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f 1 measurements with tree-level processes at Belle

f 1 measurements with tree-level processes at Belle. O. Tajima (KEK) Belle collaboration ICHEP06 July 28, 2006. Kobayashi-Maskawa Phase. l ~ 0.22. CP violation is due to a complex phase in quark mixing matrix. CP violation parameters ( f 1 , f 2 , f 3 ) = ( b , a , g ). B 0.

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f 1 measurements with tree-level processes at Belle

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  1. f1 measurements with tree-level processesat Belle O. Tajima (KEK) Belle collaboration ICHEP06 July 28, 2006

  2. Kobayashi-Maskawa Phase l ~ 0.22 CP violation is due to a complex phase in quark mixing matrix CP violation parameters (f1, f2, f3) = (b, a, g )

  3. B0 _ fCP _ _ _ c q p _ J/y _ d b b B0 c t w B0 B0 _ B0 w w t s b d d K0 d _ G(Dt ; B0J/yK0) -G(Dt ; B0J/yK0) = _ A G(Dt ; B0J/yK0) +G(Dt ; B0J/yK0) CP = -xcpsin2f1 sin(DmDt) + A cos (DmDt) Direct CPV (A = -C) Mixing induced CPV xCP: CP eigenvalue, +1 (-1) for CP even (odd) sin2f1 measurement V*td V*td A=0

  4. Principle of TCPV measurement CP-side m+ J/y m- (4S) resonance B1 electron (8GeV) KS/L positron (3.5GeV) B2 bg = 0.425 (Belle) 0.56 (BaBar) • Fully reconstruct one B-meson which decays to CP eigenstate

  5. _ B0 Principle of TCPV measurement CP-side m+ J/y m- (4S) resonance B1 electron (8GeV) KS/L B0 positron (3.5GeV) nm B2 p- bg = 0.425 (Belle) 0.56 (BaBar) K+ p- Flavor tag and vertex reconstruction Dz ~ 200mm (Belle) m+ • Fully reconstruct one B-meson which decays to CP eigenstate • Tag-side determines its flavor • Proper time (Dt) is measured from decay-vertex difference (Dz)

  6. _ 532 M BB pairs analysis are shown, today KEKB : the highest luminosity in the world Located in Tsukuba, Japan Belle detector 3.5 GeV e+8.0 GeV e- e+e-(4S) with bg = 0.425 22 mrad crossing angle Lpeak= (1.651034)/cm2/sec  ~ 1M BB pairs/day integrated luminosity = 0.63 /ab _

  7. 13 countries, 55 institutes, ~400 collaborators International Collaboration: Belle 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. 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 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 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

  8. Belle Detector K/pseparation • , p0 reconstruction e+-, KLidentification Aerogel Cherenkov Counter n = 1.015~1.030 Electromagnetic Calorimeter CsI(Tl) 16X0 3.5 GeV e+ TOF counter K/pseparation charged particle tracking 8.0 GeV e- Central Drift Chamber momentum, dE/dx 50-layers + He/C2H6 B vertex Muon / KLidentification Si Vertex Detector 4-layer DSSD KLm detector 14/15 layer RPC+Fe

  9. Event Display of B0 J/y KL B0 J/y KL J/y  m+m-

  10. _ B0 J/y K0 : 532 M BB pairs B0 J/y KS 0 B0 J/y KL 0 Nsig = 7482 Purity 97 % CP odd Nsig = 6512 Purity 59 % CP even pKL information is poor  lower purity Belle preliminary

  11. _ B0 Principle of TCPV measurement CP-side m+ J/y m- (4S) resonance B1 electron (8GeV) KS/L B0 positron (3.5GeV) nm B2 p- bg = 0.425 (Belle) 0.56 (BaBar) K+ p- Flavor tag and vertex reconstruction Dz ~ 200mm (Belle) m+ • Fully reconstruct one B-meson which decays to CP eigenstate • Tag-side determines its flavor • Proper time (Dt) is measured from decay-vertex difference (Dz)

  12. B0 tag (OF-SF)/(OF+SF) Mixing of D*ln Good tag region _ _ B0 tag B0 tag |Dt| (ps) -xCPsin2f1 B0 tag S = 0.65 A = 0.00 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*ln, D(*)p etc…

  13. Belle preliminary Sig Sig+BG _ _ B0 tag B0 tag Belle preliminary B0J/y KS , KL B0 J/y KS 0 B0 J/y KL 0 B0 tag B0 tag CP odd : xCP=-1 CP even : xCP=+1 Asym. = -xCPsin2f1sinDmDt

  14. Belle preliminary Sig Sig+BG _ _ B0 tag B0 tag Belle preliminary B0J/y KS , KL B0 J/y KS 0 B0 J/y KL 0 B0 tag B0 tag CP odd : xCP=-1 CP even : xCP=+1 sin2f1= +0.643 ±0.038 A = - 0.001 ±0.028 sin2f1= +0.641 ±0.057 A = +0.045 ±0.033 stat error stat error

  15. Belle preliminary _ _ B0 tag B0 tag B0J/y KS , KL B0 J/y KS 0 B0 J/y KL 0 B0 tag B0 tag CP odd : xCP=-1 CP even : xCP=+1 Asym. = -xCPsin2f1sinDmDt sin2f1= +0.643 ±0.038 A = - 0.001 ±0.028 sin2f1= +0.641 ±0.057 A = +0.045 ±0.033 stat error stat error

  16. _ B0 tag B0 tag B0 tag _ _ B0 tag B0 tag B0 J/y K0 : combined result B0 J/y KS 0 B0 J/y KL 0 B0 tag Asym. = -xCPsin2f1sinDmDt sin2f1= +0.643 ±0.038 A = - 0.001 ±0.028 sin2f1= +0.641 ±0.057 A = +0.045 ±0.033 stat error stat error

  17. _ 532 M BB pairs B0 tag _ B0 tag B0 J/y K0 : combined result previous measurement sin2f1= 0.652  0.044 (386 M BB pairs) _ sin2f1= 0.642 ±0.031 (stat) ±0.017 (syst) A = 0.018 ±0.021 (stat) ±0.014 (syst) Belle preliminary

  18. Constraint on the Unitarity Triangle Intrinsic ambiguity still remains … 2f1 p-2f1 ? f1=70o f1=20o ?

  19. _ f-+ f+- M2(KSp-) M2(KSp-) M2(KSp+) sin2f1 = 0.78 ±0.44(stat) ±0.22(syst) cos2f1 = 1.87 (stat) (syst) M2(KSp+) +0.40 +0.22 -0.53 -0.32 hep-ex/0605023 submitted to PRL B0  D[KSp+p-]h0 (h0=p0,w,h) Time-dependence of Dalitz gives sin2f1 and cos2f1 Negative cos2f1 is disfavored at 98.3% C.L.

  20. Constraint on the Unitarity Triangle _ Time-dependent Dalitz analysisof B0  D[ KSp+p- ]h0 hep-ex/0605023 submitted to PRL ? f1=70o f1=20o Disfavored at 98.3% C.L. ? (^_^) f1= 20.0o± 1.3o (Belle data only)

  21. B0 J/y KS B0 J/y KL 0 0 KEKB Integrated luminosity as a function of time _ Based on 532 M BB sin2f1= 0.642 ±0.031 (stat) ±0.017 (syst) A = 0.018 ±0.021 (stat) ±0.014 (syst) f1 = 20.0o ± 1.3o Summary 1 /ab df1~1o

  22. Summary KEKB + PEP-II Exceeds 1 /ab ! KEKB PEP-II The f1 is one of the most precise SM parameter The sin2f1 is good SM anchor point for new physics hunting Tree  Penguin Excellent combined results will be shown by next speaker, K. George

  23. backup

  24. History of sin2f1 at Belle • 6.2 /fb : 0.45±0.45 0.22±0.60 (J/yKS) , -1±0.89 (J/yKL) • 29.1 /fb : 0.99±0.14 0.81±0.20 (J/yKS) , 1.31±0.23 (J/yKL) • 78/fb : 0.72±0.07 (combined w/ y(2S)Ks etc.) 0.73±0.10 (J/yKS) , 0.78±0.17 (J/yKL) • 140 /fb : 0.73±0.05 (combined w/ y(2S)Ks etc.) 0.67±0.08 (J/yKS) , 0.77±0.13 (J/yKL) • 357 /fb : 0.65±0.04 (J/yK0 combined) 0.67±0.05 (J/yKS) , 0.62±0.07 (J/yKL) • 492 /fb : 0.64±0.03 0.64±0.04 (J/yKS) , 0.64±0.06 (J/yKL) Stat. error only

  25. Systematic errors of B0J/yK0

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

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