COMETμ-e conversion search at J-PARC

μ-e conversion physics• 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

COMET Experiment• Search for LFV process, μ-e

conversion with a sensitivity of 10-

16 beyond the world’s best limit of 7x10-13 obtained by SINDRUM II at PSI

• J-PARC high- intensity proton beam– 8GeV, 7μA

• Innovative apparatus – Pion collection– Muon Transport– Electron Spectrometer

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, 3.4kW in Phase I and 56kW in Phase II

COMET Staging plan• Phase I

– Construct Capture solenoid and transport line down to the 1st 90 degree bend• Detector system (with a

detector solenoid) is connected at the end

– 10-14 sensitivity with 3.4kW proton beam, 3 weeks DAQ

– Funding approval in JFY 2012 supplementary budget

• Phase II– 10-16 sensitivity with 56kW

proton beam (2 years DAQ)

2012 2013 2014 2015 2016 2017

Superconducting solenoidExperiment area

Beamline

Detector

Phase I schedule after JFY2012 budget approval

Phase II preparation will be started in parallel toPhase I DAQ.

cf. mu2e is planning to start DAQ in late 2010’s

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

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

Expected UK contribution

• Software development• Frontend electronics• Trigger and computing• Silicon detector for beam monitoring– experience gained in high-luminosity experiment

(LHCb)• High-power target (RAL)

SC test coil（ collaboration with FNAL）→

↑Neutron irradiation test on the SC wire

←Calorimeter prototype（ GSO).LYSO development in progress in parallel

←Straw tube trackerPrototype

→COMET employs the same technology used in NA62 for straw tracker construction