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τ ｐｈｙｓｉｃｓ　ａｔ　Ｂｅｌｌｅ

τ ｐｈｙｓｉｃｓ　ａｔ　Ｂｅｌｌｅ. PRESENT status 　ａｎｄ　 FUTURE prospect. H ． Hayashii Nara ， Japan Contents 1 ． Tau physics at Belle 2 ． KEKB and Belle detector ３． Present status ４． Future Prospect. International Workshop on BESIII Detector. τlepton Heaviest lepton ... Sensitive to NewPhysics

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τ ｐｈｙｓｉｃｓ　ａｔ　Ｂｅｌｌｅ

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  1. τｐｈｙｓｉｃｓ　ａｔ　Ｂｅｌｌｅ PRESENTstatus　ａｎｄ　FUTUREprospect H．Hayashii Nara，Japan Contents 1．TauphysicsatBelle 2．KEKBandBelledetector ３．Presentstatus ４．FutureProspect International Workshop on BESIII Detector ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  2. τlepton • Heaviest lepton ... Sensitive to NewPhysics • Only lepton that can decay to hadron ..…. • Less known compared to e and μ • No of tau`s ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  3. τｐｈｙｓｉｃｓ　at Belle(Present status) We present 3 topics a)ｄｅｃａｙ() b)tauEDMmoments(CP violation in lepton sector) c) rare(forbidden) decay(Lepton Flavor Violation) c-1) c-2) neutrinoless 3 Chargeddecays Results are preliminary +‘forbidden` decay ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  4. IntroductiontoKEKB／Belle • Withthegoal　ｏｆ　measuringCP－violatingasymmetry　ｉｎ Bmesondecays， －construction　ｏｆ　KEKBasymmetriccolliderand　ｔｈｅ　Belle detectorwasstartedin　Ａｐｒｉｌ　１９９４，　andwascompleted inDecember　１９９８． －　Ｂｅｌｌｅ　Physics　ｒｕｎ　wasstartedJune　１９９９． • Luminosity　Ｇｏａｌ：　 　　ｔｏ　producemorethan１０８ＢＢ　ｐａｉｒｓ／ｙｅａｒ（＝１００／ｆｂ／ｙｅａｒ） • Ｓａｍｅ　ａｍｏｕｎｔ　ｏｆ　ｔａｕ－ｐａｉｒｓ(108ττ）　ａｒｅ　ｐｒｏｄｕｃｅｄ． －＞　tau－ｐｈｙｓｉｃｓ：　　ｉｍｐｏｒｔａｎｔ　ｔａｒｇｅｔ　ａｔ　Ｂｅｌｌｅ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  5. KEKB : Asymmetric e+e- collider • CM energy : 10.580 GeV at(4S) • Two separate rings : • e+ (LER:3.5GeV) • e- (HER:8.5GeV) • Luminosity • Target : 1034 cm-2s-1 • Achieved : 4.5x1033 cm-2s-1 • Design Parameters • 3016 m circumference • 5120 RF buckets (2ns) • 2.6 A for e+, 1.1 A for e- • 22 mrad crossing angle at IP • sy 3mm, sx 100mm • History • First collision : Jan. 1999 • Physics run : since June 1999 KEKB accelerator Belle detector ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  6. KEKB performance 2001／7/29  225pb-1/day Integrated luminosity/day  32.8fb-1 Total accumulated luminosity ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  7. SVD CDC ACC TOF CsI KLM Solenoid Belle Detector • Event reconstruction • Charged tracks  Silicon Vertex Detector (SVD)  Central Drift Chamber (CDC) • Electrons and photons •  Electromagnetic Calorimeter (CsI) • Vertexing •  SVD Particle identification K/p separation  CDC : dE/dx  Aerogel Cherenkov Counter (ACC)  Time of Flight Counter (TOF) electron identification  ECL KL and muon identification  KL and muon detector (KLM) ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  8. Ｈｏｗ Ｂｅｌｌｅ data look like B0 J/+Ks   m+m- + Belle r-f view in SVD y-z view near IP ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  9. τ-→πーπ０ντdecay ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  10. has largest Branching fraction This is a trial to make a precision physics at Belle ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  11. ●Wefirstmeasure (from ratio) ratio： cancelmanysystematicsinLumi．，trackingeff． canbeusedforBrmeas．ofotherdecaymode →DetermineNττ， →DetermineNhπ０ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  12. Ｇｅｎｅｒｉｃ　tau－ｐａｉｒ　selection • Signature ofττ event：lowmulti．，missingmom． • B.G. : • Requirement: Cuts→As loose as possible Criteria: (Bhabha，μμγrej．） (rad－Bhabha，two－photonrej．) ● (bhabharej．） ● (conti．，BBreject．) One hemi The other hemi ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  13. MissingmassvsTheta＿missing Data MC( ) twophoton MM(GeV) MM(GeV) rad．bhabha ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  14. Background　６．８％　 ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  15. π0 Ｖｅｔｏγ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  16. Pi0 momentum &Theta(τ±→ｈ±π０ντ) Ｐπ０（Ｌａｂ） θπ０（Ｌａｂ） ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  17. Charged Particle `sMomentum &Theta(τ±→ｈ±π０ντ) Ｐｈ±（Ｌａｂ） θｈ±（Ｌａｂ） ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  18. ππ０mass Linear　ｓｃａｌｅ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  19. ππ０mass Ｌｏｇ　ｓｃａｌｅ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  20. Br ( ) Observed event with 4.42/fb data τ-pair selection hπ selection Current systematic errors Can be improved with Large data ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  21. Systematic Error Many errors are canceled in the ratio (stat.) (sys.) Ｎｕｍｂｅｒｓａｒｅ　ｐｒｅｌｉｍｉｎａｒｙ． ｓｙｓｔｅｍａｔｉｃｓ　ｕｎｄｅｒ　ｉｎｖｅｓｔｉｇａｔｉｏｎ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  22. ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  23. b) τElectroDipole Moment（EDM) 　ｄτ • EDM：CPViolating observable • AnyCPVatτproductionvertexcanbeparametrizedbyEDM • current upper limit : |d|< 3.1  10–16 ecm (LEP L3 ; ee  ) |Re(d)|< 4.6  10–16 ecm, |Im(d)| < 1.8  10–16 ecm (ARGUS) ←CP violating effective lagradian ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  24. candidate – e+ e– e+ Belle EDM analysis • 28.9　／fb • Use8combinations • Criteria 1－1prong，nosingleγ barrelpart，highptrack e,μ，π：probability＞0.95 • 1.18Mevents ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  25. Selecteddata e μ ρ π ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  26. Selecteddata μ e ρ π ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  27. Ｏｂｓｅｒｖａｂｌｅ for EDM measurement ←CPviolating terms Ｕｓｅ Optimal observable[PRD45,2405(1992)] • MaximumSensitivity • Meanvalue→prop．toEDM • Ambiguity of taudirection -> amplitude is avaraged • Most probable spin direction->determined from tau and decay daughter ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  28. Ｄｏｔ：exp.ｄａｔａ Ｈｉｓｔｏｇｒａｍ：ＭＣ Back.：ｂｌｕｅ Observabledistribution μρ πρ ORe=0.00600.0105 OIm= –0.0130.008 ORe=0.00520.0041 OIm= 0.0220.022 ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  29. ORe vs Re(d) from MC EDMvsObservable Inorder　ｔａｋｅ　intoaccountdetector　ｅｆｆｅｃｔ，coefficientsaredetermined　ｂｙ　ＭＣ Highsensitivity　ｆｏｒ　hadronicdecay ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  30. EDMresults Errorsdominated　ｂｙ　statistics Weightedmean ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  31. EDM　ｒｅｓｕｌｔｓ（２） 28.9／fb ｄａｔａ current upper limit : |d|< 3.1  10–16 ecm (LEP L3 ; ) |Re(d)|< 4.6  10–16 ecm, |Im(d)| < 1.8  10–16 ecm (ARGUS) • Ｏneorder　ｏｆ　magnitude　ｉｍｐｒｏｖｅｍｅｎｔ • Results　ａｒｅ　ｌｉｍｉｔｔｅｄ　ｂｙ statistics • Im: comparable to WDM results at LEP c.f.　ＷＤＭ（Ｗｅａｋ　ＤｉｐｏｌｅＭｏｍｅｎｔ)　ｌｉｍｉｔ: • Next Target ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  32. c）　Rare`Forbidden` decay(LFV)τ→μγ ● ● ● ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  33. τ→μγ： analysis based on 21/fb data Criteria • 2－prong+ ≧1γ • Signal side • Tag side track is not muon • Tau +missing ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  34. Signal Box Ｄａｔａ 21/fb ３　candidates　ｉｎ　ｔｈｅ　ｓｉｇｎａｌ　Box ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  35. Backgroundevaluation ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  36. Background estimation　ａｎｄ　ｕｐｐｅｒ－ｌｉｍｉｔ • B.G. :tacking into account and B.G. inthesignal boxis estimated from data (use muon-ID ineff. Value) to be 5.9event • Efficiency　＝　　9.4％ ＃data(＃Ｂ．Ｇ．） • ＃ofsignal　ａｔ　95％ C.Ｌ． ＝３．５ｅｖ 　(Bayesian method) ↓ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  37. AchievableSensitivity • High luninosity ＋ • Include　Ｅｎｄｃａｐ(x1.35) • Ｃｕｔｓ　ｏｐｔｉｍｉｚａｔｉｏｎ(x1.30) • Improve　　　　　　ｒｅｓ．(x1.6) • (use　ＴＯＦ／ACC　ｉｎｆｏ．） Present condition ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  38. LFV: Ｎｅｕｔｒｉｎｏless 3 charged decay @90％C.L. ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  39. Neutrinoless 3 charged decay :improve 2 order of magnitude. MarkII 90%C.L. Our target Br=10-7-10-8 ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  40. Outlooks • KEKB/Belle achieveda luminosity of：　4.5x1033cm－1s－1 • Belle accumulated 33 fb-1(30x106 ττevent) data • 10 times more data in next 5 years • Our PHYSICS targets are • Precise measurement of spectrum function in • Limit／finda Rear Decays ofτin the range10-7—10-8 • Measure EDM target 10－17-10-18 ecm • CPV in • Tau decay to Kaon -> ms • Michel parameters • ・・・・・ ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  41. KEKB : Plan • Limiting factors on KEKB : • beam current limit to avoid arcing at masks and bellows • e+ blow up due to photoelectron cloud by synchrotron light • beam blow up due to beam-beam effect • Near future : • more tunings • replacing masks and bellows  more bunch current • Future possibilities : • Reduce photoelectron effect (1) Antechambers for e+ ring (2) Charge swap : e-(8.0GeV)+e+(3.5GeV)  e-(3.5GeV)+e+(8.0GeV) • Crab collision ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  42. τｐｈｙｓｉｃｓ　ａｔ　ＢｅｌｌｅBESIII workshop 2001Oct13-15，Beijing，China ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

  43. The Belle Collaboration World-Wide Activity Involving 50 Institutions ~300 members ＢＥＳＩＩＩ　ｗｏｒｋｓｈｏｐ　２００１ｏｃｔ１３－１５

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