1. Search for b → u transitions in B+ → {Kpp0}DK+
Denis Derkach and Achille Stocchi
BaBar-France meeting
Orsay,

2. Outlook ADS study of B+→D0(D0)K+ , D0 →K-p+p0 selection;
likelihood fit validation;
rB extraction.

3. CKM angle g
Wolfenstein parameterization
l~0.22 A~0.8
r~0.16 h~0.34

4. g measurement
g = 88° ± 16° 95% Prob.) g = -92° ± 16° 95% Prob.)
ADS:
D. Atwood, I. Dunietz, A. Soni Phys.Rev.Lett. 78 (1997) 3257
GLW:
M. Gronau, D. London Phys.Lett.B253: ,1991.
M. Gronau, D. Wyler Phys.Lett.B265: ,1991
Dalitz:
A. Giri, Yu. Grossman, A. Soffer and J. Zupan,{Phys. Rev.} D68, (2003)

5. Current Situation (B+→DK+)

6. { { { { } B+→DK+ system } } D g+dB “Vcb” channel “Vub” channel Vus u
Vcs s D B+ K+ u u u
Relative phase
g+dB u c { b } { c
Vub
Vcs u b
Vcb B+ u u B+
Vus } s K+ u K+ s u u

7. Idea of the ADS method Opposite sign events (os) Vcb B+ →D0K+ D0 →f B+
DCS
Vcb
B+ →D0K+
D0 →f B+
B+ →[K- p+p0]D0 K+
D0 →f
B+→D0K+
Vub CA
for f=K+p-p0 CA
Vcb
B+ →D0K+
D0 →f B+
B+ →[K+ p-p0]D0 K+
D0 →f
B+ →D0K+
Vub
DCS
Same sign
events (ss)

8. D→ multibody state
CLEO-C, arXiv: v1

9. Observables Good sensitivity to rB Allows to extract more
Hard to measure AADS
Allows to extract more
information but DR+>DRADS

10. Selection
Last analysis was performed with R14 on runs fb-1 (Phys.Rev.D76:111101,2007)
This analysis: R24 BchToD0KAll skim is used. Runs 1-6 with 428 fb-1.
|DEB|<23 MeV
0.12 GeV/c2<Mp0<0.146 GeV/c2
|dM - dMPDG|< GeV/c2
|cos(QBcm)|<0.8
K very tight
Selection criteria optimization
was performed for os simulated
events
The only source of peaking background found is This peaking background is essential only in same sign channel.

11. Continuum background rejection
After extensive studies of NN and Fisher we have decided to use Fisher
discriminant constructed of 6 variables to reject the continuum background.
The optimization was done using TMVA 4.0.3
Variables used:
L10
L12
|cos(qthrust)| cosine between B thrust axis and thrust axis of the rest of the event
|Dt| proper time interval between B decays
DOCA distance of closest approach between two tracks forming B meson
DistB-D distance between B and D vertices } os
polar moments ss

12. Efficiency Tables (os)
Selection criteria
signal
B+B-
B0B0 cc
uds
s (os)
preselection
92,1
13690
4763
304385
256273
0,12
|DEB|<23 MeV
70,0
3429
1198
75923
63291
0,18
0.12 GeV/c2<Mp0<0.146 GeV/c2
65,8
2331
811
55274
45442
0,20
|dM - dMPDG|< GeV/c2
57,8
1416
505
36537
27557
0,22
|cos(QBcm)|<0.8
54,4
1177
413
29520
22178
0,23
K very tight
37,2
369 99
14712
6506
0,24
mES>5.27 GeV/c2
37,1 71 21
2016
1014
0,49
Fisher>0
31,5 58 20
445
166
0,59
ss signal reconstruction efficiency ~ 9.7%

13. Efficiency Tables (ss)
Selection criteria
signal
B+B-
B0B0 cc
uds Dp
s (ss)
preselection
6165
22949
8180
206176
195072
16349 9
|DEB|<23 MeV
4703
5394
2015
51711
48243
3579 14
0.12 GeV/c2<Mp0<0.146 GeV/c2
4412
3646
1380
36832
34716
2850 15
|dM - dMPDG|< GeV/c2
3883
2294
844
23621
21060
2266 17
|cos(QBcm)|<0.8
3667
1933
698
19076
16884
2103
K very tight
2492
340
121
4322
3146
176 24
mES>5.27 GeV/c2
2489
135 44
584
460
160 40
Fisher>0
2127
111 38
124 82
130 42
ss signal reconstruction efficiency ~ 9.5%

14. Likelihood Fit Structure
Extended MLL fit to (mES, Fisher) for the ss and os components
Species:
os signal;
ss signal;
os BB combinatorial background;
ss BB combinatorial background;
os continuum background;
ss continuum background;
ss peaking background.
Same PDF parameterization
Npeak is fixed in the fit from MC
Nsig,tot=Nos,sig+Nss,sig
Fitted:
RADS, Nsig,tot
NBB,os, NBB,ss
Ncont,os, N cont, ss
(Shape cont)os, (Shape cont)ss
is fitted directly
to avoid systematics.

15. Parameterization from MC (os)
signal
Double Bifurcated Gaussian
Double Bifurcated Gaussian
BB background
Crystal Ball
Double Gaussian
continuum background
ARGUS
Triple Gaussian

16. Parameterization from MC (os)
signal
Double Bifurcated Gaussian
Double Bifurcated Gaussian
BB background
Crystal Ball
Double Gaussian
continuum background
ARGUS
Triple Gaussian

17. Parameterization from MC (ss)
signal
Double Bifurcated Gaussian
Double Bifurcated Gaussian
Peaking background
BB background
Crystal Ball
Double Bifurcated Gaussian
continuum background
ARGUS
Double Gaussian

18. Parameterization from MC (ss)
signal
Double Bifurcated Gaussian
Double Bifurcated Gaussian
Peaking background
BB background
Crystal Ball
Double Bifurcated Gaussian
continuum background
ARGUS
Double Gaussian

19. Parameterizations from Data
We use the control sample
B+→D0p+, D0 →K+p-p0
to get the “signal” mES parameterization.
We use the 44 fb-1 of off-resonance data to get the “continuum” Fisher parameterization.

20. Control Sample Parameterization
Fitted from CS
Signal (sum of B+→D0K+ and B+→D0p+)
Double Bifurcated Gaussian
BB background
(excluding B+→D0K+)
Crystal Ball
Double Bifurcated Gaussian
continuum background
ARGUS
Double Gaussian

21. Control Sample Parameterization
B+→D0p+, D0 →K+p-p0 (only same sign events)
mES
Fisher
mES, Fisher>0.5
mES, zoomed to signal region
We got mES parameters from the fit

22. Control sample parameterization vs. MC
Blue curve : CS fitted parameters
Black points : MC events
Important to use the signal parameterizations directly from data (CS)

23. Continuum Fisher parameterization
Offresonance data
os events
ss events
MC vs data

24. Toy MC expectations (RADS=1.4*10-2 )
Errors are asymmetrical!
Pull mean =-0.02
Pull RMS = 1.004
Error expected 6.5*10-3 for generated value RADS=1.4*10-2
Example :
With such an error we could
get an rB as in the plot 

25. Toy MC expectations (RADS=0)
Pull mean =-0.05
Pull RMS = 1.05
Error expected 5.2*10-3 for
Generated value RADS=0
Errors are asymmetrical!

26. Fit validation on full MC sample (RADS=1.4*10-2 )
Same sign
mES
Fisher
Opposite sign
Fisher
mES

27. Fit validation on full MC sample (RADS=1.4*10-2 )
mES, Fisher>0.5, opposite sign
mES, Fisher>0.5, same sign

28. Fit validation on full MC sample (RADS=0.)
Same sign
mES
Fisher
Opposite sign
Fisher
mES

29. Fit validation on full MC sample (RADS=0.)
mES, Fisher>0.5, opposite sign
mES, Fisher>0.5, same sign

30. Results for MC cocktails
Generated
Cocktail
with signal 1
no signal 1
with signal 2
no signal 2
Nsignal, total
2529 or 2492
2531±61
2480±60
2489±61
2460±61
RADS
14*10-3 or 0
(29±7)*10-3
(9±6)*10-3
(6±7)*10-3
(-9±5)*10-3
NBB, SS
467
440±61
440±60
384±60
NBB, OS
460
320±66
330±70
520±67
522±66
Ncont, OS
21229
21326±157
21320±157
21179±157
21178±156
Ncont, SS
7468
7520±98
7520±90
7561±99
7565±100
The fit is performed with
signal mES parameterization from MC
Inside 1s
Inside 2s
Inside 3s

31. Systematics error Source PDF error Peaking background BR errors
1*10-3
Peaking background
BR errors
Crossfeed ss<->os ratio
6*10-4
Efficiency ratio
2*10-4
Combined error
2*10-3
Estimation is done randomly varying the parameters (or yield) fixed in the fit.
Estimation is done according to number of ss events passing os selection.
Estimation is done by reweighing the Dalitz distribution of CA and DCS decays (crucial information is obtained from the estimation on B0->D0K*0 analysis.
Statistical error > 5*10-3

32. R+/- vs. RADS
We plan to quote R+, R- and RADS as final results and quote rB from R+ / R-

33. Future plans Unblind the fit. Publish the results. More details in:
BAD 2173 physics note;