1. NuFact 2012
Williamsburg, July 2012
Storage ring  Electric Dipole Moment experiment for the proton Yannis K. Semertzidis, BNL
Goal: 10-29e·cm; Probe New Physics ~103 TeV
Can probe fine-tuned SUSY (>>1TeV)
Systematics best in an all-electric ring and counter-rotating (CR) beams.

2. Why is there so much matter after the Big Bang;
We observe:
From the SM:

3. The night sky according to the standard Model (SM)
Very little matter survives annihilation with the anti-matter

4. The night sky as observed:
The great mystery in our Universe: matter dominance over anti-matter.
EDMs could point to a strong CP-violation source capable of creating the observed asymmetry.

5. Electric Dipole Moment: two possibilities- + + -

6. If we discover that the proton
Has a non-zero EDM value, i.e. prefers only one of the two possible states: + - - +
Then P and T symmetries are violated and through CPT, CP-symmetry is also violated.
CP-violation is one of three necessary conditions to obtain a matter dominated universe starting from a symmetric one…

7. Purcell and Ramsey: “The question of the possible existence of an electric dipole moment of a nucleus or of an elementary particle…becomes a purely experimental matter”
Phys. Rev. 78 (1950)

8. 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 (or 3He))
n current
e current
n target
p, d target
e target
Upgrade possibility
Statistics limited
If a pEDM is not found it can
eliminate EW-Baryogenesis
e-cm
J.M.Pendlebury and E.A. Hinds, NIMA 440 (2000) 471

9. The Electric Dipole Moment precesses in an Electric field
The EDM vector d is along the particle spin direction + -

10. A charged particle between Electric Field plates would be lost right away…- + +
Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 10

11. Yannis Semertzidis, BNL
…but can be kept in a storage ring for a long time. The radial E-field is balanced by the centrifugal force. E
Yannis Semertzidis, BNL
Yannis Semertzidis, BNL 11

12. Yannis Semertzidis, BNL
The proton EDM uses an ALL-ELECTRIC ring: spin is aligned with the momentum vector
At the magic momentum E
Momentum
vector
Spin vector
the spin and momentum
vectors precess at same
rate in an E-field
High Intensity: 1011 per pulse! (Proton beams come from primary sources)
Yannis Semertzidis, BNL
Yannis Semertzidis, BNL 12

13. Muon g-2: Precision physics in a Storage Ring
Statistics limited… to improve sensitivity by a factor of 4 at Fermilab
Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

14. Muon g-2: 4 Billion e+ with E>2GeV
Sub-ppm accuracy,
statistics limited
Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

15. Breakthrough concept: Freezing the horizontal spin precession due to E-field
Muon g-2 focusing is electric: The spin precession due to E-field is zero at “magic” momentum (3.1GeV/c for muons, 0.7 GeV/c for protons,…)
The “magic” momentum concept was used in the muon g-2 experiments at CERN, BNL, and …next at FNAL.

16. The proton EDM ring Weak vertical focusing to optimize
As shown on the March 2011 review
with limited straight-section length
Weak vertical focusing to optimize
SCT and BPM operation
B: quadrupoles

17. 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 17

18. The miracles that make the pEDM
Magic momentum (MM): high intensity (1011) 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
The beam vertical position tells the average radial B-field; the main systematic error source

19. A proposed proton EDM ring location
at BNL. It would be the largest diameter
all-electric ring in the world.
Booster
AGS

20. EDMs of hadronic systems are mainly sensitive to
Theta-QCD (part of the SM)
CP-violating sources beyond the SM
Alternative simple systems are needed to be able to differentiate the CP-violating source (e.g. neutron, proton, deuteron,…).
pEDM at 10-29ecm is > an order of magnitude more sens. than the best current nEDM plans

21. Physics reach of pEDM Sensitivity to new contact interaction: 103 TeV
Sensitivity to SUSY-type new Physics:
The proton EDM has a reach of >300 TeV or, if new physics exists at the LHC scale, <10-6 rad CP-violating phase; an unprecedented sensitivity level.
The deuteron EDM sensitivity is similar. 21

22. Yannis Semertzidis, BNL
Why does the world need a Storage Ring EDM experiment at the e-cm level ?
The proton, deuteron and neutron combined can pin-down the CP-violating source should a non-zero EDM value is discovered. Critical: they can differentiate between a theta-QCD source and beyond the SM.
The proton and deuteron provide a path to the next order of sensitivity.
Yannis Semertzidis, BNL

23. Total cost: exp + ring + beamline for two different ring locations @ BNL
System
Experiment w/ indirects
Conventional plus beamline w/ indirects
Total
pEDM at ATR
$25.6M
$20M
$45.6M
pEDM at SEB
$14M
$39.6M
System
Experiment w/ 55% contingency
Conv. & Beamline w/ contingency
Total
pEDM at ATR
$39.5M
$29.2M
$68.7M
pEDM at SEB
$22.6M
$62.1M
EDM ring+tunnel
and beam line
EDM ring

24. Storage Ring EDM Collaboration
Aristotle University of Thessaloniki, Thessaloniki/Greece
Research Inst. for Nuclear Problems, Belarusian State University, Minsk/Belarus
Brookhaven National Laboratory, Upton, NY/USA
Budker Institute for Nuclear Physics, Novosibirsk/Russia
Royal Holloway, University of London, Egham, Surrey, UK
Cornell University, Ithaca, NY/USA
Institut für Kernphysik and Jülich Centre for Hadron Physics Forschungszentrum Jülich, Jülich/Germany
Institute of Nuclear Physics Demokritos, Athens/Greece
University and INFN Ferrara, Ferrara/Italy
Laboratori Nazionali di Frascati dell'INFN, Frascati/Italy
Joint Institute for Nuclear Research, Dubna/Russia
Indiana University, Indiana/USA
Istanbul Technical University, Istanbul/Turkey
University of Massachusetts, Amherst, Massachusetts/USA
Michigan State University, East Lansing, Minnesota/USA
Dipartimento do Fisica, Universita’ “Tor Vergata” and Sezione INFN, Rome/Italy
University of Patras, Patras/Greece
CEA, Saclay, Paris/France
KEK, High Energy Accel. Res. Organization, Tsukuba, Ibaraki , Japan
University of Virginia, Virginia/USA
>20 Institutions
>80 Collaborators

25. Technically driven pEDM timeline12 13 14 15 16 17 18 19 20 21
Two years R&D
One year final ring design
Two years ring/beam-line construction
Two years installation
One year “string test”

26. The current status
Have developed R&D plans (need $1M/year for two years) for
1) BPM magnetometers, 2) SCT tests at COSY, 3) E-field development, and 4) Polarimeter prototype
We had two successful technical reviews: Dec 2009, and March 2011.
Sent a proposal to DOE NP for a proton EDM experiment at BNL: November 2011

27. Other possible places?
COSY (Jülich/Germany); proposal for a pre-cursor experiment; we have a common R&D collaboration.
Fermilab, accumulator ring; Proposal to Fermilab? Need polarized proton source.

28. Common R&D with COSY
Slide by H. Stroeher,
Director of IKP II

29. Summary
Proton EDM physics is a must do, > order of magnitude improvement over the neutron EDM
E-field issues well understood
Working EDM lattice with long SCT and large enough acceptance (~10-29ecm/year)
Polarimeter work
Planning BPM-prototype demonstration including tests at RHIC
Old accumulator ring could house the proton EDM ring at Fermilab; BNL: new tunnel needed
Sensitivity to dark-matter axions

30. Extra slides

31. Beam parameters C.R. proton beams 0.7 GeV/c 80% polariz.;
~4×1010 protons/store
~102 m base length
Repetition period: minutes
Beam energy: ~1J
Average beam power: ~1mW
Beam emittance:
95%, norm.
Horizontal: 2 mm-mrad
Vertical: mm-mrad
(dp/p)rms~ 2×10-4
CW & CCW injections: Average emittance parameters: same to ~10% at injection.
Fermi would need to get into polarized beams physics 31

32. EDMs of different systems
Measure all three: proton, deuteron and neutron EDMs to determine CPV source
Theta_QCD:
Super-Symmetry (SUSY) model predictions:
Possible to establish axion mechanism? (Em. Mereghetti)

33. Matter-Antimatter Asymmetry in our universe
4% of our universe is made out of matter. Apparently this is too much according to SM.
The CP-violation observed within the SM can only account for ~ galaxies of the ~102 billion visible ones.
A new, much larger, source of CP-violation is needed; probably due to New Physics.

34. Main Systematic Error: particles have non-zero magnetic moments!
For the nEDM experiments a co-magnetometer or SQUIDS are used to monitor the B-field: cancellation level needed for 10-28e-cm is of order 3pG.

35. 1. Beam Position Monitors
Technology of choice: Low Tc SQUIDS, signal at Hz (10% vertical tune modulation)
R&D sequence: (First funding from US-Japan)
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

36. Physics strength comparison (Marciano)
System
Current limit [ecm]
Future goal
Neutron equivalent
Neutron
<1.6×10-26
~10-28
10-28
199Hg atom
<3×10-29
<10-29
129Xe atom
<6×10-27 ~
Deuteron nucleus
~10-29
3× ×10-31
Proton nucleus
<7×10-25
10-29 36

37. Proton EDM R&D cost: $2M
BPM development & testing over two years: $0.6M
E-field prototype development & testing: 1.8 years: $0.4M
SCT tests at COSY, 2 years: $0.4M
Polarimeter prototype, 2 years: $0.6M

38. EDMs of hadronic systems are mainly sensitive to
Theta-QCD (part of the SM)
CP-violation sources beyond the SM
A number of alternative simple systems could provide invaluable complementary information (e.g. neutron, proton, deuteron,…).
At 10-29ecm is at least an order of magnitude more sensitive than the current nEDM plans

39. BPMs The splitting depends on the vertical tune Qy
Modulating Qy would create a frequency dependent separation and a B-field at the same frequency.
Vertical position vs. time
CW beam
CCW beam

40. Magnetic field shielding issues
Reduce the N=0 Fourier component of the radial magnetic field around the ring to below 0.02nG level, when its frequency dependence is below mHz. Higher frequency (f2) B-fields need to be below (f2/f1)*0.02nG level.
For N>0, the field needs to be reduced below (N/0.1)2×(f2/f1)×0.02nG level
A combination of a passive shield ( ) and an active feedback (~104) will be used.

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

42. 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]

43. Storage Ring EDM Polarimeter Development COSY tests COSY ring:
Technical Review – 12/7/2009
Polarimeter Development
COSY tests
COSY ring:
EDDA detector:
Rings and bars to determine angles.
Use EDDA
detector UP
LEFT
DOWN
RIGHT
Azimuthal angles yield two asymmetries:
Edward J. Stephenson, IUCF 4

45. 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 103 s. Cooling/mixing during storage could prolong SCT (upgrade option?).

46. SCT Development
We have a SCT working solution (precision tracking and analytically-work in progress).
Tests with polarized deuterons and protons at COSY to benchmark software
Test runs at COSY are very encouraging.
Bonus: Electric ring with weak vertical focusing SCT is long enough for 103s storage

47. Software development Two competing requirements: accuracy, speed
Total storage ~109 revolutions, ~1.5μs/rev.
E-field complication: Kinetic energy changes with radial oscillations  horizontal focusing
Velocity/c vs. radial motion [m]

48. Software development 4th order R.K. integrator (accurate but slow) 1/R
Three different E-field
dependences:
1/R
Constant
R0.2
Consistent with analytical
estimations:
E-field radial dep.
Horizontal tune
1/R
1.275
Constant
1.625
R0.2
1.680
Radial motion [m] vs. time [s]