1. Status of the MEG Experiment  → e  On behalf of the MEG collaboration Stefan Ritt Paul Scherrer Institute, Switzerland

2. /15 March 2nd, 20062 LVF in the charged sector d t b 1 2 3 Generation Quarks Leptons   e c u s e   Energy Quark mixing (CKM) Neutrino Oscillations Mixing in the charged Lepton sector?

3. /15 March 2nd, 20063 LFV in the SM vs. SUSY SM SUSY probes slepton mixing matrix ≈ 10 -12 LFV in the SM is immeasurable small SUSY models predicts BR(  → e  ) just below the current experimental limit of 1.2 x 10 -11 Decay  → e  is free of “SM background” (no hadronic corrections) LFV in the SM is immeasurable small SUSY models predicts BR(  → e  ) just below the current experimental limit of 1.2 x 10 -11 Decay  → e  is free of “SM background” (no hadronic corrections) The discovery of  → e  would by physics beyond the SM

4. /15 March 2nd, 20064 Summary of LFV experiments 1940 1950 1960 1970 1980 1990 2000 2010 10 -1 10 -2 10 -3 10 -4 10 -5 10 -6 10 -7 10 -6 10 -9 10 -10 10 -11 10 -12 10 -13 10 -14 10 -15  → e   → eA  → eee SUSY SU(5) BR(   e  ) = 10 -13   A  eA = 10 -15  BR(     ) = 10 -8 SUSY SU(5) BR(   e  ) = 10 -13   A  eA = 10 -15  BR(     ) = 10 -8 Current Limits: BR(  +  e +  ) < 1.2 x 10 -11 (MEGA) 1)  Ti → eTi < 7 x 10 -13 (SINDRUM II) 2) Current Limits: BR(  +  e +  ) < 1.2 x 10 -11 (MEGA) 1)  Ti → eTi < 7 x 10 -13 (SINDRUM II) 2) 1) hep-ex/9905013 2) A. van der Schaaf, priv. comm. BR Year MEG “Supersymmetric parameterspace accessible by LHC” W. Buchmueller, DESY, priv. comm.

5. /15 March 2nd, 20065  – e Conversion: Sindrum II @ PSI  - Ti  e - Ti : 4.3 x 10 -12 (90% C.L.)  - Au → e - Au : <7 x 10 -13 (90% C.L.)  - Ti  e - Ti : 4.3 x 10 -12 (90% C.L.)  - Au → e - Au : <7 x 10 -13 (90% C.L.) B  e =4 10 -12 Limited by  decay in flight

6. /15 March 2nd, 20066  – e Conversion: Future  – e Conversion down to 10 -17 RSVP program at BNL Terminated in August 2005 PRISM/PRIME at J-PARC  – e Conversion down to 10 -18 10 11 – 10 12  /sec pulsed beam  /  < 10 -18 Magnet construction -2008

7. /15 March 2nd, 20067 Univ. of Tokyo Y. Hisamatsu, T. Iwamoto, T. Mashimo, S. Mihara, T. Mori, Y. Morita, H. Natori, H. Nishiguchi, Y. Nishimura, W. Ootani, K. Ozone, R. Sawada, Y. Uchiyama, S. Yamashita KEK T. Haruyama, K. Kasami, A. Maki, Y. Makida, A. Yamamoto, K. Yoshimura Waseda Univ. K. Deguchi, T. Doke, J. Kikuchi, S. Suzuki, K. Terasawa INFN Pisa A. Baldini, C. Bemporad, F. Cei, L.del Frate, L. Galli, G. Gallucci, M. Grassi, F. Morsani, D. Nicolò, A. Papa, R. Pazzi, F. Raffaelli, F. Sergiampietri, G. Signorelli INFN and Univ. of Genova S. Cuneo, D. Bondi, S. Dussoni, F. Gatti, S. Minutoli, P. Musico, P. Ottonello, R. Valle INFN and Univ. of Pavia O.Barnaba, G. Boca, P. W. Cattaneo, G. Cecchet, A. De Bari, P. Liguori, G. Musitelli, R. Nardò, M. Rossella, A.Vicini INFN and Univ. of Roma I A. Barchiesi, D. Zanello INFN and Univ. of Lecce M. Panareo Paul Scherrer Institute J. Egger, M. Hildebrandt, P.-R. Kettle, S. Ritt, M. Schneebeli BINP Novosibirsk L. M. Barkov, A. A. Grebenuk, D. N. Grigoriev, B. I. Khazin, N. M. Ryskulov JINR Dubna A. Korenchenko, N. Kravchuk, A. Moiseenko, D. Mzavia Univ. of California, Irvine W. Molzon, M. Hebert, P. Huwe, J. Perry, V. Tumakov, F. Xiao, S. Yamada MEG  ~40 FTEs

8. /15 March 2nd, 20068 Decay topology e     e  180º  → e  signal very clean E g = E e = 52.8 MeV   e = 180º e and  in time e    e  e    e  Annihilation in flight Main background Good energy resolution Good spatial resolution Excellent timing resolution Good pile-up rejection

9. /15 March 2nd, 20069 The MEG Detector 10 7 – 10 8  /sec, 100% duty factor LXe for efficient  detection Solenoidal magnetic spectrometer 10 7 – 10 8  /sec, 100% duty factor LXe for efficient  detection Solenoidal magnetic spectrometer

10. /15 March 2nd, 200610 Detector parts LXe calorimeter prototype“COBRA” solenoid Timing counter

11. /15 March 2nd, 200611 Drift chamber for positrons

12. /15 March 2nd, 200612 Experimental set-up Detailed studies to minimize background from annihilation in flight  E5 beamline  Currently the highest intensity  beam: 10 8  /sec.

13. /15 March 2nd, 200613 Pile-up rejection with the DRS chip 4 GHz sampling rate @ 12 bits 32 channels on VME board ~ 100 € per channel Licensed to CAEN, Italy 4 GHz sampling rate @ 12 bits 32 channels on VME board ~ 100 € per channel Licensed to CAEN, Italy 11 MeV  + 42 MeV   T=15ns Only use waveform Digitizing for the whole experiment ~3000 channels (no ADC, TDC, …) Only use waveform Digitizing for the whole experiment ~3000 channels (no ADC, TDC, …)  shower  source

14. /15 March 2nd, 200614 Current sensitivity estimation Subject to future improvements http://meg.web.psi.ch/docs/calculator/

15. March 2nd, 200615 Plans Data taking from 2007 on to reach 10 -13 sensitivity (90% CL) Obtain a “significant” result before the LHC era Eventual reach 10 -14 during LHC era Plans Data taking from 2007 on to reach 10 -13 sensitivity (90% CL) Obtain a “significant” result before the LHC era Eventual reach 10 -14 during LHC era R&D 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 Engineering Data