EDM at COSY (JEDI) Selected Issues in Spin Coherence Time

1. EDM at COSY (JEDI)Selected Issues in Spin Coherence Time • Lehrach (FZJ), B. Lorentz (FZJ), • W.Morse (BNL), • N.Nikolaev (FZJ & Landau Inst) • F.Rathmann (FZJ) Workshop on Future PNPI + FZJ (+ Landau Institute) Collaboration PNPI, Gatchina, 15-27 June 2012

2. Layout: • Why the EDM and at which accuracy? • Why, How, When at COSY ? • Momentum spread and retention of precessing horizontal polarization without stable spin axis • RFE(B)-flipper: shall a new element in a ring destroy spin coherence? • Spin Decoherence-free magic energies and flattop RFE flipper • EDM-transparent Wien filter is equivalent to the MDM-transparent RFE flipper (as a side dish if time permits) • In situ systematics with RFB flipper (more from F. Rathmann) • Summary: a stringent bound on the deuteron EDM at COSY is feasible, an opportunity not to miss!

3. Future: Search for Electric Dipole Moments Electric dipole moment (EDM) A permanent EDM of a fundamental particle violates both parity (P) and time reversal symmetry (T). Assuming CPT to hold, the combined symmetry CP is violated as well. Frank Rathmann 19th International Spin Physics Symposium 3

5. EDM at COSY – COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 – 3.7 GeV/c Phase space cooled internal & extracted beams COSY … the spin-physics machine for hadron physics Injector cyclotron f.rathmann@fz-juelich.de Precursor experiments to search for EDMs at COSY 5

6. Importance of Spin Coherence Timefor EDM Searches • Lehrach (FZJ), B. Lorentz (FZJ), • W.Morse (BNL), • N.Nikolaev (FZJ & Landau Inst) • F.Rathmann (FZJ) RWTH / IKP FZJ, 3 May 2012

7. Upper bounds on the neutron EDM

9. Limits for Electric Dipole Moments EDM searches - only upper limits up to now (in ecm): Huge efforts underway to improve limits / find EDMs Sensitivity to NEW PHYSICS beyond the Standard Model

11. Georg Christoph Lichtenberg (1742-1799) “Man muß etwas Neues machen, um etwas Neues zu sehen.” “You have to make (create) something new, if you want to see something new” f.rathmann@fz-juelich.de Precursor experiments to search for EDMs at COSY 11

12. There are two storage ring projects being pursued Copied from R. Talman Copied from A. Lehrach Strong need for a convincing precursor pEDM & dEDM experiment at COSY

13. Future: Search for Electric Dipole Moments NEW: EDM search in time development of spin in a storage ring: “Freeze“ horizontal spin precession; watch for development of a vertical component ! A magic storage ring for protons (electrostatic), deuterons, … One machine with r~30 m Frank Rathmann 19th International Spin Physics Symposium 13

14. Sensitivity of a Dream EDM Experiment P = 0.8 Beam polarization A = 0.6 Analyzing power of polarimeter ER = 17 MV/m Radial electric field strength NBeam = 2·1010 p/fill Total number of stored particles per fill f = 0.55% Useful event rate fraction (polarimeter efficiency) TTot = 107 s Total running time per year Spin = 103 s Polarization lifetime (Spin Coherence Time) for one year measurement Systematic error due to vertical electric fields and horizontal magnetic fields

15. Crucial idea from F.Rathmann: swap the role of the vertical and horizontal polarizations and the constant E-field for RFE-field EDM flipper EDM in the pure radial E-ring: buildup of the vertical polarization from the horizontal one Bill Morse: Solution for COSY as it is is a radial RFE-flipper to convert the vertical polarization to the horizontal one Need to cope with the precession of the horizonal polarization Need very long SCT! d < E-24 e.cm for the deuteron EDM is within the reach of COSY (if free of systematics)

16. polarized beam in ring makes one turn ring A one particle with magnetic moment “spin closed orbit vector” “spin tune” Vertical stable polarization Frank Rathmann 16

18. Horizonal spin after flipper αSy θ Beam

20. Spin coherence We usually don‘t worry about coherence of spins along the rotation axis Polarization not affected! At injection all spin vectors aligned (coherent) After some time, spin vectors get out of phase and fully populate the cone Situation very different, when you deal with  Longitudinal polarization vanishes! In an EDM machine with frozen spin, observation time is limited. At injection all spin vectors aligned After some time, the spin vectors are all out of phase and in the horizontal plane Spin coherence time: 103 s for measurement on 10-29 e·cm level

26. Spin Coherence Timewith RFE Flipper • Possibility to increase spin coherence time by 3 to 5 orders of magnitude • Experiment with polarized COSY beam soon

27. In situ access to systematics? • Swap the radial RFE field for the radial RFH field • The magnetic moment shall do the same job as EDM • Go down to micro- & nano-gauss to establish the sensitivity limit

28. Spin Coherence Measurements at COSY • RF Solenoid: • water-cooled copper coil in a ferrite box • Length 0.6 m • Frequency range 0.4 to 1.2 MHz • Integrated field ∫Brms dl ~ 1 T·mm reference oscillation decoherence time oscillation capture Simple model 5 s 25 s 5 s RF solenoid: on off on Spokesperson: E. Stephenson (IUCF)

29. Summary # 1 It´s all about systematics – stupid! … and money

30. Summary # 2: The deuteron EDM < 1 E-24 e cm is within the reach of COSY supplemented by RFE-flipper (in the single-particle approx.) Similar upper bound is feasible for the proton (if decoherence free energies do exist) An obviously long way from an ideal ring to the real thing plagued by systematics But there is an in situ RFB access to sytematics via the magnetic moment of the deuteron (proton...)

34. Spin Coherence Measurements at COSY • RF Solenoid: • water-cooled copper coil in a ferrite box • Length 0.6 m • Frequency range 0.4 to 1.2 MHz • Integrated field ∫Brms dl ~ 1 T·mm reference oscillation decoherence time oscillation capture Simple model 5 s 25 s 5 s RF solenoid: on off on Spokesperson: E. Stephenson (IUCF)

45. EDM Cooperation International srEDM Network Institutional (MoU) and Personal (Spokespersons …) Cooperation, Coordination srEDMCollaboration (BNL) srEDMCollaboration (FZJ) • Common R & D • RHICEDM-at-COSY • Beam Position Monitors Polarimetry • (…) Spin Coherence Time • Beam Cooling • Spin Tracking (…) Study Group DOE-Proposal Precursor; Ring Design CD0, 1, … HGF Application(s) pEDM Ring at BNL JEDI

46. spin manipulation snakes there is an for every point of the orbit Snakes (non-vertical B field) affect flippers ramping through a resonance reverses 180o spin closed orbit Frank Rathmann 19th International Spin Physics Symposium 46

47. EDM Cooperation International srEDM Network Institutional (MoU) and Personal (Spokespersons …) Cooperation, Coordination srEDMCollaboration (BNL) srEDMCollaboration (FZJ) • Common R & D • RHICEDM-at-COSY • Beam Position Monitors Polarimetry • (…) Spin Coherence Time • Beam Cooling • Spin Tracking (…) Study Group DOE-Proposal Precursor; Ring Design CD0, 1, … HGF Application(s) pEDM Ring at BNL JEDI

48. polarized beam in ring “spin closed orbit vector” makes one turn “spin tune” if ║ resonances ring stable polarization if is simple fraction of periodic perturbing precession kick frequency A one particle with magnetic moment Frank Rathmann 19th International Spin Physics Symposium 48

49. EDM at COSY – COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons p = 0.3 – 3.7 GeV/c Phase space cooled internal & extracted beams COSY … the spin-physics machine for hadron physics Injector cyclotron f.rathmann@fz-juelich.de Precursor experiments to search for EDMs at COSY 49

50. Spin Precession (* rest frame) In a real neutral particle EDM experiment for non-relativistic particles, the spin precession is given by: Ideal vertical B-Fields and horizontal E-Fields EDM signal Systematic error