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(Stopped) Muon Physics : Experimental Overview

(Stopped) Muon Physics : Experimental Overview. Yoshitaka Kuno Osaka University Snowmass 2001 July 6th, 2001. Outline. Introduction Physics Motivation Lepton Flavor Violation (LFV) Current Status of Experiments  e   e  conversion in a muonic atom

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(Stopped) Muon Physics : Experimental Overview

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  1. (Stopped) Muon Physics :Experimental Overview Yoshitaka Kuno Osaka University Snowmass 2001 July 6th, 2001

  2. Outline • Introduction • Physics Motivation • Lepton Flavor Violation (LFV) • Current Status of Experiments • e • econversion in a muonic atom • Muon (g-2), Muon EDM not included (L. Robert, W. Morse talks) • Muon Sources at Front End of Neutrino Factory/Muon Collider • PRISM at JHF, Japan • CERN program • US Programs as NuFACT Front End • How do we fit into the machine staging ? • What are the physics programs, goals (sensitivity) ? Snowmass 2001

  3. Muon Particle Physics Menu • Muon Lepton Flavor Violation • Stopped muon experiments • Muon Moments • Muon (g-2) moments (L. Robert talk) • Muon Edm (W. Morse talk) • Muon in-flight experiments • Muon Lifetime Snowmass 2001

  4. LFV = Lepton Flavor Violation Long history since 1948 (Pontecorvo) Improvement of 2 orders of magnitudes per decade History of LFV Searches Snowmass 2001

  5. Recent Limits of LFV Searches Muon provides most sensitive limits • Large number of muons available • Relatively small mass of muon • Relatively large muon life time Snowmass 2001

  6. |DLi | =1 e eee econversion in a muonic atom |DLi | =2 muonium-antimuonium conversion conversion in a muonic atom Charged Lepton LFV Snowmass 2001

  7. Flavor Physics and LFV normal particles SUSY particles m-e transition diagram squark quark sensitive to slepton mixing ex. K-decays, B-decays slepton lepton(neutrino) ex. neutrino oscillation ex. charged lepton LFV Muon g-2, EDM Snowmass 2001

  8. SUSY-GUT predictions for LFV m  eg m  e conv. t  mg Snowmass 2001

  9. Prediction of SU(5) SUSY-GUT e -e conversion Snowmass 2001

  10. Prediction of SU(5) SUSY-GUT eee  Snowmass 2001

  11. SUSY withRH Majorana Neutrino Related to Neutrino oscillation Snowmass 2001

  12. e Snowmass 2001

  13. Event Signature Ee=E=m/2 (=52.8 MeV) e=180back-to-back) time coincidence Backgrounds prompt physics background e when two neutrinos carry very small energies........ accidental background e+ in e ineor in e+e- annihilation in flight e Signal and Background Snowmass 2001

  14. MEGA at LANL (1985-1995) 8 dwarf chambers for e+ tracking pair spectrometer for  detection a thin slanted target 1.5 T solenoid field B(e)<1.2x10-11 (90% C.L.) M.L.Brook et al., PRL 83 (1999) 1521. 1.5T MEGA for edecay M.L. Brooks PRL 83(1999)1521 BR(e) £ 1.2  10-11 Snowmass 2001

  15. sensitivity = 10-14 e+ spectrometer Constant Bending Radius (COBRA) Liquid Xe g detector Mini-Kamiokande PMT surrounded Duty factor : 100 % Starts in 2004 ? New eat PSI Snowmass 2001

  16. e: Accidental Background Bmeg = 10-14 Nb = 0.5 events • Bmeg = 10-16 • Rm = 1010m/s • Nb ~ 104 events? Snowmass 2001

  17. Y.Kuno and Y.Okada, Physical Review Letters 77 (1996) 434 Y.Kuno, A.Maki and Y.Okada, Physical Review D55 (1997) R2517-R2520 Polarized e Snowmass 2001

  18. Polarized e Snowmass 2001

  19. Accidental Background for Polarized Muons Snowmass 2001

  20. m-e conversion in a muonic atom Snowmass 2001

  21. nucleus m- muon decay in orbit nuclear muon capture m-e conversion in muonic atom • muonic atom (1s state) • neutrinoless muon nuclear capture (= m-e conversion) coherent process lepton flavors changes by one unit. Snowmass 2001

  22. Backgrounds muon decay in orbit(Emax - Ee)5) endpoint comes to the signal radiative muon capture with photon conversion pion capturewith photon conversion cosmic ray Coherent conversion (Z5) Event Signature single mono-energetic electron of Emax = (m-B) MeV m-e conversion: signal and background No accidental background Snowmass 2001

  23. 52 MeV/c m- Reduce muon scattering 50 MHz Reduce pion capture b.g. PMC B(m- Ti  e- Ti) < 6.1  10-13 @1993 run Ti target @1999 Au target @2000 SINDRUM-II at PSI After A. van der Schaaf Snowmass 2001

  24. Aim at B(AleAl-16 5x1011-/spill, 1.1MHz pulse 8GeV proton beam at AGS schedule : 2006 starts See W. Molzon talk tomorrow. MECO (E940) at BNL-AGS Snowmass 2001

  25. Muon Sources at the Front End of Neutrino Factory Snowmass 2001

  26. Staging of NuFACT would give us opportunity to do better experiments. HIPA (high intensity proton accelerator) New Technologies Phase rotation Muon cooling Front End of Neutrino Factory Snowmass 2001

  27. What are advantages at NuFACT Front End ? • Higher Muon Beam Intensity • 1012-1014 muons/sec • 4-6 orders of magnitude from PSI • Narrower Beam Energy Spread • For stopped muon experiments (low energy) • Smaller Beam Emittance • Better Beam Purity • Pion contamination Snowmass 2001

  28. LFV at NuFACT Front End • m-e conversion • Most promising, 10-18 or better • Pulsed beam • eg • Detector resolution / Extended target • continuous beam (to reduce accidentals) • e • Detector resolution / Extended target • continuous beam (to reduce accidentals) Snowmass 2001

  29. Programs after LFV Discovery • Study whether photonic or non-photonic or mixture ? • Compare the other LFV branching ratios • Study the interaction (chirality) ? • Polarized muon LFV • Compare the muon moments • Compare tau LFV SUSY-GUT Snowmass 2001

  30. Study in Japan Snowmass 2001

  31. KEK/JAERI Joint Project Construction have started in FY2001. Snowmass 2001

  32. What is PRISM ? • PRISM (Phase Rotation Intense Slow Muon source) • = a dedicated secondarymuon beam channelwithhigh intensity and • narrow energy spread • for stopped muon experiments. High field Pion Capture Phase Rotation Snowmass 2001

  33. Intensity: 1011-1012/sec At JHF 50 GeV-PS intensity Central kinetic energy = 20 MeV (68 MeV/c) Kinetic energy spread = 0.5-1.0 MeV Beam repetition = 1 kHz See the PRISM talks later. PRISM Snowmass 2001 not in scale

  34. Higher muon intensity 1012m-/sec Pulsed beam (>1 kHz) background rejection Narrow energy spread (±0.5-1.0 MeV) thinner muon-stopping target better e- resolution and acceptance Less scattering background Low momentum muon (=68 MeV/c, or even much less) Less scattering backgrounds Less beam contamination no pion contamination long flight path at FFAG (150 m) Good beam extinction kicker magnet at FFAG entrance No high energy e± PRIME: m-e conversion experiment at PRISM Snowmass 2001

  35. Study at CERN Snowmass 2001

  36. Muon Source at CERN NuFACT After J. Aysto, et al. • SPL (Super Proton Linac)“Physics with Low-energy muons at a Neutrino Factory Complex” Snowmass 2001

  37. CERN Plan at NuFACT • m+ (continuous beam) • Internal target inside the proton accumulator • Quasi-continuous muon beam • m- (bunched beam) • Target at exit of buncher • Pion capture? Or Cloud muon? • Pulse structure? • Pion contamination? • Output from the main muon cooling channel • Pion Free • 200 ± 5 MeV, Snowmass 2001

  38. Study at US (staging) Discuss here at Snowmass ! Snowmass 2001

  39. Machine Staging Scenario • 1. 1-4 MW proton driver • 2. 200 MeV/c intense muon source • 3. 2-3 GeV/c intense muon source • 4. 20-50 GeV/c Neutrino Factory • 5. Muon Collider • 50 GeV, 200 GeV, 1.5 TeV Snowmass 2001

  40. Do we need these ? How can we improve ? Staging Muon Physics Approach Snowmass 2001

  41. What are Our Inputs to Machines ? • Beam Energy • Beam Energy Spread • Beam emittance • Muon polarization Specify Our Physics Programs and Goals ! Snowmass 2001

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