1. 1 Belle & BaBar “Competition” Y.Sakai, KEK ASEPS 24-March-2010

2. Introduction 2 PEP-II / BaBar & KEKB / Belle Asymmetric energy e + e - B-factory Goal: Quest for CP Violation in B-decays Prove Kobayashi-Maskawa theory Same Goal with Same approach at Same time Intense “Competition” Many common issues  “Collaboration” (G.Wormser)

3. Asymmetric B-factory 3 New idea to realize CPV measurement at Y(4S) ! 1987: P.Oddone e + e - collider in 1 ring : E + =E -  B ~at rest 1991: 7 proposals in the world ! Only PEP-II (SLAC) & KEKB survived ! e + e - collider in 2 rings : E + <E -  B boosted Decay-time measurable

4. PEP-II & KEKB projects 4 PEP-II KEKB Officially approved: Oct-1993 Jan-1994 Start Acc. operation: late-1998 Mar-1999 Start Data taking: May-1999 Jun-1999 Both maximally utilize existing accelerators PEP TRISTAN ~5 years construction time Competition

5. KEKB vs PEP-II accelerator 5 PEP-II BaBar ~3 km circumference Mt. Tsukuba KEKB Belle ~2.2 km circumference 8 GeV e - x 3.5 GeV e +  11mrad crossing 9 GeV e - x 3.1 GeV e + Head-on collision KEKB (Japan) PEP-II (USA)  =0.425  =0.56 SLAC

6. 6 Belle & BaBar collaborations IHEP, Vienna ITEP Kanagawa U. KEK Korea U. Krakow Inst. of Nucl. Phys. Kyoto U. Kyungpook Nat’l U. EPF Lausanne Jozef Stefan Inst. / U. of Ljubljana / U. of Maribor U. of Melbourne Aomori U. BINP Chiba U. Chonnam Nat’l U. U. of Cincinnati Ewha Womans U. Frankfurt U. Gyeongsang Nat’l U. U. of Hawaii Hiroshima Tech. IHEP, Beijing IHEP, Moscow Nagoya U. Nara Women’s U. National Central U. National Taiwan U. National United U. Nihon Dental College Niigata U. Osaka U. Osaka City U. Panjab U. Peking U. U. of Pittsburgh Princeton U. Riken Saga U. USTC Seoul National U. Shinshu U. Sungkyunkwan U. U. of Sydney Tata Institute Toho U. Tohoku U. Tohuku Gakuin U. U. of Tokyo Tokyo Inst. of Tech. Tokyo Metropolitan U. Tokyo U. of Agri. and Tech. Toyama Nat’l College U. of Tsukuba VPI Yonsei U. 15 countries, 61 institutes, ~400 collaborators

7. 7 Belle and BaBar Detectors Si Vertex detector Drift Chamber (small cell) CsI(Tl) EM calorimeter  /K L detector (RPC+Fe) SC solenoid (1.5T) TOF counter & Aerogel Cherenkov DIRC Huge high speed “Digital Camera” High precision Good PID

8. Luminosities 8 2000 6/9M 2001 31/32M 2002 78/88M 2003 summer 152/123M Peak Luminosity (x10 33 /cm 2 s) Integ. Luminosity (/fb) First 3 years Critical Dead heat ! 1 st observation of CPV: 2001 !

9. CP Violation : History 9 2000 summer First measurement of B-factories (ICHEP Osaka) Belle/BaBar Joint Press release B 0  J/  Ks _ CP Measure decay-time distribution Difference  CP Violation Size of CPV = sin2  1

10. CP Violation : History 10 2001 Winter First CPV Papers By B-factories Belle: PRL 86, 2509 BaBar: PRL 86, 2515

11. CP Violation : History 11 2001 Summer First Observation of CPV by B-factories (LP01 Rome) BaBar: PRL 87, 091801 Belle: PRL 87, 091802

12. First Observation: CPV in B 12 1137 events B 0 tag _ Asymmetry 31M BB 2001 Summer 0.59  0.14  0.05 sin2   = 0.99  0.14  0.06 _ 32M BB [PRL 87,091802(2001)] [PRL 87,091801(2001)] J/  K* 0 ( ) Asymmetry Events

13. sin2  1 : Obs.  Precise meas. 13 0.670  0.023 0.687  0.028  0.012 BaBar/Belle Quite good agreement Similar stories for other various measurements

14. Validation of KM Theory 14 All measurements are consistent CP Violation: Source is single complex phase of KM-matrix CP Violation: Source is single complex phase of KM-matrix 2008 Physics Nobel Prize Validation by BaBar & Belle

15. Conclusion 15 BaBar /PEP-II & Belle /KEKB  New generation of e + e - collider (asymmetric energy) 1 st Observation of CPV, confirmed KM theory  Explored New Era of B, , charm physics Intense Competition !Benefit each other ! Hints & Potentials for Physics beyond SM Competition ! LHC(ATLAS/CMS), LHCb SuperKEKB, SuperB

16. backup 16

17. B 0      : CPV 17 ( C =  A ) Deviation 1.9  Belle/BaBar latest Av. >5  DCPV confirmed

18. Discoveries of New Resonances 18  c ’ & e + e -  cccc D 0 * 0 & D 1 * 0 X(3872)  c * baryon triplet X(3940), Y(3940)  c2 ’ Y(4660) Y(4008) D sJ (2700)  cx (3090) Z(4430) D sJ (2317/2460) D sJ (2860) Y(4260) Y(4320) Integrated Luminosity Neutral Charged u c u c d c u c u u c c c c g Hybrid Cluster Tetraquark “Exiotic Hadrons” X(3915), Y(4350) Z(4050),Z(4250)Yb

19. Time-dep. CPV Measurement 19 Flavor-tag (B 0 or B 0 ?) J/  (  ’) KSKS ee ee zz t=0 f CP Vertexing Reconstruction Extract CPV fit B0B0 B0B0 B 0 -tag  t   z/c   eff ~30%   t ~140ps  =0.425 (KEKB)  0.56 (PEP-II) same analysis method applied for all modes

20. Now: Precise measurement 2020 B 0 tag _ _ 465M BB 535M BB B  J/  Ks B  J/  K L _ (cc)K (*)0 [PRD 79,072009(2009)] CP-even CP-odd 0.687  0.028  0.012 sin2   = 0.650  0.029  0.018 [PRL 98,031802(07)+PRD77 091103(08)] Av. 0.670  0.023: 3.4% error ! +  (2S)K S 14000 signals 12000 signals