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Muon - Electron Conversion at J-PARC COMET-PRISM/PRIME

Muon - Electron Conversion at J-PARC COMET-PRISM/PRIME. Ed Hungerford University of Houston for the COMET Collaboration. The COMET-PRISM Collaboration. Department of Physics, Brookhaven National Laboratory, USA R. Palmer Y. Cui

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Muon - Electron Conversion at J-PARC COMET-PRISM/PRIME

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  1. Muon - Electron Conversion at J-PARCCOMET-PRISM/PRIME Ed Hungerford University of Houston for the COMET Collaboration Ed Hungerford for the COMET collaboration

  2. The COMET-PRISM Collaboration Department of Physics, Brookhaven National Laboratory, USA R. Palmer Y. Cui Department of Physics, University of Houston, USA E. Hungerford K. Lau Department of physics and astronomy, University of British Columbia, Vancouver, Canada D. Bryman TRIUMF, Canada T. Numao Imperial College London, UK A. Kurup, J. Pasternak, Y. Uchida, P. Dauncey, U. Egede, P. Dornan, and L. Jenner University College London, UK M. Wing, M. Lancaster, and R. D’Arcy* Institute for Chemical Research, Kyoto University, Kyoto, JapanY. Iwashita, Department of Physics, Osaka University, Japan M. Aoki, Md.I. Hossain, T. Itahashi, Y. Kuno, N. Nakadozono*, A. Sato, T. Tachimoto* and M. Yoshida Department of Physics, Saitama University, Japan M. Koike and J. Sato Department of Physics, Tohoku University, Japan Y. Takubo, High Energy Accelerator Research Organization (KEK), JapanY. Arimoto, Y. Igarashi, S. Ishimoto, S. Mihara, H. Nishiguchi, T. Ogitsu, M. Tomizawa, A. Yamamoto, and K. Yoshimura Institute for Cosmic Ray Research, Japan M. Yamanaka 43 people from 13 institutes ( 25th May 2009 ) JINR, Dubna, Russia V. Kalinnikov, A. Moiseenko, D. Mzhavia, J. Pontecorvo, B. Sabirov, Z. Tsamaiaidze, and P. Evtukhouvich Ed Hungerford for the COMET collaboration 2

  3. Muon-to-Electron (μ-e) Conversion Lepton Flavor Violation Lepton Flavor Changes by one unit Coherent Conversion μ- + A →e-+ A Muonic Atom μ Decay in Orbit (DIO) μ- → e-νν Nuclear Capture μ- + A →ν+ [N +(A-1)] Ed Hungerford for the COMET collaboration

  4. IntroductiontoCOMET-PRISM/PRIME COMET (Phase I)PRISIM/PRIME (Phase II) is a search for coherent, neutrino-less conversion of muons to electron (μ-e conversion) at a single sensitivity of 0f 0.5x10-1610-18 The experiment offers a powerful probe for new physics beyond the Standard Model. It will be undertaken at J-PARC. Phase I (COMET) uses a slow-extracted, bunched 8 GeV proton beam from the J-PARC main ring. A proposal was submit to J-PARC Dec. 2007, and a Conceptual Design Report submitted June 2009. COMET now has Stage-1 approval from the J-PARC PAC (July 2009). The Collaboration is completing R&D for a TDR. Ed Hungerford for the COMET collaboration

  5. The SINDRUM-II Experiment (at PSI) Published Results SINDRUM DIO Signal at `muon mass COMET Al Target SINDRUM-II used a continuous muon beam from the PSI cyclotron. To eliminate beam related background from the beam, a beam-veto counter was used. This technology cannot be used with higher beam rates in modern beamlines. DIO 5/30/09 Ed Hungerford for the COMET collaboration 5

  6. Sensitivities SUSY-Seesaw Model ( SUSY-GUT SO(10) ) • Masieroet al., J. High Energy Phys. • JHEP03, (2004) 046. Present Sindrum Limit B(μ→ e + g)10-13 COMET B(μ + Al → e + Al) < 10-16 PRISM Ed Hungerford for the COMET collaboration

  7. Prediction from SUSY-SU(5) Tan(  ) = ( h2/ h1) ;  = higgsino mass J. Hisano, T. Moroi, K. Tobe and M. Yamaguchi, Phys. Lett. B391, 341 (1997) Ed Hungerford for the COMET collaboration

  8. Design Considerations for COMET (and generally all) μ to e Experiments • Electron Resolution Minimal Detector Material – Thin, Low Z Vacuum Environment REDUNDENT measurements of the electron track • Rates Up to 500 kHZ single rates Large channel count R/O timing (~1-2ns) and analog information • Dynamic Range Protons 30-40 times Eloss for MIP Pileup and saturation Maintain MIP track efficiency • Low-Power, Low-foot print electronics Heat Signal Transmission, inside-to -outside the vacuum Noise • REDUNDANCY Redundancy (Redundancy, Redundancy, Redundancy) Ambiguous hits, dead channels, accidentals Reconstruction of ghost tracks • Robust measurements Ed Hungerford for the COMET collaboration

  9. PRISM COMET COMET  PRISM at J-PARC • Needs a muon storage ring. • Requires a fast-extracted, pulsed-beam. • Requires a new beamline and hall. • Experience and components of Phase I • Extends the reach by 100 • Modification of MECO/MELC • Requires a slow-extracted, pulsed -beam • Proposed for the J-PARC NP Hall. • Regarded as phase I - Early realization Early Realization Phase II Ed Hungerford for the COMET collaboration

  10. J-PARCJapan Proton Accelerator Research Complex Hadron Beam Facility NP-Hall 500 m Linac (330m) Neutrino to Kamiokande 3 GeV Rapid-Cycling Synchrotron, RCS (25 Hz, 1MW） 50 GeV Main Ring Synchrotron (0.75 MW) PRISM-Phase1 PRISM-Phase2 Ed Hungerford for the COMET collaboration

  11. μ→eγ and μ-e Conversion μ→eγ : Accidental background is given by (rate)2. To push sensitivity the detector resolutions and timing must be improved. However, (in particular for the photon) it would be hard to better MEG with present technology. The ultimate sensitivity is about 10-14 (with a run of 108/sec). μ-e conversion: Improvement of a muon beam is possible, both in purity (no pions) and in intensity (thanks to muon collider R&D). A higher beam intensity can be used with present timing because no coincidence is required. 5/30/09 Ed Hungerford for the COMET collaboration 11

  12. Overview of COMET • Proton Beam • The Muon Source • Proton Target • Pion Capture • Muon Transport • The Detector • Muon Stopping Target • Electron Transport • Electron Detection Ed Hungerford for the COMET collaboration

  13. Comparison to MECO Proton Target tungsten (MECO) graphite (J-PARC) Muon Transport Magnetic field distributions are different. Efficiency of the muon transport is almost the same. Spectrometer For 1011 stopping muons/sec Straight Solenoid (MECO) ~500 kHz/wire Curved Solenoid (J-PARC) ~ 300 DIO Hz /detector Detector Wire Planes rather than straws MECO COMET Ed Hungerford for the COMET collaboration

  14. Target and Detector Solenoids a muon stopping target, curved solenoid,tracking chambers, and a calorimeter/trigger and cosmic-ray shields. Ed Hungerford for the COMET collaboration

  15. Background Rejection (preliminary) Ed Hungerford for the COMET collaboration

  16. Signal Sensitivity Single event sensitivity Nμ is a number of stopping muons in the muon stopping target which is 6x1017 muons. fcap is a fraction of muon capture, which is 0.6 for aluminum. Ae is the detector acceptance, which is 0.07. Ed Hungerford for the COMET collaboration

  17. Summary COMET is a Phase I search for coherent, neutrino-less conversion of muons to electron (μ-e conversion) at a single event sensitivity of 10-16 The experiment offers a powerful probe for new physics beyond the Standard Model. The experiment will be undertaken at the J-PARC NP Hall using a slowly-extracted, bunched proton beam from the J-PARC main ring. More Advanced design, attempting to reduce backgrounds and miss-constructed electron trajectories The Experiment is developing a TDR and refining design details. The experiment has completed a CDR and has Stage-1 approval of the J-PARC PAC. As a follow-on to COMET, PRISM/PRIME (Phase II) would reach a sensitivity of 10-18. It requires a new beam line, new hall, and a muon storage ring Ed Hungerford for the COMET collaboration

  18. Supplementary Slides

  19. Backgrounds Background rejection is crucial in single-event/few–event searches Avoids statistical separation of events from background Conspiring events can mimic a signal It’s always the background that you don’t predict which imposes the limits - (Redundancy, Redundancy, Redundancy, ) Ed Hungerford for the COMET collaboration

  20. The MELC/MECO Proposals The MECO Experiment at BNL • MELC (Russia) • MECO (BNL) • To eliminate beam related • background, beam • pulsing was adopted • (with delayed • measurement). • To increase number of • muons pion capture • in a high-field • solenoidal . • Curved solenoid used for • momentum pre- • selection Cancelled in 2005 Ed Hungerford for the COMET collaboration

  21. Pion Capture Solenoid • A large muon yield can be achieved by a large solid angle, pion-capture, high- field solenoid surrounding the proton target. • B=5T,R=0.2m, PT=150MeV/c. • Superconducting Solenoid Magnet for pion capture • 15 cm radius bore • a 5 tesla solenoidal field • 30 cm thick tungsten radiation shield • heat load from radiation • a large stored energy Ed Hungerford for the COMET collaboration

  22. Electron Detection (preliminary) • Wire Plane Trackers for electron momentum • Vacuum in constant 1T magnetic field. • Straw tube 25μm walls, 5 mm diameter. • One plane has 4 views (x ,y) + (x’,y’) • Five planes are placed 48 cm apart • 250μm position resolution. • σ = 230 keV/c (multiple scattering dominated.) • Electron calorimeter • Triggers R/O • Redundant Energy Measurement • Candidates are GSO or LSO(LYSO). • APD readout . 16 Wire Units 5 mm Wire spacing 208 wires/array 832 wires/plane 4160 wires/detector Wire Plane Tracker ~1.2m Ed Hungerford for the COMET collaboration Trigger Calorimeter

  23. Cosmic Ray Shields Both passive and active shields are used. Passive shields 2 meter of concrete and 0.5 m of steel Active shields layers of scintillator veto counters (~1% inefficiency) Ed Hungerford for the COMET collaboration

  24. Schematic of System Readout Plane Readout Control Off-line Database FE ASIC Analog Buffer ADC Local Readout Control (in CPLD) FE ASIC Section Readout Control (FPGA) W Section Each plane will have its own data link to send data from the detector. In each plane, the readout sequence is organized in sections. Each section is controlled by a FPGA. Locally, there is a CPLD to control the A-to-D conversion.

  25. Muon Transport Solenoids Muons are transported from the capture section to the detector by the muon transport beamline. Requirements : long enough for pions to decay to muons (> 20 meters ≈ 2x10-3). high transport efficiency negative charge selection low momentum cut (Pμ>75 MeV/c) Straight + curved solenoid transport system to select momentum and charge Ed Hungerford for the COMET collaboration

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