1. Storage ring EDM experiments Yannis Semertzidis, CAPP/IBS and KAIST
12 September 2015
Flavour workshop, Capri/Italy
Storage ring EDM experiments Yannis Semertzidis, CAPP/IBS and KAIST
Center for Axion and Precision Physics (CAPP) in Korea
Axion dark matter search:
State of the art axion dark matter experiment in Korea. State of the art axion search.
Precision physics frontier
Muon g-2, COMET, etc.
Storage ring EDMs, probing NP ~ TeV

2. Center for Axion and Precision Physics (CAPP)
CAPP / IBS, October 2014

3. CAPP / IBS, May 2015

5. Positions/opportunities
Young Scientists (YS)
Received Ph.D. within the last five years
Great promise
Have an idea and a center is endorsing him/her
Funding: 300 M KRW/year for five years (1$~1,200KRW)
The project should be possible to complete in five years with said funding levels

6. Positions/opportunities (Cont’d)
Senior Scientists (SS)
Received Ph.D. more than five years ago
Accomplished scientist
Have an idea and a center is endorsing him/her
Funding: 500 M KRW/year for three years
The project should be possible to complete in three years with said funding levels

7. The EDM effort 7

8. Electric Dipole Moments: P and T-violating when // to spin
T-violation: assuming CPT cons.  CP-violation

9. Why is there so much matter after the Big Bang:
We see:
From the SM:

10. Proton storage ring EDM experiment is combination of beam + a trap
B. Morse

11. Storage ring EDM method
Or… how do you turn a weakness into an opportunity?

12. Yannis Semertzidis, CAPP/IBS, KAIST
Stored beam: The radial E-field force is balanced by the centrifugal force. E
Yannis Semertzidis, CAPP/IBS, KAIST
Yannis Semertzidis, BNL 12

13. Support letter to P5 for the proton EDM

14. P5: Particle Physics Project Prioritization Panel setup by DOE and NSF
P5: Particle Physics Project Prioritization Panel setup by DOE and NSF. It took more than a year for the HEP community to come up with the report.
In 2014 we have received the P5 endorsement for the proton EDM experiment under all funding scenarios!

15. The Electric Dipole Moment precesses in an Electric field
Yannis Semertzidis

16. Yannis Semertzidis, CAPP/IBS, KAIST
The proton EDM uses an ALL-ELECTRIC ring: spin is aligned with the momentum vector
at the magic momentum E
Momentum
vector
Spin vector
Yannis Semertzidis, CAPP/IBS, KAIST
Yannis Semertzidis, BNL 16

17. The proton EDM ring (alternate gradient)
Straight sections are instrumented
with quads, BPMs, polarimeters,
injection points, etc, as needed.
Requirements:
Weak vertical focusing (B-field
sensitivity)
Below transition (reduce IBS)

18. Proton Statistical Error (230MeV):
p : 103s Polarization Lifetime (Spin Coherence Time)
A : Left/right asymmetry observed by the polarimeter
P : Beam polarization
Nc : 1011p/cycle Total number of stored particles per cycle
TTot: 107s Total running time per year
f : 1% Useful event rate fraction (efficiency for EDM)
ER : 5 MV/m Radial electric field strength
σd = 1.4×10-29 e-cm / year
Yannis Semertzidis, BNL 18

19. Systematic errors

20. Clock-wise (CW) & Counter-Clock-wise Storage
Total current: zero. Any radial magnetic field in the ring sensed by the stored particles will cause their vertical splitting.
Simultaneous proton-proton storage 20

21. Distortion of the closed orbit due to Nth-harmonic of radial B-field
Clockwise beam
Y(ϑ)
The N=0 component
is a first order effect!
Counter-clockwise
beam
Time [s]

22. SQUID BPM to sense the vertical beam splitting at 1-10kHz

23. Total noise of (65) commercially available SQUID gradiometers at KRISS
From YongHo Lee’s group
KRISS/South Korea

24. Peter Fierlinger, Garching/Munich
Under development by
Selcuk Haciomeroglu
at CAPP. Need <0.1nT/m

25. Peter Fierlinger, Garching/Munich
Shipped to Korea for integration
Yannis Semertzidis, CAPP/IBS, KAIST

26. Proton EDM animation

27. What has been accomplished?
Polarimeter systematic errors (with beams at KVI, and stored beams at COSY).
Precision beam/spin dynamics tracking.
Stable lattice, IBS lifetime: ~104s (Lebedev, FNAL)
Spin coherence time 103 s; role of sextupoles understood (using stored beams at COSY).
Feasibility of required electric field strength <5 MV/m, 3cm plate separation (JLab, FNAL)
Analytic estimation of electric fringe fields and precision beam/spin dynamics tracking. Stable!
(Paper already published or in progress.)

28. The storage ring Proton
Major characteristics of a successful Electric Dipole Moment Experiment
Statistical power:
High intensity beams
Long beam lifetime
Long Spin Coherence Time
An indirect way to cancel B-field effect
A way to cancel geometric phase effects
Control detector systematic errors
Manageable E-field strength, negligible dark current
The storage ring Proton
EDM method has it all!

29. Electric Dipole Moments in Magnetic Storage Rings
e.g. 1 T corresponds to 300 MV/m for
relativistic particles
Yannis Semertzidis

30. Two different labs could host the storage ring EDM experiments
COSY/IKP, Jülich/Germany: deuteron or a combination ring
AGS/BNL, USA: proton “magic” (simpler) ring
Opportunity opening
for another lab!

31. Various options for EDM@COSY, Juelich

32. Marciano, CM9/KAIST/Korea, Nov 2014

33. Let’s indulge on proton sensitivity
Spin coherence time (104 seconds), stochastic cooling-thermal mixing, …
Higher beam intensity, smaller IBS
Reliable E-field 15 MV/m with negligible dark current
>5% efficient polarimeter, run longer
Potential gain >102 in statistical sensitivity: ~ e-cm!

34. Statistics limited Sensitivity to Rule on Several New Models
Baryogenises
Electroweak
GUT SUSY
Gray: Neutron
Red: Electron
If found it could explain
Baryogenesis (p, d, n, 3He)
n current
e current
n target
p, d target
e target
1st upgrade
Statistics limited
Electron EDM new physics reach: 1-3 TeV
Much higher physics reach
than LHC; complementary
e-cm
J.M.Pendlebury and E.A. Hinds, NIMA 440 (2000) 471

35. EDM status The EDM experiments are gearing up, getting ready:
199Hg EDM <10-29 e-cm sensitivity, imminent
nEDM at PSI e-cm sensitivity,
nEDM at PSI e-cm sensitivity, …
nEDM at SNS ~2×10-28 e-cm starting data taking 2021

36. EDM status (cont’d)
ThO, current limit on eEDM: e-cm, next ×10 improvement.
TUM nEDM effort, making progress in B-field shielding, met B-field specs. It moves to ILL in 2015, goal: e-cm, staged approach, starting in 2016.
225Ra EDM, ~5×10-22 e-cm now, ~3×10-28 e-cm w/ FRIB
Storage ring EDM: p,dEDM goals ~10-29 e-cm Strength: statistics. Proton w/ upgrade ~10-30 e-cm

37. The Storage Ring electron EDM What can we learn from it?37

38. Storage ring electron EDM
All electric ring: electron “magic” momentum: 15MeV/c
Originally proposed by Yuri Orlov, circa 2004
Polarimeter was the major issue
Bill Morse developed on eEDM concepts, 2013
Beam-beam scattering major issue (Valerie Lebedev)
Richard Talman, 2015: use resonant polarimeter combined with Koop’s spin wheel. Potentially a game changer…! 38

39. Richard Talman’s electron polarimeter concept
eEDM: Potentially systematics
limited at below 10-27e.cm!
arXiv: 39

40. Build an electron storage ring
Start simple. Run it with CW and CCW stored beams (all-electric) at magic momentum. Simulate storage ring proton EDM. Limited Physics reach on eEDM. Great for systematics studies on the Storage ring proton EDM.
Run it in Talman’s configuration (spin-wheel with resonant electron-polarimeter) at magic momentum. EDM sensitivity (if limited by systematics: B-field stability) <10-27e.cm
Run it in Morse’s configuration (combined electric and magnetic fields) below magic momentum. EDM sensitivity (if limited by systematics) <10-29e.cm 40

41. Summary Storage ring EDM effort is timely
Start simple: all electric, study all-electric ring concepts with electrons
Apply all-electric-field configuration combining spin wheel and resonant polarimeter
Apply combined ring configuration with spin wheel and resonant polarimeter.
Ultimate sensitivity for e, p, d < e-cm

42. Extra slides

43. What can we learn from a storage ring electron EDM: all electric
Probe the free-electron EDM with high accuracy
“Learn by doing”, a working prototype of a large ring. Install sextupoles to prolong SCT.
Learn about E-field alignment issues as well as stability issues. 43

44. What can we learn from a storage ring electron EDM: all electric
Study fringe-field effects on SCT & storage time.
Study wake field issues (beam impedance), coupled with RF-cavity misalignment. 44

45. What can we learn from a storage ring electron EDM: all electric
Store simultaneous CW & CCW beams. Modulate vertical focusing strength. Install SQUID-based BPMs. Study the effects of external B-fields (stability issues, detection sensitivity).
Install B-field shielding and exercise feedback system (B-field cancellation system). 45

46. What can we learn from a storage ring electron EDM: combined ring
Study all issues related with combined E and B-fields, e.g., fringe-field effects, local cancellations, geometrical phases, low energy e-trapping… Test the storage ring deuteron EDM concepts!
Probe the electron EDM with high accuracy, better than 10-29e.cm. 46

47. Opportunities for new collaborators
Electric field strength issues for large surface plates, dark currents
Beam-based alignment, E-field plate alignment (pot. syst. error source)
Beam impedance issues (pot. syst. error source)

48. Technically driven pEDM timeline
2014 15 16 17 18 19 20 21 22 23
Two years systems development (R&D); CDR; ring design, TDR, installation
CDR by end of 2016
Proposal to a lab: fall 2016
Yannis Semertzidis, CAPP/IBS, KAIST