1. The MEG Experiment T. Mori for the MEG Collaboration

2. MEG Physics Clear signal of New Physics Never occurs in the Standard Model SUSY GUT promising Unification of 3 forces (LEP) Solar Neutrino mixing (  - e ) is large SuperKamiokande, SNO, KamLAND Seesaw mechanism Muon (g-2) may be SUSY And more…  e  GUT, m

3. ICEPP, University of Tokyo Y. Hisamatsu, T. Iwamoto, T. Mashimo, S. Mihara, T. Mori, H. Nishiguchi, W. Ootani, K. Ozone, T. Saeki, R. Sawada, S. Yamada, S. Yamashita KEK, Tsukuba T. Haruyama, A. Maki, Y. Makida, A. Yamamoto, K. Yoshimura Osaka University Y. Kuno Waseda University T. Doke, J. Kikuchi, S. Suzuki, K. Terasawa, A. Yamaguchi, T. Yoshimura Budker Institute, Novosibirsk L.M. Barkov, A.A. Grebenuk, D.G. Grigoriev, B, Khazin, N.M. Ryskulov PSI, Villigen J. Egger, P. Kettle, M. Hildebrandt, S. Ritt The MEG Collaboration INFN & Pisa University A. Baldini, C. Bemporad, F.Cei, M.Grassi, F. Morsani, D. Nicolo’, R. Pazzi, F. Raffaelli, F. Sergiampietri, G. Signorelli INFN & Pavia University A.de Bari, P. Cattaneo, G. Cecchet, G. Nardo’, M. Rossella INFN & Genova University S. Dussoni, F. Gatti, D. Pergolesi, R. Valle INFN Roma I D. Zanello INFN & Lecce University S. Spagnolo, C. Chiri, P. Creti, M. Panareo, G. Palama’

4. Spokespersons: T.Mori, A.Baldini Technical Coordinator: S.Ritt Detectors: Beam line:PSIP.-R.Kettle COBRA:KEK/TokyoW.Ootani Drift Chamber:PSIJ.Egger Timing Counter:Genova/Pavia/Roma G. Cecchet Photon Detector:Tokyo/KEK/PisaS.Mihara Trigger:PisaM.Grassi DAQ/Elec.:PSIS.Ritt Offline:S.Yamada/F.Cei/P.Cattaneo The MEG Collaboration

5. The MEG Detector

7. Placed in SLS hall for the initial test. The installation in πE5 is planned this April. COBRA arrived at PSI!

8. Excitation Test at PSI Excitation test was done between Jan.17-27,2004. Full excitation for SC and 8% excitation for NC because of limited utility at SLS. Field mapping study is starting at SLS hall.

9. COBRA Magnet 2002200320042005 Test Milestone AssemblyDesignManufactoring DesignAss.TestWinding & Cryo. Deliv. PSI Test Field Measurement Platform

10. optional wall small rail electronics LXe storage compressor LN 2 line Trigger & DAQ HV triplets separator Transport solenoid Experiment Area Layout 2003: established beam line design

11. Beam 2002200320042005 Test Milestone AssemblyDesignManufactoring Studies Solenoid BTS Triplet I + II Target Part 1 New Separator Part 2 Beam Line Commissioning BTS + COBRA coupling being studied

12. Drift Chamber Final design Know how to build it

13. 2002200320042005 Test Milestone AssemblyDesignManufactoring Full Prototype Medium PrototypeCharge division & Cosmics FP Full Detector (18 DC) Positron Tracker Full Prototype Beam test

14. Timing Counter Minimal Cross Section 39x30 mm 60º PM section PM active diameter 20º 8.5º From COBRA center 105 cm 10º 25 cm B B 0.75 T1.05 T -Final design in progress -APD tests for Phi counters (trigger) -Tests under B field planned

15. Timing Counter Beam Test 2002200320042005 Test Milestone AssemblyDesignManufactoring Design Assembly PMT EvaluationPMT procur. Procur & Manuf. 2” Fine Mesh 19 dyn. R5924 APD EvaluationAPD testAPD procur. 5x5 mm APD Hmamatsu

16. Carbon degrader Lead Collimator at the beam line exit LXe Photon Detector Beam test at PiE1 in Sept-Dec 2003

17. Elementary process  - (essentially) at rest captured on protons:  - p   0 n  - p  n   0    Photon spectru m 54.982.9 129 MeV M  /2  M  /2(1  cos  * ) M  /2 ** E  =55 MeV   * = 

18. Energy measurement FWHM Material, leakage Background rejection

19. ~4.5%

20. FWHM [%] center of the detector center of F14 center of F21 center of F20 center of F15 4.3±1.04.8±0.44.6±0.7 4.5±0.64.5±0.34.5±0.6 4.1±0.95.0±0.55.0±1.6

22. #689[6-7], trigger:S1*Xe

23. Laser-Compton scattering at TERAS 10, 20, 40MeV

24. PSI 2003 TERAS 2003 alpha PSI 2003 TERAS 2003 alpha

25. L-R timing resolution Sigma = 65 psec

26. Resolution improves in proportion to 1/sqrt(Npe). For 52.8 MeV  psec + depth resolution. QE improvement and wave-form analysis will help to achieve better resolution. KSR measurement Of electron beam In 2002

27. Depth (cm) E deposit/unit length electron gamma

28. Xe – TC timing resolution Sigma = 100 psec

29. Position measurement

31. Background and Sensitivity July 2002Now Gamma Energy (%)4.0-4.54.5-5.0* e+ Timing (nsec)0.1*0.1* Gamma Timing0.1<0.23* Gamma Position (mm)9-10.54.5-9.0* Gamma acceptance0.6>0.4* Muon rate (10 8 /sec)0.2-0.30.2-0.3 Running Time (10 7 sec)2.64.0 Accidental Rate (10 -14 )2.2-3.52.3-3.5 # Accidental Events0.60.6 90% CL Limit (10 -13 )1.0-1.61.2-1.7 * Measured More detailed calculation necessary

32. QE abs =1 m abs =  5%6%2.0% 10%6%1.7% 20%6%1.5%

33. Problems arising… - PMT instability - neutron background

34. Photon Detector 2002200320042005 Test Milestone AssemblyDesignManufactoring Large PrototypeBeam Test Vessel DesignAssembly & Test PMT Delivery + Testing RefrigeratorManufactoringAssembly Liq. Purification AssemblyTest Manufactoring Engineering runs

35. Prototype system tests Debugging of the first board Type0 in Pisa –A minor error fixed System assembled at PSI in Nov. ‘ 03 – 100MHz synchronous operation – Negligible transmission error rate – Satisfactory operation of the analog interface Connection with the Large Prototype –PMT from #0 to #31 –Collected data Alpha Led  0 Trigger / DAQ / Electronics

36. The board Type0 PMT inputs LVDS transm. LVDS receiv. FADC FPGA configuration EPROMS Differential drivers package error solved with a patch board control signals.

37. Internal trigger Time [10 ns] Amplitude [mV] Max. Amplitude (  2) Index of Max Amplitude sum Pulse time Input cyclic-buffer board 0 Output cyclic-buffer board 0

38. Full System 2002200320042005 Test Milestone AssemblyDesignManufactoring Prototype Board Final Prototype Trigger now

39. PMC carrier board Joint effort with the MAGIC experiment (Uni. of Siena and INFN Pisa) – Clock control (locking to external source) – DRS readout with FADC – DRS control signals DRS 1 st Prototype Wave form digitizer - DRS

40. DRS (DAQ) 2002200320042005 Test Milestone AssemblyDesignManufactoring 2 nd Prototype Tests1 st Prototype Boards & ChipTest now

41. By May 2004: -Finish merging LXe geometry & scintillation tracking (Cei/Yamada) -ZEBRA framework for MC outputs (Cattaneo) By July 2004: -Detector digitization (TC:Paolo, XE: Yamada/Cei, DC: Nishiguchi) Unified MC available for the DC beam test in summer Offline Software More people are joining the efforts now Coordination meeting planned in May-June

42. Conclusion