1. 2004/8/16-22ICHEP041-Outline- Introduction B +  ΛΛK + B +  pΛγ Threshold enhancement Charmed baryonic modes Conclusion-Outline- Introduction B +  ΛΛK + B +  pΛγ Threshold enhancement Charmed baryonic modes Conclusion Baryonic B decays at BELLE Min-Zu Wang National Taiwan University (Belle Collaboration) mwang@phys.ntu.edu.tw

2. M.-Z. Wang 2004/8/16-22 ICHEP04 2 Introduction Baryonic decays: a unique feature of B meson Well established after few years of B- factory running BF(2-body) < BF(3-body) < BF(4-body) Threshold enhancement in the baryon- antibaryon system Searching ground for exotic states Recent status report: H.Y. Cheng, Recent status report: H.Y. Cheng, hep-ph/0311035

3. M.-Z. Wang 2004/8/16-22 ICHEP04 3 g b s ss B +  ΛΛK + First observation of b  s s s decay Signal Yield in 2D fit: 19.9 Efficiency: 4.0%-6.9% Statistical Significance: 7.4σ BF: 2.91 ± 0.38 x 10 -6 +6.5 - 5.1 +0.90 - 0.70 submitted to PRL submitted to PRL 1.First Charmless B decay with two Λ! 2.Threshold enhancement again. 3.Compliment to B  φK (*) (b  sss penguin) 1.First Charmless B decay with two Λ! 2.Threshold enhancement again. 3.Compliment to B  φK (*) (b  sss penguin) 140fb -1 threshold peaking

4. M.-Z. Wang 2004/8/16-22 ICHEP04 4 Search for B +  ΛΛπ + No significant signal found for these two modes. 90% confidence-level upper-limit: B (B +  ΛΛπ + )<2.8x10 -6 Submitted to PRL 140fb -1 1.Compare with B  pp π 2.b  uud transition with ss popping 1.Compare with B  pp π 2.b  uud transition with ss popping Result Number of Background: 37.5±1.0 Number of Observed events： 41 Number of Signal UL: < 21.7

5. M.-Z. Wang 2004/8/16-22 ICHEP04 5 Theoretical prediction: *Pole Model *Pole Model: Phys.Lett. B533 (2002) BF(B  pΛγ ) ~ 1.2x10 -6 BF(B  pΣ 0 γ) ~ 2.9x10 -9 *QCD counting rules *QCD counting rules: (hep-ph/0405283) BF(B  pΛγ ) ~ (1.2-2.4)x10 -7 BF(B  pΣ 0 γ) ~ (2.8-6.5)x10 -7 B +  pΛγ First observation! Simultaneous fit on B  pΛγ and B  pΣ 0 γ Signal Yield for B  pΛγ with M p Λ <2.4GeV/c 2 : 34.1 Statistical Significance: 8.6σ BF(B  pΛγ ): 2.16 ± 0.20x10 -6 BF( B  pΣ 0 γ ):<3.3 x 10 -6 140fb -1 +7.1 - 6.6 +0.58 - 0.53 b  sγ MC pΛγSignal Preliminary

6. M.-Z. Wang 2004/8/16-22 ICHEP04 6 Photon energy and Angular distribution Fit results in bins of cosθ X with M pΛ <4.0GeV/c 2 (Assuming X  pΛ, calculated in X rest frame.) Λ γ p θxθx b  sγ MC Signal Yield qq background Signal Yield

7. M.-Z. Wang 2004/8/16-22 ICHEP04 7 Improved B +  ppK + measurement threshold peaking Signal Yield in 2D fit: 216.5 Efficiency: 28.3%-35.2% BF: 4.59 ± 0.50 x 10 -6 ( 4.89 x 10 -6 PRL92, 131801, 2004) +17.3 - 16.6 140fb -1 +0.38 - 0.34 Preliminary

8. M.-Z. Wang 2004/8/16-22 ICHEP04 8 Angular distribution: ppK + b  s dominant process Fragmentation picture u s uud duu u s K+K+ pp p p K+K+ ӨpӨp X Proton against K - (p against K + ) : flavor dependence! ppK signal at pp rest frame

9. M.-Z. Wang 2004/8/16-22 ICHEP04 9 Glueball Search Possible Hints and Search for Glueball Production in Charmless Rare B Decays Chun-Khiang Chua, Wei-Shu Hou and Shang-Yuu Tsai(PLB544,2002) Scanning through the mass region from 2.2 to 2.4 GeV region No significant signal is found. We set a 90% confidence-level upper limit: BF(B +  glueball K + ) x BF( glueball  pp) < 4.1x10 -7 Preliminary

10. M.-Z. Wang 2004/8/16-22 ICHEP04 10 Improved B 0  ppKs measurement threshold peaking Signal Yield in 2D fit: 28.6 Efficiency: 15.4%-21.0% BF: 1.04 ± 0.12 x 10 -6 ( 0.78 x 10 -6 PRL92, 131801, 2004) +6.5 - 5.8 140fb -1 +0.26 - 0.19 Preliminary

11. M.-Z. Wang 2004/8/16-22 ICHEP04 11 Angular distribution: ppKs p p Ks ӨpӨp X Flavor information is not applied due to small statistics ppKs signal at pp rest frame ~1+cos p 2

12. M.-Z. Wang 2004/8/16-22 ICHEP04 12 Pentaquark search in ppKs Θ + (1540) : uudds Θ +  K + n Θ +  K 0 p B 0  Θ + p B 0  ppK 0, B  ppKs Search for B signal with a 20 MeV pKs mass window cut at 1540MeV dd u us Θ+Θ+ K+K+ n su dd u uu d p ds K0K0 Θ+Θ+ uu d sd

13. M.-Z. Wang 2004/8/16-22 ICHEP04 13 Pentaquark search in ppKs Fixed background shape from sideband data Count the events in signal region and compare with background estimation BF product upper limit < 2.3 x10 -7 at 90% C.L. Preliminary

14. M.-Z. Wang 2004/8/16-22 ICHEP04 14 Improved B 0  pΛ π - measurement threshold peaking Signal Yield in 2D fit: 48.4 Efficiency: 10.4%-12.6% BF: 3.27 ± 0.46 x 10 -6 (2.73 x 10-6 PRL90, 201802, 2003) 140fb -1 +8.2 - 7.4 +0.61 - 0.43 Preliminary

15. M.-Z. Wang 2004/8/16-22 ICHEP04 15 Angular distribution: pΛ π - π-π- Λ p ӨpӨp X at pΛ rest frame Λ p π-π- ӨpӨp X at p π - rest frame Fragmentation picture

16. M.-Z. Wang 2004/8/16-22 ICHEP04 16 Preliminary B -   C + p  - 264±20 signals  C (2455) 0  C (2520) 0 sideband 32.6 12.8 + 6.6 - 5.9 - 5.9 + 5.7 - 5.0 - 5.0 Belle: new results 140 fb -1 B -   c + p -  20.1±1.5 ±2.0±5.2 B -   c 0 2455 p  3.67 ±0.36 ±0.95 B -   c 0 2520 p  1.26 ±0.12 ±0.33 BF x 10 -5 +0.74 - 0.66 +0.56 - 0.49 ~ 25% of total BF b c ud Observation of new 2-body decay

17. M.-Z. Wang 2004/8/16-22 ICHEP04 17 Preliminary (  c + p) mass  C + p) M(  c +  -)>2.6 & M(p  -) >1.6GeV/c 2 to remove  c(2455/2520) &  (1232) B signals by  E fit for each mass bin B -   C + p  - M(  c + p) structure BF = ( 3.87 ±0.43 ±1.01 ) x 10 - 5  BW = 0.09±0.04 ± 0.04 M = 3.34 ±0.02 6.2  significance  C 0  C +  - ) Low mass structure Phase space function +0.77 - 0.72 +0.02 -0.03

18. M.-Z. Wang 2004/8/16-22 ICHEP04 18 MC helicity  2 /nd Solid line : 0 0.97 Dashed line : 1 1.58 B -   C + p  - ( by  E fit for each mass bin ) Helicity distribution data: dots MC : histograms Preliminary M(  c + p) <3.6GeV/c 2 c+c+  (  c + p) direc. in B - at rest Helicity angle p

19. M.-Z. Wang 2004/8/16-22 ICHEP04 19 Preliminary B 0   C + p  -  -  c ++ (2455)  c 0 (2455)  c ++ (2520)  c 0 (2520) M(  c +  ) Intermediate 3-body decays Belle 140 fb -1 B 0   c + p     10.3±0.9 ±1.2 ±2.7 (*1) B 0   c2455 ++ p    1.15±0.22 ±0.14 ±0.30 B 0   c2455 0 p    0.97±0.21 ±0.12 ±0.25 B 0   c2520 ++ p    1.04±0.234±0.12 ±0.27 B 0   c2520 0 p    0.33±0.19 ±0.054±0.09 41.0±8.035.2±7.8 58±1419±11 M(  c +   )+c.c. M(  c +   )+c.c. (*1) total BF

20. M.-Z. Wang 2004/8/16-22 ICHEP04 20 B 0  (  c + p)    - M(  c + p) structure in 3, 4 body decays  C ++/0 (2455/2520) excluded B -  (  c + p)  - B Signals by  E fit consistent with 4-body MC phase space, fine structures ? MC 4-body phase space Preliminary

21. M.-Z. Wang 2004/8/16-22 ICHEP04 21 Conclusion First b → sss hyperonic decay found First b → s γ baryonic decay found The threshold enhancement in the baryon- antibaryon pair system supports a fragmentation picture Detailed structures studied in charmed baryonic decays No hints for pentaquarks and glueballs yet Keep searching for all kinds of baryonic decay channels, possible pentaquarks, glueballs and especially direct CP violation with increasing statistics

22. M.-Z. Wang 2004/8/16-22 ICHEP04 22 B = 1.5T ∆r IP ∆φ∆φ π p Fly length Z dist Λ Λ reconstruction Y Z X Good Λselection is applied in those analyses.

23. M.-Z. Wang 2004/8/16-22 ICHEP04 23 Thretical Prediction The radiative baryonic B decays (B  BB ’ γ ) are of interest because of the rich spin structures. (CP / T violation). They could arise from b  sγ transition. Predicted Branching Fraction: Pole Model: (hep-ph/0311035) Phys.Lett. B533 (2002) Br(B  PΛγ ) ~ 1.2x10 -6 Br(B  PΣ 0 γ) ~ 2.9x10 -9 QCD counting rules: (hep-ph/0405283) Br(B  PΛγ ) ~ (1.2-2.4)x10 -7 Br(B  PΣ 0 γ) ~ (2.8-6.5)x10 -7 Upper-bound from CLEO: Br(B  PΛγ )+0.3Br(B  pΣ 0 γ)| Eγ>2.0GeV < 3.3x10 -6 0.4Br(B  PΛγ )+ Br(B  pΣ 0 γ)| Eγ>2.0GeV < 6.4x10 -6

24. M.-Z. Wang 2004/8/16-22 ICHEP04 24 The KEKB-factory Electron 8 GeV Positron 3.5 GeV Υ(4S) (10.58GeV/c 2 )  = 0.425 Υ(4S) (10.58GeV/c 2 )  = 0.425 e + + e -  Υ(4S)  B + + B - e + + e -  Υ(4S)  B 0 + B 0 Interaction Point 3Km Tsukuba

25. M.-Z. Wang 2004/8/16-22 ICHEP04 25 A erogel C herenkov C nt. n=1.015~1.030 KLM  / K L detection 14/15 lyr. RPC+Fe TOF counter ECL CsI(Tl) SC solenoid 1.5T Silicon Vertex Detector C entral D rift C hamber small cell +He/C 2 H 5 8 GeV e - 3.5 GeV e + Belle Detector E xtreme F orward C alorimeter

26. M.-Z. Wang 2004/8/16-22 ICHEP04 26 Particle Selection PID (ACC+CDC+TOF) We use the PID (ACC+CDC+TOF) system to identify the charged particles. Proton: Kaon: Pion: Λ: reconstructed from Λ  pπ -pKπ(p) (K) ~9%~10% (π)(π)(π)(π) ~4%~8% Fake rate From TO

27. M.-Z. Wang 2004/8/16-22 ICHEP04 27 B Signal Reconstruction In Υ(4S) rest frame: e-e- e+e+ Υ(4S) B B e-e- e+e+ ∆E∆E M bc 2D scatter plot 1D projection plot

28. M.-Z. Wang 2004/8/16-22 ICHEP04 28 B decay continuum events Υ(4S) The main background for B 0  pΛπ - and B +  ΛΛ π + is continuum qq events. (q=u,d,s,c). The Topology of continuum events and B decays are different. We choose |cosθ Thrust | S ⊥ R 2 so R 4 so R 2 oo R 3 oo R 4 oo as the fisher input and combine it with cosθ B to calculate the likelihood ratio. We define the Super-fox wolfram moment (F) like: We use Fisher ’ s discriminant to optimize the coefficients. Background suppression

29. M.-Z. Wang 2004/8/16-22 ICHEP04 29udsoff Data sideband charm Background Suppression SFW Moment (F) cosθ B distribution uds off Data sideband charm Signal MC udscharm off Data sideband Likelihood Ratio (LR) Optimized by study

30. M.-Z. Wang 2004/8/16-22 ICHEP04 30 Signal Extraction PDFs: Background modeling: a line (curve) to represent the ∆E and the following parametrization first suggested by ARGUS group to represent the M bc. Signal modeling: a double Gaussian for ∆E and a Gaussian for M bc. 1D-binned fit: maximum Likelihood fit Branching fraction are calculated by ∆E fit M bc fit for cross-check. 2D-unbinned fit (∆E-M bc ): Extended maximum likelihood fit. ∆E M bc

31. M.-Z. Wang 2004/8/16-22 ICHEP04 31 Angular distribution: ppK + Background yield of ppK + Consistent with qq background process No fragmentation signature in J/ψK + J/ψK + (J/ψ  pp)