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

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

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

/15 March 2nd, Summary of LFV experiments  → e   → eA  → eee SUSY SU(5) BR(   e  ) =   A  eA =  BR(     ) = SUSY SU(5) BR(   e  ) =   A  eA =  BR(     ) = Current Limits: BR(  +  e +  ) < 1.2 x (MEGA) 1)  Ti → eTi < 7 x (SINDRUM II) 2) Current Limits: BR(  +  e +  ) < 1.2 x (MEGA) 1)  Ti → eTi < 7 x (SINDRUM II) 2) 1) hep-ex/ ) A. van der Schaaf, priv. comm. BR Year MEG “Supersymmetric parameterspace accessible by LHC” W. Buchmueller, DESY, priv. comm.

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

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

/15 March 2nd, 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

/15 March 2nd, 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

/15 March 2nd, 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

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

/15 March 2nd, Drift chamber for positrons

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

/15 March 2nd, Pile-up rejection with the DRS chip 4 GHz sampling 12 bits 32 channels on VME board ~ 100 € per channel Licensed to CAEN, Italy 4 GHz sampling 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

/15 March 2nd, Current sensitivity estimation Subject to future improvements

March 2nd, Plans Data taking from 2007 on to reach sensitivity (90% CL) Obtain a “significant” result before the LHC era Eventual reach during LHC era Plans Data taking from 2007 on to reach sensitivity (90% CL) Obtain a “significant” result before the LHC era Eventual reach during LHC era R&D Engineering Data