DISCRETE 2010 Rome, 6-10 December 2010 + - Review of EDM experiments Yannis K. Semertzidis Brookhaven National Laboratory Motivation Neutron EDM experiments Mercury EDM 199Hg Electron EDM experiments Storage Ring EDM experiments (proton & deuteron) … Many thanks to Antonio Riotto and Josh Long for excellent talks on the subject

Physics at the Frontier, pursuing two approaches: Energy Frontier (FNAL, LHC,…) Precision Frontier (gμ-2, flavor, EDM,…) which are complementary and inter-connected. The next SM will emerge with input from both approaches.

Physics reach of magic pEDM (Marciano) Sensitivity to new contact interaction: 3000 TeV Sensitivity to SUSY-type new Physics: The proton EDM at 10-29e∙cm has a reach of >300TeV or, if new physics exists at the LHC scale, <10-7-10-5 rad CP-violating phase; an unprecedented sensitivity level. The deuteron EDM sensitivity is similar. 3

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” They knew it would violate Parity. Phys. Rev. 78 (1950)

Short History of EDM 1950’s neutron EDM experiment: a search for parity violation (before the discovery of P-violation) After P-violation was discovered it was realized EDMs require both P,T-violation 1960’s EDM searches in atomic systems 1970’s Indirect Storage Ring EDM method from the CERN muon g-2 exp. 1980’s Theory studies on systems (polar molecules) with large enhancement factors 1990’s First exp. attempts w/ polar molecules. Dedicated Storage Ring EDM method developed 2000’s Proposal for sensitive srEDM exp. approved; Magn. Opt. Traps developed, progress w/ polar mol.

In Quantum Mechanics: a non-degenerate system with Spin is defined by the spin vector + - If the particle has an EDM, its vector needs to be aligned with the spin vector, locked to its direction, i.e. it needs to choose either along or opposite but not both (non-degenerate). “CP-Violation Without Strangeness”, Khriplovich/Lamoreaux.

A Permanent EDM Violates both T & P Symmetries: + - + - T P + -

A Permanent EDM Violates both T & P Symmetries: EDM physics in degenerate systems is not important (batteries are allowed!) Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

T-Violation CP-Violation CPT Andrei Sakharov 1967: CP-Violation is one of three conditions to enable a universe containing initially equal amounts of matter and antimatter to evolve into a matter-dominated universe, which we see today…. Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 9

CP-violation was discovered at BNL in 1964

CP-violation is established The SM CP-violation is not enough to explain the apparent Baryon Asymmetry of our Universe by ~10 orders of magnitude (see excellent talk by Antonio Riotto). A new, much stronger CP-violation source is needed to explain the observed BAU.

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.

EDM Searches are Excellent Probes of Physics Beyond the SM: Most models beyond the SM predict values within the sensitivity of current or planned experiments: SUSY Multi-Higgs Left-Right Symmetric … The SM contribution is negligible… Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

The Electric Dipole Moment precesses in an Electric field The EDM vector d is along the particle spin direction + - Yannis Semertzidis, BNL

A charged particle between Electric Field plates would be lost right away. - + + Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 15

Neutron EDM Vs Year Purcell and Ramsey started a long effort “…at 3 x 10-26 e cm, it is analogous to the Earth's surface being smooth and symmetric to less than 1 µm” (John Ellis). Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 16

Spin precession at rest + - E Compare the Precession Frequencies with E-field Flipped: Caution is needed applying this equation to obtain the statistical accuracy… Yannis Semertzidis, BNL

Measuring an EDM of Neutral Particles H = -(d E + μ B) ● I/I d E B µ mI = 1/2 ω2 ω1 mI = -1/2 d = 10-28 e cm E = 200 kV/cm δw = 10-7 rad/s  ~1 turn/year 

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. (See Josh Long’s talk for application of 199Hg co-magnetometer in the nEDM.)

Important Stages in an EDM Experiment Polarize:state preparation, intensity of beams Interact with an E-field:the higher the better Analyze:high efficiency analyzer Scientific Interpretation of Result! Easier for the simpler systems Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

EDM methods (they all are sensitive to different combinations of CPV sources) Neutrons: Ultra Cold Neutrons, apply large E-field and a small B-field. Probe frequency shift with E-field flip Atomic & Molecular Systems: Probe 1st order Stark effect Storage Ring EDM for charged particles: Utilize large E-field in rest frame-Spin precesses out of plane (Probe angular distribution changes)

EDM method Advances Neutrons: advances in stray B-field effect reduction; higher UCN intensities (~106/cycle) Atomic & Molecular Systems: high effective E-fields (up to ~1-100GV/cm) Storage Ring EDM for d, p: High intensity polarized sources well developed (108/cycle); High electric fields made available; spin precession techniques in SR well studied

EDM method Weaknesses Neutrons: Intensity; High sensitivity to stray B-fields; Motional B-fields and geometrical phases Atomic & Molecular Systems: Low intensity of desired states; in some systems: physics interpretation Storage Ring EDM: sensitive to vertical E-fields or radial B-fields; some systematic errors different from g-2,…

EDM Experiments Statistics is of the essence (number of neutrons, spin coherence time,…) Systematics is close second (magnetic fields, geometrical phases,…)

nEDM experiment at ILL (Grenoble): Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

Yannis Semertzidis, BNL New UCN experiment at ILL: Expect a factor of ~100 improvement in sensitivity due to Neutrons in 0.5 K He bath ~50 more neutrons E-field: 4-6 at cryo temp. Longer coherence times Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

Neutron EDM at PSI

SNS nEDM Experiment - Vertical Section View Lower Cryostat Upper Cryostat ~6 m DR LHe Volume ~450 liters Upper Cryostat Services DR Central LHe Volume ~400 mK, ~1000 liters Reentrant Neutron Guide ABS Line 3He Injection Volume 4-layer m-metal shield Cosq magnet ABS The current value is < 3 x 10-26 e•cm (90% C.L.) Hope to obtain roughly < 8 x 10-28 e•cm with UCN in superfluid He

Strength: Some systematic errors are different from ILL and PSI experiments. Applying spin dressing techniques to equalize and further reduce the stray B-field sensitivity (see talk by Josh Long).

Yannis Semertzidis, BNL Neutron EDM Timeline ILL, n 1E-24 PSI, n SNS, n 1E-26 1E-28 EDM Limits [ecm] 1E-30 1E-32 2000 2010 2020 Future Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 30

An electron or a nucleus in a neutral atom feels a zero average E-field: + The atom is polarized and the average total E-field is zero: - + (Schiff theorem): Exceptions to the rule: a) relativistic effects b) size effects, … Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 31

Schiff Theorem: A Charged Particle at Equilibrium Feels no Force… …An electron in a neutral atom feels no force either. However, the average interaction energy is not zero because the EDM in the lab frame is velocity dependent E. Commins et al., Am. J. Phys. 75 (6) 2007

The mercury EDM experimental results published last year

The apparatus and parameter values B=22 mG V=±10 KV, E=~2 MV/m (height of cell ~1cm) SCT = 102 s

The data The drift in frequency is taken out by taking the frequency difference between the cells. Runs with micro-sparking are taken out.

Systematic errors The systematic error is ~60% of the statistical error

The results and best limits It now dominates the limits on many parameters They expect another improvement factor ~3 - 5.

Storage Ring EDM experiments (or how to create a Dirac-like particle in a storage ring) 38

A charged particle between Electric Field plates would be lost right away… - + + Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 39

…but can be kept in a storage ring for a long time Yannis Semertzidis, BNL Yannis Semertzidis, BNL 40

Yannis Semertzidis, BNL The sensitivity to EDM is optimum when the spin vector is kept aligned to the momentum vector E Momentum vector Spin vector Yannis Semertzidis, BNL Yannis Semertzidis, BNL 41

Yannis Semertzidis, BNL The spin precession relative to momentum in the plane is kept near zero. A vert. spin precession vs. time is an indication of an EDM (d) signal. E Yannis Semertzidis, BNL Yannis Semertzidis, BNL 42

Yannis Semertzidis, BNL The spin precession relative to momentum in the plane is kept near zero. A vert. spin precession vs. time is an indication of an EDM (d) signal. E E E E Yannis Semertzidis, BNL Yannis Semertzidis, BNL 43

Freezing the horizontal spin precession The spin precession is zero at “magic” momentum (0.7 GeV/c for protons, 3.1GeV/c for muons,…) The “magic” momentum concept was first used in the last muon g-2 experiment at CERN and BNL.

When P=Pmagic the spin follows the momentum No matter what the E-field value is the spin follows the momentum vector creating an ideal Dirac-like particle (g=2) Yannis Semertzidis, BNL Yannis Semertzidis, BNL 45

There is an asymmetry between E and B-fields and g-2 precession Independent of velocity! E-fields: Depends on velocity

Freezing the horizontal spin precession for the proton a=1 Freezing the horizontal spin precession for the proton a=1.79, and deuteron a=-0.143 For particles with negative anomalous magnetic moment there is no …magic. A dipole B-field is required to cancel the g-2 precession in the deuteron case

Storage Ring EDM experiments: High beam intensities (1010-1011), with high polarization (>0.8), and low emittance are currently available Large electric fields are possible (10-20MV/m) Spin coherence time ~103s are possible High efficiency, large analyzing power (~0.5) polarimeters are available for the proton and deuteron at ~1 GeV/c momentum making possible the next sensitivity level Direct access to charged particle EDMs 48

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,…).

EDMs of different systems Theta_QCD: Super-Symmetry (SUSY) model predictions:

Two different labs to host the S.R. EDM experiments BNL, USA: proton “magic” ring COSY/IKP, Germany: deuteron ring

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 10-25-10-26 129Xe atom <6×10-27 ~10-29-10-31 10-25-10-27 Deuteron nucleus ~10-29 3×10-29- 5×10-31 Proton nucleus <7×10-25 10-29 53

Yannis Semertzidis, BNL Hadronic EDM Timeline ILL, n 1E-24 PSI, n SNS, n 1E-26 BNL, p COSY, d 1E-28 EDM Limits [ecm] 199Hg 1E-30 129Xe 129Xe, Rn, Ra 1E-32 2000 2010 2020 Future Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 54

Electron EDM experiments Current limit: 1.6×10-27 (90%), from Tl (paramagnetic) atom Future: Paramagnetic atoms: Fr, Cs Polar molecules: YbF, PbO, ThO, PbF, HBr, BaF, HgF, ThO, … Solids: GGG, … unpaired electron －　 + paramagnetic atom diamagnetic internal electric field　 10～100 GV/cm paramagnetic molecule (radical) Fr Sr

Yannis Semertzidis, BNL Electron EDM Timeline Tl, e- 1E-24 Polar mol. 1E-26 1E-28 EDM Limits [ecm] 1E-30 1E-32 2000 2010 2020 Future Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002 56

Sensitivity to Rule on Several New Models Baryogenises Electroweak GUT SUSY Gray: Neutron Red: Electron n current e current n target p, d target e target e-cm (Adopted from J. Long’s slide) J.M.Pendlebury and E.A. Hinds, NIMA 440 (2000) 471

Summary The 199Hg Exp. sets many of the current limits Better sensitivity is expected within 5-10 years for 199Hg, 129Xe, Fr, Rn, Ra, YbF,… and neutron The proton EDM experiment for 10-29e-cm has been recently approved at BNL and preparing a proposal for DOE-NP. Results >2015. By the end of the decade we could have a number of new improved results and either we are discovering or setting severe constraints on BSM CP-Violation. If found, they will help explain the large BAU mystery. In any case we’ll have a lot of fun and learn a great deal!

Brookhaven National Laboratory Home of the only polarized proton collider in the world up to 500 GeV on 500 GeV Long experience with polarized sources: a few times 1011 protons with ≥80% polarization Our needed proton beam parameters are readily available Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

Clock-wise (CW) & Counter-clock-wise (CCW) storage 60

Experimental needs Two Proton bunches 0.7 GeV/c 90% polariz.; <100m base length Rep. rate: 103s Beam energy: ~1J Average beam power: ~1mW Beam emittance: 95%, unorm. Horizontal: 3mm-mrad Vertical: 10mm-mrad (dp/p)rms~ 2.5×10-4 CW & CCW injections: Average beam parameters: same to ~10% 61

E-field plate module: The (26) FNAL Tevatron ES-separators would do Beam position 0.4 m 3 m Vertical plates are placed everywhere around the ring to minimize vertical electric/radial B- fields from image charges

pEDM polarimeter principle: probing the proton spin components as a function of storage time Micro-Megas TPC detector and/or MRPC “defining aperture” polarimeter target extraction adding white noise to slowly increase the beam phase space carries EDM signal increases slowly with time carries in-plane precession signal

Is the polarimeter analyzing power good at Pmagic? YES! Analyzing power can be further optimized Yannis Semertzidis, BNL

Certain (main) systematic errors easier to handle if CW & CCW is done at the same time (Coincident BeamS: CBS) In a ring with Electric field bending it is possible to store protons CW & CCW at the same time in the same place

OSCILLATING VERTICAL FOCUSING OSCILLATES SIGNAL AT SAME FREQUENCY

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]

Proton Statistical Error (230MeV): p : 103s Polarization Lifetime (Spin Coherence Time) A : 0.6 Left/right asymmetry observed by the polarimeter P : 0.8 Beam polarization Nc : 21010p/cycle Total number of stored particles per cycle TTot: 107s Total running time per year f : 0.5% Useful event rate fraction (efficiency for EDM) ER : 17 MV/m Radial electric field strength (65% azim. cov.) Yannis Semertzidis, BNL 68

Sensitivity to Rule on Several New Models Baryogenises Electroweak GUT SUSY Gray: Neutron Red: Electron p current n current e current n target p,d target e target e-cm J.M.Pendlebury and E.A. Hinds, NIMA 440 (2000) 471

Technically driven pEDM Timeline 07 08 09 10 11 12 13 14 15 16 17 Spring 2008, Proposal to the BNL PAC Fall 2009 Conceptual Technical Review at BNL December 2009, the pEDM experiment is approved 2010-2013 R&D phase; ring design Fall 2012, Finish R&D studies: a) Develop BPMs, 10 nm, 1 Hz BW resolution, <1pm syst. b) spin/beam dynamics related systematic errors. c) Polarimeter detector development and prepare for testing d) Finalize E-field strength to use e) Establish Spin Coherence Time, study systematic errors, optimize lattice FY 2013, start ring construction (two years) 70

From the September 2008 run at COSY Polarimeter team Resonance crossing (full spin flip) Vector asymmetry V+ T− Unp V− T+ Slowly extracting the beam while monitoring its polarization as a function of time

EDMs: New CPV? sinCP ~ 1 -> M > 5000 GeV SM “background” well below new CPV expectations New expts: 102 to 103 more sensitive CPV needed for BAU? 3.1 x 10-29 Mass Scale Sensitivity sinCP ~ 1 -> M > 5000 GeV M < 500 GeV -> sinCP < 10-2

Main polarimeter systematic errors Polarimeter team Main polarimeter systematic errors

Gas cluster ion beam surface treatment

AGS Complex at BNL AGS m g-2 experiment NSRL Linac TTB pEDM @ 17 MV/m pEDM Ring 30.8m Linac Booster AGS 100 m TTB C-AD Admin

Storage Ring EDM Polarimeter Development Polarimeter Technical Review – 12/7/2009 Polarimeter Development Polarimeter (Half) Polarimeter in the ring: Absorber to remove low analyzing power particles. (Detector choice can also give discrimination.) Quadrupoles here are larger aperture for clearance. 5° to 20° acceptance Equal rate readout pads One target is shown. We want a target available from at least the left, right, up and down directions. cm Generic detector: (?) Multi-resistive plate chamber (?) Micro-megas (?) Gas electron multiplier (?) …other Rate = 800 /s/pad In one store: Edward J. Stephenson, IUCF 15

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

Storage Ring EDM Polarimeter Development Target Concept Technical Review – 12/7/2009 Polarimeter Development Target Concept Target solution found at COSY: expanded vertical phase space beam core end view White noise applied to electric field plates. maximum allowed at COSY 15 mm Do enough particles penetrate far enough into the front face to travel most of the way through the target? This requires a comparison of the efficiency with model values. Edward J. Stephenson, IUCF 5

Polarimeter rates: Beam intensity with 2×1010 pol. protons/ ~103s and a detection efficiency of 1%  200KHz for ~3000cm2 area, or ~100Hz/cm2 on average but much higher at small radius. Design: ~1KHz/pad. 70 cm

Applying Micro-Megas TPC Differentiate between protons and deuterons Have a pointing accuracy of 0.5mrad/event Yannis Semertzidis, BNL

Electric Dipole Moment EDM T + + T violation ~ CP violation under CPT invariance Electric Dipole Moment ー ー Standard Model Lowest order where EDM appears Estimation ~ 10-37 e・cm Small SM background EDM～sensitive to the phenomena beyond the standard model Super Symmetry

Francium EDM Fr Tl Xe Cs Rb Small e-EDM ~ magnified in the heavy paramagnetic atoms Fr Rb Xe Cs Tl Fr Enhancement factor Francium : Heaviest alkali element e-EDM enhancement ~ largest ~ 1150 Atomic structure ~ simple Radioactive atom ~ τ~ 3 min.

EDM search with laser cooled atoms 1 nK 1 mK 1 K 1000 K Room temp. liq. 4He liq. 3He Laser cooling Evaporative cooling Temp. BEC FD Trap laser cooled Fr atoms with ~uK → long coherence time, realize the accurate measurement Laser cooled and trapped atoms Atomic beam 210Fr Tl（world record） 1150 K: enhancement 585 ~102 sec t： coherence time ~10-3 sec > 10-29 EDM (e・cm) ~10-27 Laser Magneto-Optical Trap Radioactive atom 210Fr with largest enhancement of e-EDM Produce the 210Fr using nuclear fusion reaction Long coherence time ～ laser cooled and trapped 210Fr atoms Achieve the high accuracy measurement

e-EDM experiment with atom in the world EDM of stable alkaline atoms Cesium Fountain EDM experiment (Harvey Gould et al., LBNL, California, USA) Projected accuracy de~1×10-29 e cm EDM experiment of Cs and Rb in 1-D Optical Lattice (David Weiss et al., Penn. State Univ., USA) Projected accuracy de~5×10-30 e cm Cesium EDM Experiment using Optical Dipole Force Traps (Heinzen et al., University of Texas, Austin, USA) Projected accuracy de~10-29 e cm Cesium EDM Experiment using Optical Lattice (K. Honda, Tokyo Institute of Technology, Tokyo, Japan) Many activities in the world ….

Possibility of ultracold polar molecules e-EDM sensitivity unpaired electron －　 + paramagnetic atom diamagnetic internal electric field　 10～100 GV/cm paramagnetic molecule (radical) Fr Sr P : polarization of the system Eeff : internal electric field t : interaction time N : number of molecules T : integration time Preparation method of ultracold molecules ・Direct laser cooling of molecules is difficult.　 （interaction time of molecular beam t is short, ～1 ms or ms） ・We laser cool and trap Fr atoms and Sr atoms, then associate molecules from Fr and Sr mixture through magnetically tunable Feshbach resonance/ photoassociation technique. 　　　　 longer interaction time t ～ 1 s in trapped ultracold polar molecules ～10-29 e cm @ 1 day integration if Eeff = 10 GV/ cm, N = 104

Coil and Shield Nesting Inner-Dressing & Spin-Flip Coil 50K Shield Outer Dressing Coil 4K Shield Superconducting Lead Shield Ferromagnetic Shield B0 cosθ Magnet

EDMs: What We May Learn Present n-EDM limit Proposed n-EDM limit Slide by M.J. Ramsey-Musolf EDMs: What We May Learn Present n-EDM limit Proposed n-EDM limit Refined theory ? New theory ? Leptogenesis ? Matter-Antimatter Asymmetry in the Universe ? “n-EDM has killed more theories than any other single experiment”

Yannis Semertzidis, BNL 3 Deuteron EDM, UoR, 18 April, 2006 Yannis Semertzidis, BNL

Ramsey’s method of separated fields Yannis Semertzidis, BNL Yannis Semertzidis, BNL. ICHEP02, 31 July 2002

Matter-Antimatter Asymmetry in our universe Pie chart of energy share of our universe 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 mass equivalent to ~101-102 galaxies compared to ~102 billion visible ones. A new, much larger, source of CP-violation is needed; probably due to New Physics.

The great mystery in our universe: matter dominance over anti-matter