 1 measurements with tree-level processes at Belle O. Tajima (KEK) Belle collaboration ICHEP06 July 28, 2006

2 Kobayashi-Maskawa Phase CP violation parameters (  1,  2,  3 ) = ( , ,  ) CP violation parameters (  1,  2,  3 ) = ( , ,  ) ~ 0.22 CP violation is due to a complex phase in quark mixing matrix CP violation is due to a complex phase in quark mixing matrix

3 _ d b _ c c s d _ w B0B0 J/  K0K0 sin2  1 measurement V* td __ t d t b b d _ w w B0B0 B0B0 _ B0B0 B0B0 qpqp f CP = A CP  (  t ; B 0  J/  K 0 )   (  t ; B 0  J/  K 0 )  (  t ; B 0  J/  K 0 )   (  t ; B 0  J/  K 0 ) _ _ = -  cp sin2  1 sin(  m  t) + A cos (  m  t) Mixing induced CPV Direct CPV (A =  C)  CP : CP eigenvalue, +1 (-1) for CP even (odd) A=0

4  = (Belle) 0.56 (BaBar) Principle of TCPV measurement CP-side 1.Fully reconstruct one B-meson which decays to CP eigenstate electron (8GeV) positron (3.5GeV)  (4S) resonance B1B1 B2B2 ++ -- K S/L J/ 

5  = (Belle) 0.56 (BaBar) Principle of TCPV measurement CP-side Flavor tag and vertex reconstruction 1.Fully reconstruct one B-meson which decays to CP eigenstate 2.Tag-side determines its flavor 3.Proper time (  t) is measured from decay-vertex difference (  z) electron (8GeV) positron (3.5GeV)  (4S) resonance B1B1 B2B2 ++ -- K+K+ --  ++ -- K S/L J/   z ~ 200  m (Belle) B0B0 B0B0 _

6 KEKB : the highest luminosity in the world 3.5 GeV e +  8.0 GeV e  e + e    (4S) with  = mrad crossing angle Located in Tsukuba, Japan L peak = (1.65  )/cm 2 /sec  ~ 1M BB pairs/day integrated luminosity = 0.63 /ab 532 M BB pairs analysis are shown, today _ _ Belle detector

7 International Collaboration: Belle 13 countries, 55 institutes, ~400 collaborators 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. Nat’l Kaoshiung Normal 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 Utkal U. VPI Yonsei U.

8 Belle Detector K L  detector 14/15 layer RPC+Fe Electromagnetic Calorimeter CsI(Tl) 16X 0 Aerogel Cherenkov Counter n = 1.015~1.030 Si Vertex Detector 4-layer DSSD TOF counter 3.5 GeV e + Central Drift Chamber momentum, dE/dx 50-layers + He/C 2 H 6 charged particle tracking K/  separation B vertex Muon / K L identification ,  0 reconstruction e +-, K L identification 8.0 GeV e -

9 B 0  J/  K L J/    Event Display of B 0  J/  K L

10 B 0  J/  K 0 : 532 M BB pairs B 0  J/  K S B 0  J/  K L Nsig = 7482 Purity 97 % CP odd Nsig = 6512 Purity 59 % CP even p KL information is poor  lower purity Belle preliminary 00 _

11  = (Belle) 0.56 (BaBar) Principle of TCPV measurement CP-side Flavor tag and vertex reconstruction 1.Fully reconstruct one B-meson which decays to CP eigenstate 2.Tag-side determines its flavor 3.Proper time (  t) is measured from decay-vertex difference (  z) electron (8GeV) positron (3.5GeV)  (4S) resonance B1B1 B2B2 ++ -- K+K+ --  ++ -- K S/L J/   z ~ 200  m (Belle) B0B0 B0B0 _

12 R : detector resolution w : wrong tag fraction (misidentification of flavor)  (1-2w) quality of flavor tagging They are well determined by using control sample D * l  D (*)  etc… S = 0.65 A = 0.00 B 0 tag _ _ -  CP sin2  1 Mixing of D * l Good tag region (OF-SF)/(OF+SF)  t| (ps)

13 B 0  J/  K S, K L B 0  J/  K S B 0  J/  K L Asym. = -  CP sin2  1 sin  m  t CP odd :  CP =-1 CP even :  CP =+1 Belle preliminary B 0 tag _ _ 00 Sig Sig+BG Belle preliminary

14 B 0  J/  K S, K L B 0  J/  K S B 0  J/  K L CP odd :  CP =-1 CP even :  CP =+1 Belle preliminary B 0 tag _ _ 00 Sig Sig+BG sin2  1 = ±0.038 A = ±0.028 sin2  1 = ±0.057 A = ±0.033 stat error Belle preliminary

15 B 0  J/  K S, K L B 0  J/  K S B 0  J/  K L Asym. = -  CP sin2  1 sin  m  t sin2  1 = ±0.038 A = ±0.028 sin2  1 = ±0.057 A = ±0.033 CP odd :  CP =-1 CP even :  CP =+1 Belle preliminary B 0 tag _ _ 00 stat error

16 B 0  J/  K S B 0 tag _ 0 B 0  J/  K L B 0 tag _ 0 _ B 0  J/  K 0 : combined result Asym. = -  CP sin2  1 sin  m  t sin2  1 = ±0.038 A = ±0.028 sin2  1 = ±0.057 A = ±0.033 stat error

17 B 0  J/  K 0 : combined result sin2  1 = ±0.031 (stat) ±0.017 (syst) A = ±0.021 (stat) ±0.014 (syst) previous measurement sin2   =  (386 M BB pairs) B 0 tag _ 532 M BB pairs _ _ Belle preliminary

18 Constraint on the Unitarity Triangle  1 =20 o  1 =70 o ? ? Intrinsic ambiguity still remains … 2  1   -2  1

19 B 0  D[K S  +  - ]h 0 (h 0 =  0, ,  ) _ M 2 (K S   ) M 2 (K S   ) f -+ M 2 (K S   ) M 2 (K S   ) f +- hep-ex/ submitted to PRL Time-dependence of Dalitz gives sin2  1 and cos2  1 sin2  1 = 0.78 ±0.44(stat) ±0.22(syst) cos2  1 = 1.87 (stat) (syst)  0.53  0.32 Negative cos2  1 is disfavored at 98.3% C.L.

20 Constraint on the Unitarity Triangle  1 =20 o  1 =70 o ? ? (^_^)  1 = 20.0 o ± 1.3 o ( Belle data only ) Time-dependent Dalitz analysisof B 0  D[ K S     ]h 0 hep-ex/ submitted to PRL Disfavored at 98.3% C.L. _

21 KEKB Integrated luminosity as a function of time 1 /ab  1 ~1 o B 0  J/  K S 0 B 0  J/  K L 0 Based on 532 M BB sin2  1 = ±0.031 (stat) ±0.017 (syst) A = ±0.021 (stat) ±0.014 (syst)  1 = 20.0 o ± 1.3 o _ Summary

22 Excellent combined results will be shown by next speaker, K. George Summary The  1 is one of the most precise SM parameter The sin2  1 is good SM anchor point for new physics hunting Tree  Penguin KEKB + PEP-II Exceeds 1 /ab ! KEKB PEP-II

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24 History of sin2  1 at Belle 6.2 /fb : 0.45± ±0.60 (J/  K S ), -1±0.89 (J/  K L ) 29.1 /fb : 0.99± ±0.20 (J/  K S ), 1.31±0.23 (J/  K L ) 78/fb : 0.72±0.07 (combined w/  (2S)Ks etc.) 0.73±0.10 (J/  K S ), 0.78±0.17 (J/  K L ) 140 /fb : 0.73±0.05 (combined w/  (2S)Ks etc.) 0.67±0.08 (J/  K S ), 0.77±0.13 (J/  K L ) 357 /fb : 0.65±0.04 (J/  K 0 combined) 0.67±0.05 (J/  K S ), 0.62±0.07 (J/  K L ) 492 /fb : 0.64± ±0.04 (J/  K S ), 0.64±0.06 (J/  K L ) Stat. error only

25 Systematic errors of B 0  J/  K 0 Sin2  1 A Vertexing Flavor tagging  t Resolution Physics parameters Possible fit bias BG fractions (J/  K S ) BG fractions (J/  K L ) BG  t Tag-Side interference total

26 Misalignment Misalign DSSDs in MC to reproduce IP resolution (15um shift, 0.15mrad)

27 Tag Side Interference Interference between CKM-favored and CKM-suppressed B  D transitions in the tag-side. Estimated by pseudo-experiments whose parameters are obtained from B 0  D*lnu samples No interference for semi-leptonic decay in tag side (It was included till last year)

28 Flavor Tag NIM A 533, 516 (2004)

29 Wrong tag probability r = 1-2w Estimate w from time-dependent B0-B0 mixing NIM A 533, 370 (2004) for resolution