1. μ→e search using pulsed muon beam μ -  e - νν nuclear muon capture Muon Decay In Orbit  π - +(A,Z)→(A,Z-1)*, (A,Z-1)* →γ+(A,Z-1), γ→e + e - Prompt timing Other sources μ - decay-in-flight, e - scattering, neutron streaming proton pulse prompt background muon decay SINDRUM II BR[μ - + Au →e - + Au] < 7 × 10 -13 R ext = number of proton between pulses number of proton in a pulse μ-e conversion E μe (Al) ~ m μ -B μ =105MeV – B μ : binding energy of the 1s muonic atom μ - + (A,Z)  ν μ + (A,Z-1) μ - + (A,Z)  e - + (A,Z)

2. Muon Beam Pion/muon collection using gradient magnetic field BlBl Strong Magnetic field in high radiation environment Aluminum stabilized SC Collaborative R&D between COMET & Mu2e Muon transport with large momentum acceptance and momentum selection Mu2eCOMET

3. J-PARC pulsed proton beam to produce pulsed muon beam – 8GeV, 3kW-56kW – Beam extinction factor study 30GeV w/o extraction, R ext < 1.5x10 -11 32m long chain of SC solenoid magnets – pion collection (PS) – muon transport (TS) – muon focusing on the stopping target (ST) – electron momentum selection (SS) – electron spectrometer (DS) Electron spectrometer – 1T solenoidal field, Multi-layer straw tube tracker, crystal calorimeter COMET at J-PARC PS TS ST SS DS

4. COMET Phase I & II Phase I Phase II Phase I – Beam background study and achieving an intermediate sensitivity of <10 -14 – 8GeV, ~3.2kW, ~3 weeks of DAQ Phase II – 8GeV, ~56 kW, 1 year DAQ to achieve the COMET final goal of < 10 -16 sensitivity μ-μ- μ+μ+ 104MeV/c Phase I 0.03 BG expected in 1.5x10 6 sec running time Phase I 2013-2015 Facility construction 2013-2016 Magnet construction & installation 2016 Eng. run & Physics run Phase II Eng. run in 2020(?)

5. 5 COMET Beam Line High-p and COMET beamline construction – Share the upstream Branch from A-line using a Lambertson magnet – COMET branch from high-p line No simultaneous usage of two beam lines  Dipole magnet COMET needs 8GeV proton beam – 3.2kW in Phase I – 56kW in Phase II

6. 6 COMET Experiment Hall Building construction in 2013-2014 High-p beam line installation in 2014 followed by COMET beam line installation Detector installation is started when the building construction completes

7. Phase I Sensitivity and BG 8GeV, 3.2kW proton beam – 2.5x10 12 proton/sec 18 days (1.5x10 6 sec) running time Single event sensitivity – B(μ - +Al→e - +Al) = 3.1x10 -15 Upper limit at 90% C.L. – B(μ - +Al→e - +Al) < 7x10 -15 supposing beam extinction factor of 10 -9SelectionValueComments Geometrical Acc0.24tracking eff. included momentum0.74104.1 < p e < 106 MeV/c Timing0.39same as COMET Trigger and DAQ0.9same as COMET Total0.06 one signal event assuming B(μ-e)=3x10 -15 0.05 BG events 7

8. 8 COMET Staging plan Phase I – Construct Capture solenoid and transport line down to the 1 st 90 degree bend Detector system (with a detector solenoid) is connected at the end – 10 -14 sensitivity with 3.2kW proton beam, 3 weeks DAQ – Funding approval in JFY 2012 supplementary budget Phase II – 10 -16 sensitivity with 56kW proton beam (2 years DAQ) 201220132014201520162017 Superconduct ing solenoid Experiment area Beamline Detector Phase I schedule after JFY2012 budget approval Phase II preparation will be started in parallel to Phase I DAQ. cf. mu2e is planning to start DAQ in late 2010 ’ s Eng. run

9. 9 COMET Phase-I Detector Transverse tracker + calorimeter – Same technology used in Phase II detector – Beam background study – Physics run smaller acceptance than the CDC design CDC + triggering counter – Physics run Detector R&D and simulation work in progress

10. SUSY-GUT, SUSY-seesaw (Gauge Mediated process) – BR = 10 -14 = BR(μ→eγ) × O(α) – τ→lγ SUSY-seesaw (Higgs Mediated process) – BR = 10 -12 ~10 -15 – τ→lη Doubly Charged Higgs Boson (LRS etc.) – Logarithmic enhancement in a loop diagram for μ - N → e - N, not for μ→e γ M. Raidal and A. Santamaria, PLB 421 (1998) 250 and many others SUSY-GUT, SUSY-seesaw (Gauge Mediated process) – BR = 10 -14 = BR(μ→eγ) × O(α) – τ→lγ SUSY-seesaw (Higgs Mediated process) – BR = 10 -12 ~10 -15 – τ→lη Doubly Charged Higgs Boson (LRS etc.) – Logarithmic enhancement in a loop diagram for μ - N → e - N, not for μ→e γ M. Raidal and A. Santamaria, PLB 421 (1998) 250 and many others Theory Models Andre de Gouvea, W. Molzon, Project-X WS (2008) MEG 2013 5.4x10 -13 10