The Storage Ring Proton EDM experiment Yannis Semertzidis, CAPP /IBS at KAIST

1. 23 July 2014 Lepton Moments, Cape Cod The Storage Ring Proton EDM experimentYannis Semertzidis,CAPP/IBS at KAIST Strong CP-Problem • Axion dark matter search: • State of the art axion dark matter experiment in Korea • Collaborate with ADMX, CAST… • Proton Electric Dipole Moment Experiment • Storage ring proton EDM • Muon g-2, mu2e, etc.

2. Korean Alphabet (Hangul, 1443AD) • 24 characters, consonants and vowels • Easy to read, understand short sentences, orient yourself at public places • Hard to understand complicated sentences • Many people understand English

3. Center for Axion and Precision Physics Research: CAPP/IBS at KAIST, Korea • Four groups • 15 research fellows, ~20 graduate students • 10 junior/senior staff members, Visitors • Engineers, Technicians • Future: IBS building at KAIST

4. CAPP Group Three more Research Fellows signed up already… http://capp.ibs.re.kr/html/capp_en/

5. Storage Ring Proton EDM

6. Proton storage ring EDM experiment is combination of beam + a trap

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

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

9. The proton EDM ring Total circumference: 300 m Bending radius: 40 m Straight sections are instrumented with quads, BPMs, polarimeters, injection points, etc, as needed.

10. Feasibility of an all-electric ring • Two technical reviews have been performed at BNL: Dec 2009, March 2011 • Fermilab thorough review. Val Lebedev considers the concept to be sound. • First all-electric ring: • AGS-analog • Ring radius 4.7m • Proposed-built 1953-57 • It worked!

11. srEDM International Collaboration • COSY: • Strong collaboration with Jülich/Germany continues • We’ve been doing Polarimeter Development, Spin Coherence Time benchmarking, Syst. Errors, Beam/Spin dynamics simulation, etc. for >5 years w/ stored pol. beams. • JLAB: breakthrough work on large E-Fields • KOREA: • We are forming the EDM group and getting started with system developments. • ITALY (Ferrara, Frascati,…) • TURKEY (ITU,…) • GREECE (Demokritos, …) Three PhDs already: KVI, Ferrara, ITU

12. The proton EDM ring evaluation Val Lebedev (Fermilab) Beam intensity 1011 protons limited by IBS , kV

13. pEDM polarimeter principle (placed in a straight section in the ring): probing the proton spin components as a function of storage time Micro-Megas detector, MRPC or Si. “defining aperture” polarimeter target Extraction: lowering the vertical focusing carries EDM signal increases slowly with time carries in-plane (g-2) precession signal

14. Polarimeter design, rates: Beam rates ~102 Hz/cm2 on average, higher at small radius. Design: ~1KHz/pad. Store bunches with positive/negative helicity for pol. syst. errors. 70 cm

15. The EDM signal: early to late change • Comparing the (left-right)/(left+right) counts vs. time we monitor the vertical component of spin M.C. data (L-R)/(L+R) vs. Time [s] Opposite helicity bunches result to opposite sign slopes

16. Large polarimeteranalyzing power at Pmagic!

17. Our proton EDM plan • Develop the following systems (funded by IBS/Korea, COSY/Germany, applying for NSF support, and DOE-HEP/NP): • SQUID-based BPM prototype, includes B-field shielding (UMass, CAPP/Korea, BNL,…) • Polarimeter development (Ind. Univ., CAPP, COSY,…) • Electric field prototype (Old Dom. Un. (NSF), JLab,…) • Study of systematic errors (BNL, FNAL, Cornell,…) • Precision beam and spin dynamics simulation (BNL, CAPP, Cornell, COSY,…) • Lattice optimization, beam diagnostics (MSU (NSF),…)

18. Clock-wise (CW) & Counter-Clock-wise Storage Any radial magnetic field sensed by the stored particles will also cause their vertical splitting. Unique feature among EDM experiments… Equivalent to p-bar p colliders in Magnetic rings

19. 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]

20. Noise level: 0.9 fT/√Hz Vertical tune modulation frequency: 10 kHz

21. SQUID gradiometers at KRISS

22. SQUID gradiometers at KRISS

24. B-field Shielding Requirements • No need for shielding: In principle, with counter-rotating beams. • However: BPMs are located only in straight sections sampling finite. Nyquist theorem limits sensitivity to low harmonics of Br. Hence the B-field needs to be less than (1-10nT) everywhere to reduce its effect. We are building a prototype!

25. Peter Fierlinger, Garching/Munich Issues: demagnetization, effect of holes, etc.

26. Peter Fierlinger, Garching/Munich

27. International srEDM NetworkCommon R&D • srEDM Coll. pEDM • Proposal to DOE HEP, NP • SQUID-based BPMs • B-field shielding/compensation • Precision simulation • Systematic error studies • E-field tests • … • JEDI (COSY/Jülich) • Pre-cursor EDM exp. • Polarimeter tests • Spin Coherence Time tests • Precision simulation • Cooling • E-field tests • …

28. 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: 7500s. • Spin coherence time >300s, role of sextupoles (with stored beams at COSY). • Feasibility of required electric field strength ~40kV/cm – 100kV/cm, 3cm plate separation • Analytic estimation of electric fringe fields and precision beam/spin dynamics tracking. Stable! • Already published or in progress.

29. Tracking results using realistic (analytic estimations of) fringe fields The radial position away from the ideal orbit as a function of ring X and Y coordinates. E. Metodiev et al., to appear in PRSTAB

30. Jlab E-field breakthrough • Large grain Nb, no detectable dark current up to (max avail.) 18 MV/m and 3cm plate gap • TiN coated Al plates reach highE-field strength • Jlabto develop large surface plates

31. Field Emission from Niobium Work of M. BastaniNejad • Phys. Rev. ST Accel. Beams, 15, 083502 (2012) Buffer chemical polish: less time consuming than diamond paste polishing Fine grain niobium DPP stainless steel Single crystal niobium Large grain niobium Field strength > 18 MV/m Conventional High Voltage processing: solid data points After Krypton Processing: open data points

32. What about TiN-coated Aluminum? No measureable field emission at 225 kV for gaps > 40 mm, happy at high gradient Bare Al TiN-coated Al the hard coating covers defects Work of Md. A. Mamun and E. Forman

33. Technically driven pEDM timeline 16 19 13 14 15 17 18 20 21 22 • Two years system development • One year final ring design • Three years beam-line construction and installation

34. EDMs: Storage ring projects pEDM in all electric ring in the USA Jülich, focus on deuterons, or a combinedmachine CW and CCW propagatingbeams (from A. Lehrach)

35. The Proton EDM experiment status • Support for the proton EDM: • CAPP/IBS, KAIST in Korea, R&D support for SQUID-based BPMs, Prototype polarimeter, Spin Coherence Time (SCT) simulations. • COSY/Germany, studies with stored, polarized beams, pre-cursor experiment. • After the P5 endorsement DOE-HEP requested a white paper to establish the proton EDM experimental plan. • Large ring radius is favored: Lower E-field strength required, Long SCT, 1-10nT B-field tolerance in ring. Use of existing ring preferred.

36. The JEDI experiment status • Helmholtz Foundation evaluation, early 2014. • The pre-cursor experimental program is approved: Use of the existing COSY ring, slightly modified to become sensitive to deuteron EDM (RF-Wien filter). • EDM sensitivity moderate, but significant as first direct measurement. • Asked to prepare a CDR for a sensitive storage ring EDM experiment.

37. Summary • The storage ring proton EDM has been developed. The breakthrough? Statistics! • Best sensitivity hadronic EDM method. • Both efforts (USA and COSY) received encouragement to produce an experiment plan. • pEDM first goal 10-29ecm with a final goal 10-30 ecm. Complementary to LHC; probes New Physics ~102-103TeV.

38. Extra slides

39. Peter Fierlinger, Garching/Munich

41. Why now? • Exciting progress in electron EDM using molecules. • Several neutron EDM experiments under development to improve their sensitivity level. • Proton EDM could be decisive to clarify the picture.

42. Storage ring proton EDM method • All-electric storage ring. Strong radial E-field to confine protons with “magic” momentum. The spin vector is aligned to momentum horizontally. • High intensity, polarized proton beams are injected Clockwise and Counter-clockwise with positive and negative helicities. Great for systematics • Great statistics: up to ~1011 particles with primary proton beams and small phase-space parameters.

43. Large Scale Electrodes, New: pEDM electrodes with HPWR

44. Physics reach of magic pEDM (Marciano) The proton EDM at 10-29e∙cm has a reach of >300TeV or, if new physics exists at the LHC scale, <10-7-10-6 rad CP-violating phase; an unprecedented sensitivity level. The deuteron EDM sensitivity is similar. • Sensitivity to new contact interaction: 3000 TeV • Sensitivity to SUSY-type new Physics:

45. The grand issues in the proton EDM experiment • BPM magnetometers (need to demonstrate in a storage ring environment) • Polarimeter development: high efficiency, small systematic errors • Spin Coherence Time (SCT): study at COSY/simulations; Simulations for an all-electric ring: SCT and systematic error studies • Electric field development for large surface area plates

46. 1. Beam Position Monitors • Technology of choice: Low Tc SQUIDS, signal at 102-104Hz (10% vertical tune modulation) • R&D sequence: • Operate SQUIDS in a magnetically shielded area-reproduce current state of art • Operate in RHIC at an IP (evaluate noise in an accelerator environment); • Operate in E-field string test

47. 2. Polarimeter Development • Polarimeter tests with runs at COSY (Germany) demonstrated < 1ppm level systematic errors: N. Brantjes et al., NIM A 664, 49, (2012) • Technologies under investigation: • Micro-Megas/Greece: high rate, pointing capabilities, part of R&D for ATLAS upgrade • MRPC/Italy: high energy resolution, high rate capability, part of ALICE development

48. 3. Spin Coherence Time: need >102 s • Not all particles have same deviation from magic momentum, or same horizontal and vertical divergence (all second order effects) • They cause a spread in the g-2 frequencies: • Present design parameters allow for 103s. Cooling/mixing during storage could prolong SCT (upgrade option?).

49. The miracles that make the pEDM • Magic momentum (MM): high intensity charged beam in an all-electric storage ring • High analyzing power: A>50% at the MM • Weak vertical focusing in an all-electric ring: SCT allows for 103s beneficial storage; prospects for much longer SCT with mixing (cooling and heating) • The beam vertical position tells the average radial B-field; the main systematic error source