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

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!

Assuming CPT to hold, the combined symmetry CP is violated as well.
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 3 3

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 Precursor experiments to search for EDMs at COSY 5 5

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

Upper bounds on the neutron EDM

Limits for Electric Dipole Moments
EDM searches - only upper limits up to now (in ecm): Particle/Atom Current EDM Limit Future Goal  dn equivalent Neutron  3 10-26 10-28 10-28 199Hg  3.1 10-29 10-29 10-26 129Xe  6 10-27 10-30 – 10-33 10-26 – 10-29 Proton  7.9 10-25 10-29 Deuteron ? 3 10-29 – 5 10-33 Kern EDMs können viel größer sein(thoeretische Vorhersage) Huge efforts underway to improve limits / find EDMs Sensitivity to NEW PHYSICS beyond the Standard Model 9 9

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” Precursor experiments to search for EDMs at COSY 11

Strong need for a convincing precursor pEDM & dEDM experiment at COSY
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 12

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, … particle p (GeV/c) E (MV/m) B (T) proton 0.701 16.789 0.000 deuteron 1.000 -3.983 0.160 3He 1.285 17.158 -0.051 One machine with r~30 m Frank Rathmann 19th International Spin Physics Symposium 13 13 13

Sensitivity of a Dream EDM Experiment
P = Beam polarization A = 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 Yannis Semertzidis, BNL 14 14

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)

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

Horizonal spin after flipper
αSy θ Beam

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  At injection all spin vectors aligned After some time, the spin vectors are all out of phase and in the horizontal plane Longitudinal polarization vanishes! In an EDM machine with frozen spin, observation time is limited. Spin coherence time: 103 s for measurement on e·cm level

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

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

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 Spin coherence time depends on dp/p (much better for cooled beams) Sextupole correction of non-linear fields (done next beam time in week 10-19) Is there a difference between spin coherence time w/o RF flipper 5 s 25 s RF solenoid: on off on Spokesperson: E. Stephenson (IUCF) 28

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

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...)

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 Spin coherence time depends on dp/p (much better for cooled beams) Sextupole correction of non-linear fields (done next beam time in week 10-19) Is there a difference between spin coherence time w/o RF flipper 5 s 25 s RF solenoid: on off on Spokesperson: E. Stephenson (IUCF) 34

International srEDM Network
EDM Cooperation International srEDM Network Institutional (MoU) and Personal (Spokespersons …) Cooperation, Coordination srEDM Collaboration (BNL) srEDM Collaboration (FZJ) Common R & D RHIC EDM-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 45

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

EDM Cooperation International srEDM Network Institutional (MoU) and Personal (Spokespersons …) Cooperation, Coordination srEDM Collaboration (BNL) srEDM Collaboration (FZJ) Common R & D RHIC EDM-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 47

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

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 Precursor experiments to search for EDMs at COSY 49 49

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 JT-1 = Am2 Ecm=Cm=Asm E=1.6*10^-19 50

Assuming CPT to hold, the combined symmetry CP is violated as well.
Search for Electric Dipole Moments Mystery of matter-antimatter asymmetry 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. Precursor experiments to search for EDMs at COSY 51 51 51

Mystery of matter-antimatter asymmetry EDM searches - only upper limits up to now: Huge efforts under way to improve limits / find EDMs Sensitivity to NEW PHYSICS beyond the Standard Model 485. WE-Heraeus-Seminar (July 0406, 2011) Search for Electric Dipole Moments (EDMs) at Storage Rings Precursor experiments to search for EDMs at COSY 52 52 52

Mystery of matter-antimatter asymmetry 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, … particle p (GeV/c) E (MV/m) B (T) proton 0.701 16.789 0.000 deuteron 1.000 -3.983 0.160 3He 1.285 17.158 -0.051 One machine with r ~ 30 m Precursor experiments to search for EDMs at COSY 53 53 53

Precursor experiments to search for EDMs at COSY
An all-in-one machine: Protons E-field only Precursor experiments to search for EDMs at COSY 54

An all-in-one machine: Deuterons E and B fields Precursor experiments to search for EDMs at COSY 55

Spin Dynamics for EDM at COSY
Lehrach (FZJ), B. Lorentz (FZJ, W.Morse (BNL), N.Nikolaev (FZJ & Landau Inst) F.Rathmann (FZJ) PNPI Winter School, Rajvola,

Mystery of matter-antimatter asymmetry 2 beams simultaneously rotating in a ring (CW, CCW) Approved BNL-Proposal: Goal for protons Circumference ~ 200 m Technological challenges ! Spin coherence time (1000 s) Beam positioning (10 nm) Continuous polarimetry (< 1ppm) E - field gradients (~ 17MV/m at 2 cm) Carry out proof of principle experiments (demonstrators) at COSY Precursor experiments to search for EDMs at COSY 57 57 57

COSY: Concept for Snake Should allow for flexible use at two locations Fast ramping (< 30s) Cryogen-free system Should be available in 2012 PAX ANKE ANKE PAX Bdl (Tm) pn→{pp}sπ- at 353 MeV 3.329 PAX at COSY 140 MeV 1.994 PAX at AD 500 MeV 4.090 Tmax at COSY 2.88 GeV 13.887 Precursor experiments to search for EDMs at COSY 58

An all-in-one machine: Helions E and B fields Precursor experiments to search for EDMs at COSY 59

Siberian snake turns spin closed orbit along longitudinal axis
PE 1: Use a combination of a snake and RF fields Snake Snake only Siberian snake turns spin closed orbit along longitudinal axis Precursor experiments to search for EDMs at COSY 60

Snake + RF E-field, odd turns
PE 1: Use a combination of a snake and RF fields RF E-field Snake RF E-field Snake + RF E-field, odd turns Precursor experiments to search for EDMs at COSY 61

Snake + RF E-field, even turns
PE 1: Use a combination of a snake and RF fields Snake + RF E-field, even turns RF E-field Snake RF E-field 2 Snake + reversed RF E-fields  depolarization Precursor experiments to search for EDMs at COSY 62

PE 1: Use a combination of a snake and RF fields 2 Snake RF E-field Parameters of a proton EDM measurement: Tp=140 MeV ERF=1 MV/m, Lcavity=0.5 m Time of store 24h  6.31010 turns =1 10-7 rad Sensitivity: dp=10-17 ecm  p=5.9 105 s dp=10-18 ecm  p=5.9 107 s P(n) n (number of turns) dp=10-18 ecm dp=10-17 ecm Precursor experiments to search for EDMs at COSY 63

PE 2: Dual Beam Method (equivalent to g-2 d)
It seems possible to store protons and deuterons in COSY simultaneously. p and d at same momentum Polarimeter (determines pp and dp elastic) Assume dp=10-24 ecm. Determine invariant spin axis of protons using polarimeter. Not clear whether one can get away with radial components of P only. Determine invariant spin axis for deuterons using polarimeter. Difference between the two invariant spin axes sensitive to dd. Sensitivity similar to g-2 d: dd=10-19 ecm. Precursor experiments to search for EDMs at COSY 64

PE 3: Resonance Method with RF E-fields (variation of PE1)
spin precession governed by: (* rest frame) Two situations: B*=0  By = ER (= 70 G for ER=30 kV/cm) EDM effect E*=0  ER = - By no EDM effect Polarimeter (dp elastic) stored d RF E-field vertical polarization This way, the Edm signal gets accumulated during the cycle. Statistical improvement over PE 1 is about: Brings us in the ecm range for dd Precursor experiments to search for EDMs at COSY 65

PE 3: Simulation of resonance Method with RF E-fields and deuterons at COSY Parameters: beam energy Td=50 MeV assumed EDM dd=10-20 ecm E-field 10 kV/cm E-field reversed every -/(G)  21 turns Constant E-field Number of turns Number of turns Precursor experiments to search for EDMs at COSY 66

PE 3: Simulation of resonance Method with RF E-fields and deuterons at COSY Parameters: beam energy Td=50 MeV assumed EDM dd=10-20 ecm E-field 10 kV/cm Linear extrapolation of P=sqrt(Px2+Py2) for a time period of sc=1000 s (=3.7108 turns) Number of turns EDM effect accumulates Polarimeter determines Px, Py and Pz Precursor experiments to search for EDMs at COSY 67

Orlov, Morse, Semertzidis PRL 96 (2006)
PE 4: Resonance Method of EDM Measurements in SR Orlov, Morse, Semertzidis PRL 96 (2006) Measurement using an all magnetic ring Sideways P, EDM produces growing Py Using two sub-beams with different v and modulating v allows one to isolate d. Sensitivity dd=10-29 ecm/yr Idea was no longer pursued because systematic error is much larger. Precursor experiments to search for EDMs at COSY 68

Summary Systematic error estimates for all PEs require reliable spin tracking tools. Top priority to make them available ASAP! Next step: Scrutinize potential of different PEs Identify PE with best systematic limit on dp,d. Precursor experiments to search for EDMs at COSY 69

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” Precursor experiments to search for EDMs at COSY 70

Spare transparencies Precursor experiments to search for EDMs at COSY 71 71 71

Frozen Spin Method (FSM)
Lower energy particle …just right Higher energy particle Spin vector Momentum vector Spin coherence time: 103 s for measurement on e·cm level For , the spin precession (magnetic moment) relative to the momentum direction is given by Precursor experiments to search for EDMs at COSY 72

Freezing Spin Precession with E-Fields
G > 0 for γ > 1, if only electric fields are applied Magic momentum for protons: p = MeV/c μp / μN = 2.792 847 356 (23)  Gp = μd / μN = 0.857 438 2308 (72)  Gd = μHe-3 / μN = (25)  G3He= Nuclear magneton: μN = eħ / (2mpc) = 5.050 783 24 (13) · 10-27 J T-1 Precursor experiments to search for EDMs at COSY 73

spin manipulation 180o there is an for every point of the orbit Snakes (non-vertical B field) affect snakes flippers ramping through a resonance reverses spin closed orbit Precursor experiments to search for EDMs at COSY 74

Machine acceptance lost cooled target ring acceptance beam In an ideal machine (like TSR-HD) → Single-Coulomb scattering at the target dominates beam loss K. Grigoriev et al., NIMA 599,130 (2009) Vertical phase space: Ay = 25 π mm mrad, and a beam emittance of εy = 3.8 π mm mrad Precursor experiments to search for EDMs at COSY 75 75

Future: Time Reversal Invariance Test
COSY-TRIC: P-even, T-odd COSY used as accelerator and detector: Total polarization correlation coefficient Ay,xz leads to relative difference of current slopes IBeam time PAX Milestone: Operation of Precision BCT with I/I<10-4 Precursor experiments to search for EDMs at COSY 76

Need for a high precision BCT
Status TRI Test at COSY Slow fluctuations in the measured BCT signal exceed the noise band at higher frequencies Possible solution: Cryogenic Current Comparator, read out by low-temperature super-conducting quantum interference device D. Eversheim Hyperfine Interact 193 (2009) A. Steppke, IEEE Trans. Appl. Superc. (2009) Highest resolution achieved: 250 pA/Hz Precursor experiments to search for EDMs at COSY 77

Mystery of matter-antimatter asymmetry 2 beams simultaneously rotating in a ring (CW, CCW) Approved BNL-Proposal: Goal for protons Circumference ~ 200 m Technological challenges ! Spin coherence time (1000 s) Beam positioning (10 nm) Continuous polarimetry (< 1ppm) E - field gradients (~ 17MV/m at 2 cm) Carry out proof of principle experiments (demonstrators) at COSY Frank Rathmann 19th International Spin Physics Symposium 78 78 78

Limits for Electric Dipole Moments
EDM searches - only upper limits up to now (in ecm): Particle/Atom Current EDM Limit Future Goal  dn equivalent Neutron  3 10-26 10-28 10-28 199Hg  3.1 10-29 10-29 10-26 129Xe  6 10-27 10-30 – 10-33 10-26 – 10-29 Proton  7.9 10-25 10-29 Deuteron ? 3 10-29 – 5 10-33 Kern EDMs können viel größer sein(thoeretische Vorhersage) Huge efforts underway to improve limits / find EDMs Sensitivity to NEW PHYSICS beyond the Standard Model 79 79

Spin Precession Spin precession for particles at rest in electric and magnetic fields: (* 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 JT-1 = Am2 Ecm=Cm=Asm E=1.6*10^-19 Equation for spin motion of relativistic particles in storage rings much more complicated

Search for Electric Dipole Moments
NEW approach: 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, … particle p (GeV/c) E (MV/m) B (T) proton 0.701 16.789 0.000 deuteron 1.000 -3.983 0.160 3He 1.285 17.158 -0.051 One machine with r ~ 30 m 81 81

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  At injection all spin vectors aligned After some time, the spin vectors are all out of phase and in the horizontal plane Longitudinal polarization vanishes! In an EDM machine with frozen spin, observation time is limited. Spin coherence time: 103 s for measurement on e·cm level

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 Spin coherence time depends on dp/p (much better for cooled beams) Sextupole correction of non-linear fields (done next beam time in week 10-19) Is there a difference between spin coherence time w/o RF flipper 5 s 25 s RF solenoid: on off on Spokesperson: E. Stephenson (IUCF)

Resonance Method with RF E(B) Fields
First direct measurement in COSY developed by the Jülich study group Spin precession governed by: Two situations: B*=0  By = ER (= 70 G for ER=30 kV/cm) EDM effect E*=0  ER = - By no EDM effect (* rest frame) Polarimeter (dp elastic) stored d RF E(B)-field vertical polarization Conclusion from simple model: EDM signal is increased during the cycle Statistical sensitivity for dd in the to ecm range possible Simulations of spin dynamics including field errors needed (COSY-Infinity) Alignment and field quality of RF E(B)-flipper crucial

Spin Coherence Time with RF Flipper
Exciting result of the Jülich Study Group Possibility to increase spin coherence time by 3 to 5 orders of magnitude Experiment with polarized COSY beam soon

EDM Cooperation International srEDM Network Institutional (MoU) and Personal (Spokespersons …) Cooperation, Coordination srEDM Collaboration (BNL) srEDM Collaboration (FZJ) Common R & D RHIC EDM-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

Storage ring experiments offer to measure unscreened EDMs
A measurement of n, p, d, 3He EDMs is necessary to understand the underlying physics (Ch.H.) Copied from K. Jungmann

History of neutron EDM limits
Smith, Purcell, Ramsey PR 108, 120 (1957) RAL-Sussex-ILL (dn  2.9 10-26 ecm) PRL 97, (2006) Adopted from K. Kirch

Why also EDMs of protons and deuterons?
Proton and deuteron EDM experiments may provide one order higher sensitivity In particular the deuteron may provide a much higher sensitivity than protons Consensus in the theoretical community: Essential to perform EDM measurements on different targets (p, d, 3He) with similar sensitivity to unfold the underlying physics and to explain the baryogenesis.

Frozen Spin Method (FSM)
Lower energy particle …just right Higher energy particle Spin vector Momentum vector Spin coherence time: 103 s for measurement on e·cm level For , the spin precession (magnetic moment) relative to the momentum direction is given by

Spin Motion in Storage Rings
For the case of , the spin precession relative to The momentum direction is given by , where is the rotation about the vertical B-field direction that arises because there is an anomalous part to the magnetic moment. The frequency about the radial direction (for Spin-1 particles S=1) is

Systematic Effects Most serious systematic effect: non-zero average value for the vertical component of the electric field Radial precession The ratio of the spin precession (due to the vertical electric field) to the EDM spin precession Needs to be minimized If, for example, we already know that the dEDM < 3 · 10−25 e · cm, the vertical electric field needs to cancel up to the level <Ev>/ ER ≤ 10−10 in every fill  Field stability, ground motion, temperature stability W-ev canges sign relatic to w-edm for CW vs. CCW beams This gives an average radial magnetic field in the particle’s rest which precesses the spin about the radial direction: ωEV = geEV 2mcβγ2 . (47) This is the only first order spin dynamics systematic error, i.e. this error by itself produces a systematic effect. The precession ωEV , relative to ωedm, changes sign when we inject the beam clock-wise (CW) vs. counter-clockwise (CCW). The EDM signal is a difference in the measured deuteron spin precession about the radial direction when injecting CW vs. CCW. Without this symmetry, EV /E0 < 5 × 10−15 would be required for an EDM systematic error of 10−29 e ·cm.

Two EDM Storage Ring Projects
Copied from R. Talman Copied from A. Lehrach

EDM Projects R&D Activity Goal Test Internal Polarimeter
Light-Ion EDM Jülich Proton EDM BNL R&D Activity Goal Test Internal Polarimeter spin as a function of time Systematic errors < 1 ppm EDM at COSY Full-scale polarimeter Spin Coherence Time >103 s Beam Position Monitor resolution 10 nm,1 Hz BW 64 BPMs, 107 s measurement time  1 pm (stat.) relative position (CW-CCW) BNL RHIC IP EB-field Deflector 17 MV/m 2 cm plate separation, T Jülich The experiment requires knowledge of the relative positions of the two counter rotating beams at the level of m if magnetic focusing is used and m if purely electrostatic focusing is implemented. Statistical averaging over the running time. Systematic errors to be demonstrated A resonant BPM located at the interaction point of the CW and CCW beams can be made very sensitive to the separation of the two beams (Coincident BeamS: CBS)  needed information is relative 64 BPMs, cum. meas. time 107 seconds  statistical error ±1pm BPMs: 10 nm, 1Hz BW resolution, syst. < 1pm on relative (between the two counterrotating beams) position. A radial B-field of 0.2pG will split the counter-rotating proton beams vertically by ~1pm. It will precess the proton spin just like an EDM (10-29 e-cm) 10 MeV e-beams will split by ~0.1nm (P. Thieberger). Erdmagnetfeld: In Mitteleuropa sind es ca. 48 µT, wobei ca. 20 µT in der horizontalen und ca. 44 µT in der vertikalen Richtung auftreten  Zum Beispiel ist das Erdmagnetfeld von der Größenordnung 1 Gauß (100 µT) YKS: Doesn’t look impossible Polarimeter systematic errors to 1ppm (early to late times-not absolute!). The EDM signal is ~3ppm early to late change in (L-R)/(L+R) counts. Due to beam momentum spread dP/P there is spread in the horizontal spin precession. The linear part of the spread is canceled by using RF-cavity. The quadratic part by using compensating sextupole magnets. We expect to demonstrate (with simulation) ~103s by end of 2010 using realistic fields.

List of Activities (Accelerator)
Prototype E-B Deflectors ARD (Accelerator Research and Development) proposal to the HGF Layout: Field calculations to optimize the coil and conductor plate Design: Mechanical design of the deflector Prototype: Development of a deflector prototype Test bench: Study field quality and stability Prototype BPM (BNL for CW-CCW beams) Beam and Spin Simulations COSY Infinity Code: Beam simulation for COSY ring started Full spin tracking simulations needed The argument that spin precession effects in horizontal magnetic field components sampled in quadrupoles must average to zero if the beam is to be maintained stably in the stored orbit could potentially be compromised if the polarimeter preferentially samples beam particles most likely to leave the ring acceptance. COSY Infinity: - The Differential Algebraic types for high-order multivariate study of ODEs, Flows, and PDEs. Also allow high-order multivariate automatic differentiation. The Taylor Model type for rigorous high-order computing with often far-reaching suppression of dependency. Tools for range bounding, derivative-based box rejection, constraint satisfaction, ODEs and PDEs. Analysis options include computation of high-order nonlinearities; analysis of properties of repetitive motion via chromaticities, normal form analysis, and symplectic tracking; analysis of single-pass systems resolutions, reconstructive aberration correction, and consideration of detector errors; and analysis of spin dynamics via computation of spin maps, spin normal form and spin tracking.

Simulation of Spin Rotations
Parameters: beam energy Td=50 MeV assumed EDM dd=10-20 ecm E-field 10 kV/cm E-field reversed every -/(G)  21 turns Linear extrapolation of for a time period of sc=1000 s (=3.7108 turns) Number of turns EDM effect accumulates Polarimeter determines Px, Py and Pz Number of turns Courtesy: F. Rathmann

3 ON-OFF-ON runs had usable data. “No lattice” model in which betatron
WE-Heraeus Seminar: Search for EDMs at Storage Rings Physikzentrum Bad Honnef, July 4-6, 2011 17 3 ON-OFF-ON runs had usable data. “No lattice” model in which betatron oscillation effects included by a path lengthening mechanism, scaled to match the measured emittance. Band represents Monte Carlo errors for 1000 particles in model. Using a Gaussian shape, “half life” represented by this point is 75 s. We could not have seen this effect for uncooled beam as synchrotron oscillations inside beam bunch damped reference oscillation pattern. Curve is “no lattice” model. Expected half life 5-10 s.

Distribution of synchrotron amplitudes
WE-Heraeus Seminar: Search for EDMs at Storage Rings Physikzentrum Bad Honnef, July 4-6, 2011 18 Distribution of synchrotron amplitudes 3 ON-OFF-ON runs had usable data. Cooled Uncooled

Distribution of synchrotron amplitudes
WE-Heraeus Seminar: Search for EDMs at Storage Rings Physikzentrum Bad Honnef, July 4-6, 2011 19 Distribution of synchrotron amplitudes 3 ON-OFF-ON runs had usable data. Cooled Uncooled

t t=L/v

Mystery of matter-antimatter asymmetry EDM searches - only upper limits up to now: Huge efforts under way to improve limits / find EDMs Sensitivity to NEW PHYSICS beyond the Standard Model 485. WE-Heraeus-Seminar (July 0406, 2011) Search for Electric Dipole Moments (EDMs) at Storage Rings Precursor experiments to search for EDMs at COSY 109 109 109

Sensitivity of an EDM Experiment
P = Beam polarization A = 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 Yannis Semertzidis, BNL 110 110

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

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