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Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 20041 Search for the Lepton Flavor Violating Decay e in the MEG Experiment Shuei YAMADA ICEPP, University of Tokyo for the MEG collaboration Slide 2 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 20042 Contents Physics Motivations Event Signature The MEG Experiment Schedule Summary Slide 3 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 20043 Physics Motivation e : Lepton Flavor Violating process Forbidden in the SM Sensitive to new physics SUSY GUT SUSY Seesaw Sensitivity down to ~10 -14 Present limit Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200412 590MeV > 1.8mA > 150days/year PSI Proton Cyclotron Slide 13 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200413 + Beam @ E5 + / e + separator The MEG detector 590MeV Primary Proton Quadruple magnets Beam Transport Solenoid Bending magnets Degrader E5 area @PSI + Beamline target Intense focused DC muon beam 10 7~8 /sec, ~ 2cm Surface muon beam : 28MeV/c Slide 14 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200414 COBRA Spectrometer COnstant Bending RAdius Independent of emission angles e + momentum easily used at trigger level reconstruction flat acceptance Michel e + swept out quickly Reduce # of hits on the chamber Solenoid with a gradient filed Slide 15 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200415 COBRA is already working @ PSI !! Succeeded full excitation (Apr. 2004) Gradient field profile @ 200A (full excitation : 360A) Good agreement w/ calculation ! Slide 16 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200416 Drift Chamber Conventional DC Less materials to reduce e + annihilation Slide 17 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200417 800 liter Liquid Xenon scintillator high light yield : 75% NaI(Tl) fast response : 45ns decay time good uniformity 850 2 PMTs Facing inwards like Super-Kamiokande Directly soaked in LXe R&D with prototype Performance LXe purification Operation @ ~165K Construction starts this year LXe Scintillation -ray Detector Slide 18 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200418 100 liter Prototype 70L fiducial volume 228 2 PMTs To verify performance & operation beam Slide 19 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200419 Task of the 100L Prototype Detector operation Refrigerator, monitoring system, electronics, LXe purification Detector performance resolution 228 2 PMTs Hamamatsu R6041Q Soaked directly into LXe Operation @ 165K Long term stability Slide 20 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200420 LXe Purification Scintillation light absorbed by H 2 O & O 2 Achieved absorption length > 100cm (45MeV Photon-positron timing correlation < 20ns Photon-positron opening angle ~ 180deg."> Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200436 Electronics & Trigger Domino Ring Sampling chip Waveform digitizer sampling up to 4.5GHz 10ch x 1024bins Readout speed up to 100MHz Expected trigger rate : 20Hz Photon energy >45MeV Photon-positron timing correlation < 20ns Photon-positron opening angle ~ 180deg. Slide 37 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200437 Purification System Xenon extracted from the chamber is purified by passing through the getter. Purified xenon is returned to the chamber and liquefied again. Circulation speed 5-6cc/minute Enomoto Micro Pump MX-808ST-S 25 liter/m Teflon, SUS Gas return To purifier Circulation pump Slide 38 Shuei YAMADA, ICEPP, University of Tokyo @ tau04 Nara, Sep. 15, 200438 Single Event Sensitivity B( e )=1/{N T ( /4 ) e sel }=4.5x10 -14 N =0.25x10 8 /sec, T=2.6x10 7 sec, /4 =0.09, e =0.90, =0.6 and sel =0.7