1. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 1/48 WG4 Summary and Future Plans The muon trio and more B. Lee Roberts Department of Physics Boston University roberts@bu.eduroberts@bu.edu http://physics.bu.edu/roberts.html

2. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 2/48 The Muon Trio: Lepton Flavor Violation Muon MDM (g-2) chiral changing Muon EDM

3. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 3/48 MECO MEG PRIME

4. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 4/48 Today with e + e - based theory: All E821 results were obtained with a “blind” analysis. world average

5. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 5/48 Electric and Magnetic Dipole Moments Transformation properties: An EDM implies both P and T are violated. An EDM at a measureable level would imply non-standard model CP. The baryon/antibaryon asymmetry in the universe, needs new sources of CP.

6. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 6/48 Present EDM Limits ParticlePresent EDM limit (e-cm) SM value (e-cm) n future  exp 10 -24 to 10 -25 *projected

7. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 7/48 General Statements We know that oscillate –neutral lepton flavor violation Expect Charged lepton flavor violation at some level –enhanced if there is new dynamics at the TeV scale in particular if there is SUSY We expect CP in the lepton sector (EDMs as well as oscillations) –possible connection with cosmology (leptogenesis)

8. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 8/48 The Physics Case: Scenario 1 –LHC finds SUSY –MEG sees  → e  The trio will have SUSY enhancements –to understand the nature of the SUSY space we need to get all the information possible to understand the nature of this new theory

9. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 9/48 SUSY predictions of   A  e - A From Barbieri, Hall, Hisano … MECO single event sensitivity 10 -11 10 -13 10 -15 10 -19 10 -17 10 -21 PRIME single event sensitivity   e  &  - A  e - A Branching Ratios are linearly correlated 100 200 300 100 200 300 Complementary measurements (discrimination between SUSY models) ReReReRe

10. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 10/48 Experimental bound Largely favoured and confirmed by Kamland Additional contribution to slepton mixing from V 21, matrix element responsible for solar neutrino deficit. (J. Hisano & N. Nomura, Phys. Rev. D59 (1999) 116005). All solar  experiments combined tan(  ) = 30 tan(  ) = 0 MEG goal AfterKamland Connection with oscillations

11. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 11/48 SUSY connection between a , D μ, μ → e

12. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 12/48 a μ sensitivity to SUSY (large tan  )

13. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 13/48 SUSY, dark matter, (g-2)   CMSSM

14. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 14/48  E969 =  now

15. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 15/48  E969 

16. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 16/48 The Physics Case Scenario 2 –LHC finds Standard Model Higgs at a reasonable mass, nothing else, (g-2) discrepancy could be the only indication beyond neutrino mass of New Physics Then precision measurements come to the forefront, since they are sensitive to heavier virtual particles. –μ-e conversion is especially sensitive to other new physics besides SUSY

17. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 17/48 Sensitivity to Various  e Conversion Mechanisms Compositeness Second Higgs doublet Heavy Z’, Anomalous Z coupling Predictions at 10 -15 Supersymmetry Heavy Neutrinos Leptoquarks After W. Marciano

18. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 18/48  - N  e - N vs.  e  as Probes of LFV  - N  e - N is more sensitive for essentially all processes not mediated by photon  - N  e - N is more sensitive than is  e  to chirality conserving processes  e  is more sensitive for processes mediated by photons – B(  e  )  300  R  e for these processes The motivation is sufficiently strong that both experiments should be done –Relative rates for  e  and  - N  e - N would give information on underlying mechanism –A significant rate for  e  with polarized muons could give additional information on mechanism

19. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 19/48 The Experiments: LFV μe conversion and Muonium-anti-Muonium conversion –pulsed beam μ → e  and eee –DC beam

20. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 20/48 Near Term Experiments on LFV MEG @ PSI (under construction, data begins in 2006) –10 -13 BR sensitivity MECO @BNL (funding not certain) –10 -17 BR sensitivity

21. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 21/48 MEG @ PSI (10 -13 BR sensitivity) Discovery Potential: 4 Events BR = 2 X 10 -13

22. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 22/48 The MECO Apparatus Straw Tracker Crystal Calorimeter Muon Stopping Target Muon Beam Stop Superconducting Production Solenoid (5.0 T – 2.5 T) Superconducting Detector Solenoid (2.0 T – 1.0 T) Superconducting Transport Solenoid (2.5 T – 2.1 T) Collimators 10 -17 BR single event sensitivity p beam approved but not funded

23. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 23/48 PRIME-type experiment –with FFAG muon storage ring –few X 10 -19 Such an experiment is perfect for the front end of a muon factory Future Experiments on LFV

24. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 24/48

25. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 25/48  + e - →  - e + Muonium productionFull M search

26. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 26/48 An improvement of 10 2 on G MM would confront these types of models which would also contribute to double  – decay. At the front end of a factory with a pulsed beam this might be possible.

27. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 27/48 Future Muon (g-2) Experiments E969 @ BNL 0.5 → 0.20 ppm (scientific approval but not funded) –expected near-term improvement in theory, → the ability to confront the SM by ~ x 2 The next generation 0.20 → 0.06 ppm –substantial R&D would be necessary new ring or improved present ring?

28. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 28/48 Use an E field for vertical focusing spin difference frequency =  s -  c 0

29. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 29/48 Muon (g-2): Store  ± in a storage ring magnetic field averaged over azumuth in the storage ring

30. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 30/48 E969: Systematic Error Goal Field improvements will involve better trolley calibrations, better tracking of the field with time, temperature stability of room, improvements in the hardware Precession improvements will involve new scraping scheme, lower thresholds, more complete digitization periods, better energy calibration Systematic uncertainty (ppm)1998199920002001E969 Goal Magnetic field –  p 0.50.40.240.170.1 Anomalous precession –  a 0.80.3 0.210.1

31. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 31/48 SM value dominated by hadronic issues: Lowest order hadronic contribution ( ~ 60 ppm) Hadronic light-by-light contribution ( ~ 1 ppm) The error on these two contributions will ultimately limit the interpretation of a more precise muon (g-2) measurement.

32. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 32/48 A (g-2) experiment to ~0.06 ppm? Makes sense if the theory can be improved to 0.1 ppm, which is hard, but maybe not impossible. With the present storage ring, we already have

33. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 33/48 Where we came from:

34. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 34/48 Today with e + e - based theory: All E821 results were obtained with a “blind” analysis. world average

35. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 35/48 Muon EDM Present limit ~10 -19 e-cm Could reach 10 -24 to 10 -25 at a high intensity muon source?

36. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 36/48 Spin Precession Frequencies:  in B field with both an MDM and EDM The EDM causes the spin to precess out of plane. The motional E - field, β X B, is much stronger than laboratory electric fields. ~GV/m with no sparks!

37. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 37/48 EDM – up/down Asymmetry avoid the magic γ and use a radial E-field to turn off (g-2) precession Place detectors above and below the vacuum chamber and look for an up/down asymmetry which builds up with time

38. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 38/48 Up/Down asymmetry vs. time time

39. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 39/48 The EDM ring run with both μ + and μ -. there must be regions of combined E+B along with separate focusing elements. There needs to be a scheme to inject CW and CCW. EBp  R 2 MV/m 0.25T0.5 GeV/c 511μs7 m Possible Muon EDM Ring Parameters

40. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 40/48 A possible lattice Yuri Orlov

41. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 41/48 NP 2 the figure of merit is N μ times the polarization. we need to reach the 10 -24 e-cm level. Narrow pulsed beam every ~100  s

42. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 42/48 Additional topics: Muons for condensed matter (  SR) Muon catalyzed fusion (  CF) Muon lifetime (G F ) Muon capture (g p )...

43. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 43/48 B(z) z 0 Superconductor  Magnetic field profile B(z) over nm scale  Characteristic lengths of the sc  Depth dependent  SR measurements in near surface regions  B(z)

44. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 44/48 Magnetic Field Profile in YBa 2 Cu 3 O 7-   0  90 local response  exponential profile  Direct test of theories (London, BCS)  Direct, absolute measurement of magnetic penetration depth  effective mass  density of supercarriers T.J. Jackson, T.M. Riseman, E.M. Forgan, H. Glückler, T. Prokscha, E. Morenzoni, M. Pleines, Ch. Niedermayer, G. Schatz, H. Luetkens, and J. Litterst, Phys. Rev. Lett. 84, 4958 (2000).

45. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 45/48 Beams needed: Pulsed intense muon beams –energy from surface (28 MeV/c) to 3.1 Gev/c A few experiments could used DC beam, but almost all can use the pulse structure of a pulse, and some  s with no beam

46. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 46/48 Beam requirements: A few examples Exp. ## p pulse width T off pp  p  /p  Pol →e→e 10 20 <20 ns 1–100  s ≤28 Mev/c 3%N (g-2) 10 15 <20 ns1 ms3.1 Gev/c 0.5%Y  EDM 10 18 <20 ns 100-500  s 0.3-1.5 Gev/c ~0.1%Y

47. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 47/48 Plans for next year LFV experiments will continue to develop the techniques needed for these challenging experiments Muon EDM collaboration will continue to investigate the appropriate ring structure. Participate in scoping study for factory –At present muon physics is not mentioned in the document of 10 June 2005

48. WG4:  physics B. Lee Roberts, on behalf of the Intense Muon Physics Working Group - p. 48/48 Summary The questions addressed are at the center of the field of particle physics There is an important program of muon physics which will be possible at the front- end of a factory. –It makes use of the very intense flux which will be available there If such a muon facility exists, there will also be a program of other very interesting muon experiments which is possible.