1. ICNPF 2013, Crete, Aug. 28 – Sept. 5, 2013
JEDI - The Jülich Electric Dipole Moment Investigations in Storage Rings
| H. Ströher

2. The European Strategy for Particle Physics, Update 2013
EDM – A Top Priority
Recommendations
EDM
The European Strategy for Particle Physics, Update 2013

3. SNOWMASS Meeting, August 2013 (US HEP Community)
EDM – A Top Priority
SNOWMASS Meeting, August 2013 (US HEP Community)

4. EDMs can contribute to many of the „Big Questions“
EDM – A Top Priority
EDMs can contribute to many of the „Big Questions“

5. EDM – Estimate of the Scale
Size of the nucleon:
D = 1 fm = cm
d = e cm
Nature violates parity  price to pay: ~ 10-7
Nature violates CP  price to pay: ~ 10-3
EDM < e cm
Electric dipole moments are very small  precision experiments

6. EDM – Current Upper Limits
natural
scale
EDM upper limits (e cm)
New:
Charged
Hadrons
e m t n p L d
in atom in atom
EDMs will have a huge impact on „Physics beyond the SM“

7. EDM – Ongoing/planned Searches
new
P. Harris, K. Kirch … A huge worldwide effort

8. EDM – Ongoing/planned Searches
nEDM: aim at sensitivity of a few times e cm

9. EDM – Points to Remember
EDM (searches)
for charged-particles: use of polarized beams in storage ring(s)
EDM (searches)
EDM (searches)
have an exceptional physics case
are very hard to measure
(in fact, none observed so far!)
„JEDI“ (Jülich Electric Dipole Moment Investigations) w/i JARA|Fame

10. AMS (not discussed further) and EDM
EDM – Larger Scope
The
Fate of
Anti-
matter
Search
for it !
It´s gone
– why ?
AMS
EDM
AMS (not discussed further) and EDM

11. EDM – Measurement Principle (I)B E B E
f+ = 2µB` + 2dE`
µ d
f- = 2µB` - 2dE`
Precession frequency (difference)  example: neutron

12. EDM – Measurement Principle (II)
Spin
Momentum
„Freeze“
horizontal spin
of polarized
charged particle beam
in storage ring
along the
momentum, …
Momentum and polarization vector

13. EDM – Measurement Principle (II)
Spin
Momentum
„Freeze“
horizontal spin
of polarized
charged particle beam
in storage ring
along the
momentum, …
… after one turn …

14. EDM – Measurement Principle (II)
Spin
Momentum
„Freeze“
horizontal spin
of polarized
charged particle beam
in storage ring
along the
momentum, …
Polarization vector points in different direction („spin tune“)

15. EDM – Measurement Principle (II)
„Freeze“
horizontal spin
of polarized
charged particle beam
in storage ring
along the
momentum, …
„Frozen spin“ (particle momentum and E- and B-fields)

16. EDM – Measurement Principle (II)
Application of a radial electric field (E):
Torque: t ~ d x E
(if EDM is non-zero)
Goal:
10-29 e cm
– a challenge !
Observable: development of vertical polarization

17. EDM – Charged Particles in SRs
An incomplete list of challenges

18. EDM – Charged Particles in SRs
COSY (Cooler Synchrotron) at FZ-Jülich
184 m
JEDI („Jülich Electric Dipole Moment Investigations“)

19. EDM – Charged Particles in SRs
COSY (Cooler Synchrotron) at FZ-Jülich
Polarized proton, deuteron beams
Momentum range 0.3 to 3.7 GeV/c
Electron and stochastic cooling
Internal targets and detectors
Spin manipulators:
RF solenoid, RF dipole, Siberian Snake
Polarimeter
 Best possible starting point for srEDM
JEDI („Jülich Electric Dipole Moment Investigations“)

20. EDM – Charged Particles in SRs
COSY (Cooler Synchrotron) at FZ-Jülich
EDM Sensitivity
10-29 e cm
Dedicated SR
First direct
measurements
for p, d
10-24 e cm
Precursor expt. w/ COSY
R&D, test measurements at COSY
Time
Now
JEDI („Jülich Electric Dipole Moment Investigations“)

21. EDM – Charged Particles in SRs
Polarimetry
Tests with an existing polarimeter (EDDA) at COSY:
Beam onto a C-target; spin-dependent scattering
Proof of principle - required accuracy achieved
Results (NIM A 664 (2012) 49); systematic errors < 1ppm
Stage 1: Ongoing R&D at COSY

22. EDM – Charged Particles in SRs
Spin Tune Measurements
~ 1.2 x 107
~ 7 x 107
Deviation
~ 25 ppb
Stage 1: Ongoing R&D at COSY

23. EDM – Charged Particles in SRs
Spin Coherence Time (SCT) Optimization
Tests with an existing polarimeter (EDDA) at COSY:
Longitudinal spin decoherence (due to beam oscillations)
Decoherence compensated by tuning sextupole magnets
Result: SCT of ~ 200 s have already been achieved
Stage 1: Ongoing R&D at COSY

24. EDM – Charged Particles in SRs
Electrostatic Deflectors
Replace D2-magnet by
electrostatic deflector
L~2.5 m
Tests with existing equipment from Tevatron (Fermi Lab, USA):
Routine operation at 1 spark/year at 6 MV/m at Tevatron
Transfer to Jülich, reproduce and improve (w/ ZEA, RWTH)
Installation into COSY (option): B-E-B chicane
Stage 1: Ongoing R&D at COSY

25. EDM – Charged Particles in SRs
Precursor Experiment at COSY
Proof-of-principle with existing (conventional) storage ring COSY:
Modifications of COSY (ANKE, PAX, WASA, … out)
Power supply stabilization; beam position monitors …
„Magic“ RF Wien-filter (E-B field):
Stage 2: pEDM and/or dEDM  e cm

26. EDM – Charged Particles in SRs
Precision EDM Storage Ring
Technical design criteria:
Counter-rotating (CW, CCW) beams
pEDM: all-electric ring possible:
(p, d, 3He, …)EDM: combined electric and magnetic fields
Stage 3: Dedicated storage ring (with COSY as injector)

27. EDM Project within JARA|FAME („JEDI“)
EDM – Summary
EDM (searches)
have an exceptional physics case
are very hard to measure
for charged-particles: use of polarized beams in storage ring(s):
Jülich is the „best place on earth“
EDM Project within JARA|FAME („JEDI“)