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Hadronic B Decays at BELLE and BABAR

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 + K 0 and B 0 →K 0 K 0 A CP of K +  - , K +  0 and  +  0 B + → ρ + K 0 B 0 → ρ 0 ρ 0 B 0 →  K*

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Hadronic B Decays at BELLE and BABAR

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  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

  2. Puzzle of K Buras, Fleischer et al, APO B36(2005)2015-2050 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

  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, 014003(2001) • There is no CP asymmetry in the B0→K0K0mode and small BF forB0 → K+ K- is expected if no strong FSI effect

  4. 449M BB 227M BB K+ - and + - B→+- hep-ex/0609015 B→K+- Sig(red) Con(dash) rareB(hatched) + -→K+- (dotted) PRD 75, 012008 (2007) sPlots Consider the final state radiation effects in these modes

  5. 449M BB 347M BB BF of K+π0,π+π0 and K0π0 hep-ex/0609015 K00 0 K0 0 K0 K00 hep-ex/0607106 hep-ex/0607096 • Simultaneous fit for π+π0 and K+π0 at Belle and BaBar • Use MES and Mmiss to extract yield for K0π0 at BaBar

  6. 449M BB 347M BB B→KK: Observation of b → d penguin K+K- K0π+ 5.3σ K0K+ 5.3σ 7.3σ K0K0 6.0σ PRL 97, 171805(2006) hep-ex/0608049(submit to PRL)

  7. Summary of B →hh

  8. Belle BaBar 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 SM Old WA Data Buras, Fleischer et al, APO B36(2005)2015-2050

  9. Direct CP Asymmetries(Belle) K+π-: -0.093±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/0608049(submit to PRL)

  10. 347M BB 383M BB Direct CP Asymmetries(BaBar) K+π-: -0.108±0.024±0.007(4.3σ) (2542±67) K+π0: 0.016±0.041±0.010 π+π0: -0.019±0.088±0.014 Acp(K+π-) - Acp(K+π0)  2.6σ hep-ex/0607106 • Observation of K+π- Direct CP asymmetry: • -0.107±0.018+0.007-0.004 (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% hep-ex/0703016(submit to PRL)

  11. 383M BB BF of B+→ρ+K0 andsearch for B+→ K*0K+ ρ+K0 • Pure penguin b→s PV decay • Branching Fraction : (8.0 +1.4-1.3 ±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/0702043 cosθρ Mπ+π0 • Dominated by the bdg penguin amplitude • bd analogue of B+ρ+K0 (both VP and penguin) ρ+K0

  12. 383M BB Evidence for B0→ρ0ρ0 • 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/0612020

  13. B0  K*0 384 M BB Full amplitude analysis: PRL 98: 051801, 2007 H2 H1 K*(892) K*(1430)

  14. 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

  15. 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 modesand 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

  16. Backup

  17. 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

  18. g p+ B0 p- PHOTOS E. Barberio, Z. Was Comput. Phys. Commun. 79,291 (1994) • 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 G.Nanava and Z.Was hep-ph/0607019

  19. Calibration of signal PDF Signal PDF MC Signal MC sample Data The PDF of data and MC are the same ? Control sample Like B-→D0-

  20. PID selection D*+→D0+, D0 →K-+ • 0 reconstruction efficiency D0→K-+ and D0→K-+0 • Track reconstruction efficiency D*+→D0+,D0→+-KS • KS reconstruction efficiency D+→K-++, D+→KS+ Correction of efficiency

  21. 2D Ext. Un-binned ML Fit

  22. Systematics of Br(Bhh) Systematics of FSR is about 1.0%

  23. Systematics of Acp • detector bias of Kπ0,ππ0from qq bkg in (ΔE, mbc) • detector bias of Kπfrom D*+　D0(Kπ)π+

  24. 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

  25. hep-ex/0610065 BF. of B0→00 277M BB 535M BB

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