1. Hadronic B Decays at BELLE and BABAR
Sheng-Wen Lin
National Taiwan University
B →K,  and KK
Ratios of Branching Fractions
Observation of B+ →K+K0 and B0 →K0K0
ACP of K+-, K+0 and +0
B+ →ρ+K0
B0→ρ0ρ0
B0→ K*
B0→a0-π+ and a0-K+
Conclusion
2007/3/18

2. Puzzle of K Within the SM: Rc-Rn≈0, Acp(K+π-) - Acp(K+π0)≈0
Buras, Fleischer et al, APO B36(2005)
Within the SM:
Rc-Rn≈0, Acp(K+π-) - Acp(K+π0)≈0
New Physics :
B0→π0K0 and B+→π0K+ may have color-allowed EW penguins form
Rc and Rn have sizeable effects by EW penguin
Described theoretically by q and 
q : strength of the EW penguin with respect to the tree contribution
: CP-violation phase
2007/3/18

3. Theory of KK
B+ →K0K+ and B0→K0K0 are dominated by b →d penguin
B0 → K+ K- is from annihilation diagram
J.-M. Gerard and W.-S. Hou, PLB 253, 478 (1991)
BF of B+ →K0K+ and B0→K0K0 are of order 10-6
Sizable asymmetry of O(45%) of B0→K0K0
C.-H. Chen and H.-n. Li, PRD 63, (2001)
There is no CP asymmetry in the B0→K0K0 mode and small BF for B0 → K+ K- is expected
if no strong FSI effect
2007/3/18

4. K+ - and + - 449M BB 227M BB B→+- B→K+-
hep-ex/
B→+-
B→K+-
Sig(red)
Con(dash)
rareB(hatched)
+ -→K+- (dotted)
227M BB
PRD 75, (2007)
sPlots
Consider the final state radiation effects in these modes
2007/3/18

5. BF of K+π0,π+π0 and K0π0 449M BB K00 0 K0 0 347M BB K0 K00
hep-ex/
K00
0
K0
0
347M BB
K0
hep-ex/
K00
hep-ex/
Simultaneous fit for π+π0 and K+π0 at Belle and BaBar
Use MES and Mmiss to extract yield for K0π0 at BaBar
2007/3/18

6. B→KK: Observation of b → d penguin
449M BB
K+K-
347M BB
K0π+
5.3σ
K0K+
5.3σ
K0K0
7.3σ
6.0σ
hep-ex/ (submit to PRL)
PRL 97, (2006)
2007/3/18

7. Summary of B →hh
2007/3/18

8. 2007/3/18

9. New Electroweak Penguins in the Ratios Rn and Rc
q: measures the importance of the EW penguins with respect to the
tree-diagram-like topologies
: CP-violating weak phase
BaBar
Belle SM
Old WA Data
Buras, Fleischer et al, APO B36(2005)
2007/3/18

10. Direct CP Asymmetries(Belle)
K+π-: ±0.018±0.008
(4.7σ)
K+π0: 0.07±0.03±0.01
(2.3σ)
π+π0: 0.07±0.06±0.01
Acp(K+π-) - Acp(K+π0)
4.4σ
Preliminary
The other decay modes:
hep-ex/ (submit to PRL)
2007/3/18

11. Direct CP Asymmetries(BaBar)
K+π-: ±0.024±0.007(4.3σ) (2542±67)
K+π0: 0.016±0.041±0.010
π+π0: ±0.088±0.014
Acp(K+π-) - Acp(K+π0)  2.6σ
347M BB
hep-ex/
Observation of K+π- Direct CP asymmetry:
-0.107± (5.5σ) (4372±82)
Using dE/dx as a discriminating variable in the M.L. fit
|cosθSpher|<0.9→ |cosθSpher|<0.8
Total increase in rec. eff. is 52%
383M BB
hep-ex/ (submit to PRL)
2007/3/18

12. BF of B+→ρ+K0 and search for B+→ K*0K+
383M BB
ρ+K0
Pure penguin b→s PV decay
Branching Fraction :
( ±0.5)x10-6 (7.9σ)
CP asymmetry:
(-12.2±16.6±2.0) %
Observation of this mode
BF and ACP are consistent with SM
hep-ex/
Mπ+π0
cosθρ
Dominated by the bdg penguin amplitude
bd analogue of B+ρ+K0 (both VP and penguin)
ρ+K0
2007/3/18

13. Evidence for B0→ρ0ρ0 383M BB tree contribution is color-suppressed
→decay rate is sensitive to the penguin amplitude
Complete the isospin triangle
Branching Fraction:
B0→ρ0ρ0:1.07±0.33±0.19 x10-6 (3.5σ)
Upper limit:
B0→ρ0f0(980),f0→π+π-: < 0.53 x 10-6
B0→f0(980)f0(980),f0→π+π-: < 0.16 x 10 -6
longitudinal polarization fraction :
0.87 ±0.13± 0.04
hep-ex/
2007/3/18

14. B0  K*0 Full amplitude analysis: 384 M BB H2 H1 K*(892) K*(1430)
PRL 98: , 2007 H2 H1
K*(892)
K*(1430)
2007/3/18

15. Search for B0→a0-π+and a0-K+
Preliminary
a0-π+
a0-K+
a0(1450)-π+
a0(1450)-K+
Evidence taht a0(980) meson is a four-quark state
2007/3/18

16. Conclusion Kπpuzzle Two ratios: Rn, Rc
 Belle : consistent with SM prediction
BaBar : also move towards SM prediction
Significant difference between Acp(K+π-) and Acp(K+π0)
Large colour-suppressed trees
Observation of b →d modes and B+→ρ+K0
Only from BaBar
Evidence of B0→ρ0ρ0 at BaBar
fL~0.5 in BK*, implies |A0|  |A+1| >> |A-1|
a0(980) meson like a four-quark state
2007/3/18

17. Backup
2007/3/18

18. B signal reconstruction
The signal yield are usually extracted by Mbc and ΔE
Beam constrained mass :
Precise beam energy known from accelerator
Lower error on momentum resolution
Energy difference :
Asymmetry shape and shift due to energy loss
Ebeam : run dependent beam energy
EB* and PB* are the reconstructed energy and momentum of the B candidates
in CM frame
2007/3/18

19. PHOTOS g Final state radiation (FSR) effects:
E. Barberio, Z. Was
Comput. Phys. Commun. 79,291 (1994) p- p+ g B0
Final state radiation (FSR) effects:
PHOTOS included in our MC
for all B→hh modes.
Systematic uncertainty of PHOTOS
in B→hh now calculated ~ 1/million
(negligible for non-SUPERB statistics):
PHOTOS v 2.13
Interference on,
double photon on,
Ecut~26MeV
Impact on eff w/o PHOTOS
p+p-
K+p-
h+p0
9.4%
5.8%
3.6%
G.Nanava and Z.Was hep-ph/
2007/3/18

20. Calibration of signal PDFMC
Signal MC sample
Data
The PDF of data and MC are the same ?
Control sample
Like B- →D0-
2007/3/18

21. Correction of efficiency
PID selection
0 reconstruction efficiency
Track reconstruction efficiency
KS reconstruction efficiency
D*+ →D0+, D0 →K-+
D0→K-+ and D0→K-+0
D*+→D0+,D0→+-KS
D+→K-++, D+→KS+
2007/3/18

22. 2D Ext. Un-binned ML Fit
2007/3/18

23. Systematics of Br(Bhh)
Systematics of FSR is about 1.0%
2007/3/18

24. Systematics of Acp detector bias of Kπ0,ππ0 from qq bkg in (ΔE, mbc)
detector bias of Kπ　from D*+　　D0(Kπ)π+
2007/3/18

25. B0 → 00
Time information
On time
9000<t<11000
Too late
Too early
Difficult to model the distribution for off-time QED background with MC
Re-process the raw-data for timing information
Off-time events
~5.28GeV/c2
Bhabha events
2007/3/18

26. BF. of B0 →00
hep-ex/
277M BB
535M BB
2007/3/18