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KEK 　高エネルギ , ce^ Tokyo 東京

The BELLE Experiment. KEK 　高エネルギ , ce^ Tokyo 東京. Collaboration. The Experiment. The Physics. Overview of Newest Results. BB threshold. KEKB Collider. e -. e +. L peak = 1.2 x10 34 cm -2 sec -1 design = 10 34 cm -2 sec. 8GeV. 3.5GeV. = 0.425. bg. B-Factory

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KEK 　高エネルギ , ce^ Tokyo 東京

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  1. The BELLE Experiment KEK　高エネルギ, ce^ Tokyo 東京 Collaboration • The Experiment • The Physics • Overview of Newest Results

  2. BB threshold KEKB Collider e- e+ Lpeak=1.2 x1034cm-2sec-1 design=1034cm-2sec 8GeV 3.5GeV = 0.425 bg B-Factory (on the 4s resonance) BB threshold

  3. SVD The BELLE Detector

  4. Difference SVD1.6 and SVD2.0 Rbeampipe 15 mm Rbeampipe 20 mm Rlayer 1 20 mm Rlayer 1 30 mm Routside 88 mm Routside 60 mm 6+12+18+18=54 Ladders 8+10+14=32 Ladders SVD1 SVD2

  5. Vienna R/O & Trigger Electronics R-Z Trigger R-PHI Trigger 2 x 18 FADCTF 24 input OR and analog signal input from VATA Multi event buffer L1.5 Trigger outputs Fast connection to PCI bus Trigger outputs

  6. Deterministic annealing filtersfor robust vertexing in BELLE falsely rejected rightly accepted rightly rejected falsely accepted association weight association weight • KVF tends to use more bad measurements, and also use less good measurements • DAF uses more measurements in total, moderately weighted

  7. performance overviewtag-side reconstruction (MC) best resolution of DAF: • 107.7 ± 1.43 µm best resolution of KVF: • 115.5 ± 1.59 µm DAF resolution at its highest eff.: • 111.5 ± 1.34 µm @ 6903 KVF resolutionat its highest eff.:: • 128.1 ± 1.61 µm @ 6306 Efficiency gain of appox. 6 – 16% Precision gain between: 16.6 ± 2.09 µm and 4 ± 2.08 µm • initial KVF fit, cut on χ² prob < 1% • histogram range: [- 600; +600] µm

  8. dsb u Vud Vus Vub c Vcd Vcs Vcb t Vtd Vts Vtb B0->ππ B0->rπ B0->J/Ks B0->fKs B0->D(*) D(*) B0-> D*π B0->D*r B->DCPK The Physics of BELLE CKM-Matrix {i=1,k=3}: Vub*Vud+Vcb*Vcd+Vtb*Vtd = 0 Vub*Vud Vcb*Vcd Vtb*Vtd Vcb*Vcd  + 1 + = 0 -(rih) -(1-rih) rih unitarity triangle rih Vtb*Vtd Vcb*Vcd f2 Vub*Vud Vcb*Vcd (a) f3 f1 1 (g) (b) 0 self-consistent if SM correct

  9. Principle of f1-Measurement with B  J/y Ks Flavor-tag decay (B0 or B0 ?) J/ e fCP e t=0 KS z B - B B + B more B’s more B’s t z/(cβγ)

  10. Overview of New Results • collected 200/fb integrated luminosity until March 2004 • corresponding to 190 millionen B-events sin2f1 (Belle 2003, 140 fb-1) =0.733±0.057±0.028 sin2f1 (BaBar 2002, 81 fb-1)=0.741±0.067±0.033 CP = -1 sample sin2f1 = 0.73±0.06 CP = +1 sample sin2f1 = 0.80±0.13

  11. New Physics in B f Ks ? • B f Ks theoretically clean • A = -0.15 ± 0.29 ± 0.07 • sin2f1eff= –0.96 ± 0.50 • 3,5 s deviation from precision result! SM predicts same CPV in b ccs and sqq. New physics may deviate CPV in b ccs from sqq SM penguin New process w/ different CP phase f + Hint of new physics

  12. Comparison of several channels Fit sin2f1 @ 152M BB B0 fKS B0K+K-KS B0h’KS BfCP(sqq) decay vertices are reconstructed using K- or p-track pair.

  13. New Charmonium Resonance ? • found in channel B±-> K±(J/Yp+p-) • mass: 3871.8±0.7±0.4 MeV • natural width < 3.5 MeV @ 90% C.L. • 34.4±6.5 events, statist. significance 8.6s Belle 304M B’s Y(2S) M(J/ Yp+p-) - M(J/ Y) GeV

  14. Vienna Analysis - Motivation • |Vub| can be measured in B  pln • requires knowledge of form factor fB(q2) • analoguous form factor fD(q2) • can be measured in D  pln • ratio fB /fD is theoretically better • known than absolute value •  reduction of theoretical error

  15. K p recoil p K recoil mass- / vertex fit „inverse“ fit p e/µ Method of „full inclusive reconstruction“ additional primary mesons 3.5 GeV e+ e- 8 GeV D* D* p p D D recoil n K p p p

  16. Overview of Vienna Charm Analyses • What we are going to do with the data: • semileptonic form factors • f+D(q²) for D  pln • may be used to reduce systematic • error on f+B(q²) for |Vub| measurement • high resolution q² distribution for D  Kln • cross sections for D*D*(np/K) • various channels: D*D*p, D*D*pp, D*D*KK, D*D*ppp, D*D*pppp, D*D*KKpp • inclusive D decays BR • various channels, mostly poorly measured: • D  K± + anything • D  e± + anything • D  µ± + anything • D  f + anything • Statistics after bkg subtraction: • D  Kln: 417 ± 20 events • (4.8%stat 1.1%bkgsyst) • D  pln: 45 ± 6 events • (12.8%stat 5.4%bkgsyst) reconstructed neutrino mass Kln REAL DATA mn² / GeV² pln mn² / GeV²

  17. form factor f+(q²) arbitrary normalization single-pole model single-pole model pln Analysis: q² distribution K/pln Analysis q² signal & background • shapes of bkg derived from MC except for non-D bkg (from D* side-band data) • bkg subtracted according to bkg measurement presented before • efficiency correction slightly rising with q² for K, rather flat for p Kln REAL DATA preliminary D pln non-D bkg MC DATA D Kln corrected q² distribution D  hadronic REAL DATA pln Kln preliminary q² / GeV² q² / GeV² • our advantage: comparatively clean, high resolution sample pln q² / GeV²

  18. Ereignisrekonstruktion in C++ bei BELLE PDA Seminar 11/02 Laurenz Widhalm

  19. Spares

  20. B0 J/y Vcb KS V*2 td B0 B0 V* J/y Vcb td Vtb KS V* Vtb td Prinzip der f1-Messung mittels B  J/y Ks • keine theoretische Unsicherheit • experimentell sauber • „goldener Kanal“ sin2f1 (NEW World Av.) =0.736±0.049

  21. Neue Physik in B f Ks ? • BaBar Resultat von 2002: • sin2f1eff= –0.18 ± 0.52 • Resultat 2003: • sin2f1eff= +0.45 ± 0.44 • Grund für Verschiebung ist eine • 1s statistische Fluktuation 70 ± 9 events Erst die Zukunft, mit mehr Statistik (und eventuell weiter verbesserter Analyse) wird die Antwort bringen! sin2f1 (NEW World Av.) =0.736±0.049

  22. q q Neue Charmonium Resonanz ? • Interpretation: • Masse gerade an der D0D*0 threshold • lose gebundenes “molecular charmonium”, oder ein Y(13D2) Zustand? • Ersteres in der Literatur diskutiert seit 1975: • ausgelöst durch komplizierte Struktur vons(e+e- ->hadrons) bei SPEAR • M. Bander, G.L. Shaw, P. Thomas, PRL 36, 695 (1976) • M.B. Voloshin, L.B. Okun JETP Lett. 23, (1976), Pisma Zh.Eksp.Teor.Fiz.23, 369 (1976) • A.De Rujula, H.Georgi, S.L.Glashow, PRL 38 (1977) • WW beschrieben durch p-Austausch gibt attraktive Kraft für DD*, BB* • N.A. Tornqvist, PRL 67, 556 (1991), Z.Phys. C61, 525(1994) • A.V. Manohar, M.B. Wise,Nucl.Phys. B339, 17(1993) Diquark Model (Qq) are colored D0D*0 molecule q A different idea from that time: q Q Q Q Q Stronger binding Loose binding Decays to (QQ)+(light mesons) via quark rearrangement which suppresses the width. “Discovery of the signal is very recent. Belle is working on this channel but is not ready to present any results” (Lepton-Photon 2003) sin2f1 (NEW World Av.) =0.736±0.049

  23. Next: f2(α)from B|fcp>=p+p- Vub p+ B0 p- + V*2 V2 td ub V* Vub p- Vtb td B0 B0 p+ Vtb V* td

  24. Find: 78°≤ f2 ≤ 152° (95% C.L.) insensitive to d Indirect constraints (CKM fitter group): 78.3°≤ f2 ≤ 121.6° (95% C.L.)  consistent Constraints on the CKM angle φ2 (α) • Sππ, Aππ depend on 4 parameters: f2, f1[21.3°-25.9°], |P/T|[0.15-0.45], d -> plot confidence contours in (f2, d) for various |P/T| e.g. |P/T|=0.3 f1 =23.5° f2 d

  25. office of a Japanese physicist (complete with camping bed)

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