatorics (14%)
Fraction (together with D0): from ΔE distribution
Dalitz plot: from continuum data (off-Υ(4S) or on-resonance)
D0 from (3%)
Fraction (relative to combinatorial): from MD distribution
Dalitz plot: equal mixture of D0 and D0
B decays (2% neutral, 4% charged)
Fraction and Dalitz plot: from generic MC
“Wrong” particles in D0 decay (0.5%)
Fraction and Dalitz plot: from BD0K MC
BD0π with K/π misidentification (0.5%)
Fraction: from signal ΔE distribution
Dalitz plot: D0
Flavour tagging K from combinatorics (<0.4% at 95 C.L. from MC)
January 13, 2004
φ3 with BD0K Dalitz analysis

14. φ3 with BD0K Dalitz analysis
Extracting f3
Fit D0 Dalitz plots from B+D0K+ and B-D0K- processes simultaneously with three (a, f3 and d) free parameters. f3 f3 d d
January 13, 2004
φ3 with BD0K Dalitz analysis

15. Model uncertainty (MC study)
January 13, 2004
φ3 with BD0K Dalitz analysis

16. Source of model uncertainty
January 13, 2004
φ3 with BD0K Dalitz analysis

17. Model-independent approach
Preliminary
January 13, 2004
φ3 with BD0K Dalitz analysis

18. CP-tagged events at Charm Factories
CP properties of the D states produced in the Y(3700) are anticorrelated. If one D decaying as CP=+1 other state is “CP-tagged” as CP=-1
CP=+1
32,000 CP-tagged K+p- decays are expected for one year run at CLEO-c (G.Burdman, I.Shipsey hep-ph/ )
Based on this number we can estimate:
8,000 KSp+p-
6,000 p+ p- p0
1,500 KSK+K-
CP=-1
January 13, 2004
φ3 with BD0K Dalitz analysis

19. Comparison with indirect measurements
Our result
(68% CL)
January 13, 2004
φ3 with BD0K Dalitz analysis

20. φ3 with BD0K Dalitz analysis
Conclusion ~
Data from Charm Factory are necessary!
January 13, 2004
φ3 with BD0K Dalitz analysis

21. CLEO D0Ksπ+π- Dalitz plot analysis
January 13, 2004
φ3 with BD0K Dalitz analysis

22. CLEO D0Ksπ+π- data and fit
January 13, 2004
φ3 with BD0K Dalitz analysis

23. Event selection D*+ D0 π+,D0Ksπ+π-
January 13, 2004
φ3 with BD0K Dalitz analysis

24. Belle D0Ksπ+π- data and fit
January 13, 2004
φ3 with BD0K Dalitz analysis

25. Close look to D0Ksπ+π- plot projections
January 13, 2004
φ3 with BD0K Dalitz analysis

26. CLEO/Belle fit results
Preliminary
January 13, 2004
φ3 with BD0K Dalitz analysis

27. B+ D0K+Dalitz plot fit results (fixed a)
For fixed a=0.125:
January 13, 2004
φ3 with BD0K Dalitz analysis

28. B+ D0K+ Dalitz plot and projections
Fit result
Zero relative
amplitude
68 events
January 13, 2004
φ3 with BD0K Dalitz analysis

29. B- D0K- Dalitz plot and projections
Fit result
Zero relative
amplitude
70 events
January 13, 2004
φ3 with BD0K Dalitz analysis

30. φ3 with BD0K Dalitz analysis
B+ D0π+ signal with 142 fb-1
|ΔE|<22 MeV
5.272<Mbc<5.288 GeV
|MD-1.86 GeV|<11 MeV
|cosΘthr|<0.8
Fisher discriminant F>-0.7
PID(π/K)>0.5
1752 events
1655±52 signal
108±5 background
Signal selection cuts:
Used as a test sample for Dalitz plot fit
January 13, 2004
φ3 with BD0K Dalitz analysis

31. B+ D0π+, D0Ksπ+π- Dalitz plot
1752 events
January 13, 2004
φ3 with BD0K Dalitz analysis

32. φ3 with BD0K Dalitz analysis
Test sample fits
Fit complex relative amplitude
Expect a~ 0
B+ D0π+ (1750 events)
B+ D*0π+ (350 events)
a=0.065±0.020 (~1-2% probability for a=0), however no CP asymmetry
Need further investigation. Stat. fluctuation can not be excluded
January 13, 2004
φ3 with BD0K Dalitz analysis

33. Constraints on complex D0-D0 amplitude
January 13, 2004
φ3 with BD0K Dalitz analysis

34. B+ D0K+ Dalitz plot fit results
CL vs. (δ, φ3)
CL vs. (a, φ3)
-2 log L vs. φ3
For a, φ3 and δ as free parameters:
Two solutions:
(φ3, δ) and (φ3+π, δ+π)
January 13, 2004
φ3 with BD0K Dalitz analysis

35. φ3 with BD0K Dalitz analysis
Toy MC study
January 13, 2004
φ3 with BD0K Dalitz analysis

36. φ3 with BD0K Dalitz analysis
Strong phase value
January 13, 2004
φ3 with BD0K Dalitz analysis

37. φ3 with BD0K Dalitz analysis
Strong phase value
January 13, 2004
φ3 with BD0K Dalitz analysis