Electric Dipole Moments EDMs and BSM (Beyond Standard Model) physics New CP violation - Baryogenesis? How to identify origin of new CP violation Need data from multiple species Summary of experiments Short overview Sensitivities Focus on experiments potentially at Fermilab Brad Filippone PXPS12 - 6/15/12

Why EDMs? (high on some people’s lists…) “…it may be that the next exciting thing to come along will be the discovery of a neutron or atomic or electron electric dipole moment.” S. Weinberg arXiv:hepph/9211298 Dec. 2011

Why EDMs? CP Violation and the Matter/Antimatter Asymmetry in the Universe Sakharov Criteria Baryon Number Violation CP & C violation Departure from Thermal Equilibrium Standard Model CP violation is insufficient Must search for new sources of CP B-factories, LHC, Neutrinos, EDMs

Status of Electroweak Baryogenesis Appeared to be “ruled out” several years ago First order phase transition doesn’t work for Standard Model with MHiggs > 120 GeV Recent work has revived EW baryogenesis First order phase transition still viable Resonance in MSSM during phase transition with new gauge degrees of freedom M. Carena, M. Quiros, A. Riotto, I. Vilja and C. E. Wagner, Nucl. Phys. B 503, 387 (1997) Li, Profumo, Ramsey-Musolf : arXiv:0811.1987 Cirigliano, Li, Profumo, Ramsey-Musolf: JHEP 1001:002,2010 a Note: Leptogenesis is also possible

EDMs in Quantum Picture – Discrete Symmetries Charge Conjugation: Parity: Time Reversal: C P T Non-Relativistic Hamiltonian J + + - 123 123 m - + - C-even P-even T-even C-even P-odd T-odd B - + - d - + - Non-zero d violates T and CP (Field Theories generally preserve CPT) E - - +

Origin of elementary EDMs Standard Model EDMs are due to CP violation in the quark weak mixing matrix CKM (e.g. the K0/B0-system) but… e- and quark EDM’s are zero at 1 AND 2 loops Need at least three “loops” to get EDM’s (electron actually requires 4 loops!) Thus EDM’s are VERY small in standard model Neutron EDM in Standard Model is ~ 10-31 e-cm (=10-18 e-fm) g d,s,b W Experimental neutron limit: < 3 x 10-26 e-cm

How to characterize EDMs… Elementary hadronic EDMs are from qQCD (a special parameter in Quantum Chromodynamics – QCD) or from the quarks themselves qQCD Weinberg 3-gluon term CP quark color EDM (chromo-EDM) e-,quark EDM

Origin of elementary EDMs Electric dipole moments as probes of new physics Maxim Pospelov, Adam Ritz Annals Phys.318:119-169,2005 Clearly, if EDM is found, we will need multiple systems to identify the origin of new CP violation (e.g. ….

Example Calculation of EDMs System Dependence n dn ~ (3x10-16)qQCD + p dp ~ (-3x10-16)qQCD + Tl dTl ~ 585de - e(40GeV)CS 199Hg dHg ~ (0.007x10-16)qQCD - Considerable model dependence remains in above

Why do we care? It characterizes the underlying theory Origin of new CP violation influences its role in Electroweak Baryogenesis e. g. qQCD much less effective in creating matter-antimatter asymmetry since effect on vacuum is suppressed

Is there a “natural” source for new CP violation & EDMs? New physics (e.g. SuperSymmety = SUSY) often has additional CP violating phases in added couplings New phases: (fCP) should be ~ 1 (why not?) Contribution to EDMs depends on masses of new particles Gluino Chargino dn ~ 10-24 e-cm x sinjCP(1 TeV/MSUSY)2 Note: experimental limit: dn < 0.03 x 10-24 e-cm Standard Model Prediction: dn < 10-31 e-cm

Possible impacts of non-zero EDM V. Cirigliano et al., http://arxiv.org/abs/hep-ph/0603246 and private communication Must be new Physics Sharply constrains models beyond the Standard Model (especially with LHC data) May account for matter- antimatter asymmetry of the universe LHC dn= 4 x 10-28 e-cm Higgs superpartner mass dn Large Hadron Collider gauge boson superpartner mass Much more EDM theory to come: S. Gardner, K. Blum, E. Mereghetti , E. Shintani, T. Bhattacharya

Experimental EDMs Atomic/Molecular EDMs for electron EDM (paramagnetic systems = unpaired electrons) Atomic/Molecular EDMs for quark chromo-EDM (diamagnetic systems = paired electrons) Storage ring experiments for muon and proton Ultra-Cold neutron traps for neutron EDM

Experimental EDMs Present best limits come from atomic systems and the free neutron 205Tl & YbF are primarily sensitive to de 199Hg and the free neutron are primarily sensitive to Future best limits may come from Polar Molecules (ThO) Liquids (129Xe) Solid State systems (high density) Storage Rings (Muon, Deuteron, Proton, 3He) Radioactive Atoms (225Ra, 223Rn, 211Fr) New Technology for Free Neutrons PSI, ILL, SNS,FRMII,RCNP/TRIUMF

“n-EDM has killed more theories than any other single experiment” Present n-EDM limit Proposed n-EDM limit 1997 “n-EDM has killed more theories than any other single experiment”

Experimental EDM Summary Searching for New Physics beyond the Standard Model in Electric Dipole Moment Takeshi Fukuyama arXiv:1201.4252v3 [hep-ph] + p! Next Gen exps. : Improve sensitivity x10  x100

What is the precision in EDM measurement? Using Uncertainty Principle: Precise energy measurement requires long measurement time, giving But must include counting statistics Often limited by spin coherence time or particle lifetime (intermittent beam possible) E – Electric Field tm – Time for measurement m – total # of measurements N – Total # of counts/meas. Ttot – Total measurement time Sensitivity:

Often use Measurement of frequency Best neutron limit used Ramsey separated-oscillatory field technique Inject n Rotate and precess for Dt Spin rotates by wDt Measure how many nh vs. ni

Careful magnetometry is essential Careful magnetometry is essential ! (systematics, systematics, systematics) ILL neutron EDM (Baker, et al) 10,000 x EDM limit E-field reversals Raw Frequency Corrected by 199Hg Magnetometer

EDMs in the Context of Project X What experiments are possible at Fermilab? Proton EDM in storage ring (Y. Semertzidis - tomorrow) Uses infrastructure, expertise & high currents at Fermilab Radioactive atom EDM (J. Nolen & M. Dietrich -tomorrow) Isotope Separator On-Line (ISOL) production facility Neutron EDM High densities of Ultra-Cold Neutrons via spallation … (T. Chupp - tomorrow)

Storage Ring Proton EDM Radial Electric Field stores protons Long coherence time possible >103s B = vxE causes longitudinal spin to precess in horiz. plane At magic energy spin stays long. EDM causes spin to precess into vertical plane Polarimeter detects vertical spin component Counter rotating p-beams monitor systematics Vertical displacement of beams monitors false EDM (e.g. radial B-field) p = 0.7 GeV/c

Yannis Semertzidis, BNL The proton EDM ring Statistical sensitivity potentially 10x better than new neutron EDM exps. Yannis Semertzidis, BNL

What’s needed for pEDM? Infrastructure for small-scale (~ 100 m diam.) storage ring HV & proton storage ring technology High intensity low-energy proton beams

Atomic EDMs Schiff Theorem Neutral atomic system of point particles in Electric field readjusts itself to give zero E field at all charges With E-field +Q -Q E

But … Magnetic and finite size effects can break the symmetry Enhancement for de in paramagnetic atoms (unpaired electrons) Suppression for hadronic EDMs in diamagnetic atoms (paired electrons) – but “Schiff Moment” is non-zero (due to finite size of nucleus) Thus dTl ~ -10 Z3a2de ~ -585 de & |de| < 1.5 x 10-27 e-cm for 199Hg

Enhanced Atomic EDM via Octupole deformations But,but, … Enhanced Atomic EDM via Octupole deformations p Diamagnetic Paramagnetic Big enhancements possible compared to e.g. 199Hg Note: Polar Molecules also have huge enhancement factors Small applied E-field (100V/cm) leads to huge local fields (100GV/cm)

EDM in Rn Spokesmen: Timothy Chupp2 and Carl Svensson1 Sarah Nuss-Warren2, Eric Tardiff2, Kevin Coulter2, Wolfgang Lorenzon2, Timothy Chupp2 John Behr4, Matt Pearson4, Peter Jackson4, Mike Hayden3, Carl Svensson1 University of Guelph1, University of Michigan2, Simon Fraser University3, TRIUMF4 TRIUMF N2 pushes Rn into cell Neutralize and cool down Rn Rn + Rb B  E fields Analyze Rn Rn + Rb exchange g ray anisotrpy laser probing 211Rn (I=1/2; 15h) 223Rn (I=7/2; 23 m) Rate d (√day) TRIUMF 2x109 6x10-29 1x107 2x10-27 RIA 1x1010 1 3x10-29 5x108 1x10-28

An Experiment to Search for EDM of 225Ra I. Ahmad, R. J An Experiment to Search for EDM of 225Ra I. Ahmad, R. J. Holt, Zheng-Tian Lu, E. C. Schulte, Physics Division, Argonne National Laboratory Status and Outlook First atom trap of radium realized; Guest et al. PRL (2007) Search for EDM of 225Ra in 2010 Systematic improvements will follow Oven: 225Ra (+Ba) Zeeman Slower Optical dipole trap EDM probe 225Ra Nuclear Spin = ½ Electronic Spin = 0 t1/2 = 15 days Magneto-optical trap Why trap 225Ra atoms Large enhancement: EDM (Ra) / EDM (Hg) ~ 200 – 2,000 Efficient use of the rare 225Ra atoms High electric field (> 100 kV/cm) Long coherence times (~ 100 s) Negligible “v x E” systematic effect

What’s needed for radioactive atom EDM? High intensity ISOL-type facility to separate isotopes with lifetimes ~ minutes to days ~ 1 GeV proton spallation facility Thermal extraction Separator and neutralizer Medium-scale AMO type lab space Potential for > 100-1000 x radioactive atom yield

Neutron EDM Worldwide Exp UCN source cell Measurement techniques sd (10-28 e-cm) ILL CryoEDM Superfluid 4He 4He Ramsey technique for w External SQUID magnetometers Phase1 ~ 50 Phase 2 < 5 PNPI – ILL ILL turbine PNPI/Solid D2 Vac. E=0 cell for magnetometer Phase1<100 < 10 ILL Crystal Cold n Beam solid Crystal Diffraction < 100 PSI EDM Solid D2 Ramsey for w, external Cs & 3He magnetom.Possible Xe or Hg comagnetometer Phase1 ~ 50 Phase 2 < 5 SNS EDM 3He capture for w 3He comagnetometer SQUIDS & Dressed spins < 5 RCNP/TRIUMF Small vol., Xe co-mag. JPARC Under Development Munich FRMII Room Temp. , Co-mag. NIST Crystal Solid R & D ~ 5 ?

Essentially all sensitive nEDM use Ultra-Cold Neutrons (UCN) What are UCN ? Very slow neutrons (v < 8 m/s ’ l > 500 Å ) that cannot penetrate into certain materials Governed by low-energy neutron-nucleus scattering length

Higher Density UCN Sources Use non-equilibrium system (aka Superthermal) Superfluid 4He (T<1K minimizes n-reheating) (neutron) 11K (9Å ) incident neutron produces phonon & becomes UCN Solid deuterium (SD2) Gollub & Boning(83) Faster UCN production but more absorption Small re-heating if T < 6K

LANSCE SD2 UCN Source Bottle UCN valves 0.8 GeV proton beam (~20 n/proton) at 5 mA average current 1000 800 UCN Detector Bottle UCN valves 600   400 200 5 10 15 20 25 Time (sec)

New World Record UCN Density Previous record for bottled UCN = 41 UCN/cm3 (at ILL) Measurements of Ultra Cold Neutron Lifetimes in Solid Deuterium [PRL 89,272501 (2002)] Demonstration of a Solid Deuterium Source of Ultra-Cold Neutrons [Phys. Lett. B 593, 55 (2004)]

Arguaby most ambitious new n exp. is nEDM@SNS Load collection volume with polarized 3He atoms Transfer polarized 3He atoms into the measurement cell Illuminate measurement cell with polarized cold neutrons to produce polarized UCN Apply a p/2 pulse to rotate spins perpendicular to B0 Measure precession frequency Remove reduced polarization 3He atoms from measurement cell Flip E-field & Go to 1.

2 Independent Measurements Capability for using two EDM measurement techniques is built into the apparatus. Frequency measured via n-3He capture during free precession Polarized 3He as “co-magnetometer” (d3 <<< dn due to e- screening) Detect precession of 3He magnetization via SQUIDS - directly measures variation of B-field averaged over measurement cells Spin Dressing RF field can make precession of 3He and n equal (at zero E-field) to minimize sensitivity to background B-fields 2 techniques provide critical cross-check of EDM result with different systematics and risks Statistical sensitivity < 4 x 10-28 e-cm

What’s needed for nEDM? Proton spallation target coupled to cold or “ultra-cold” moderator 1 GeV proton spallation target with cold moderator & extracted, optimized cold neutron beam on SF LHe or 1 GeV proton spallation target with Ultra-Cold moderator with extracted UCN “beam” Superfluid LHe or Solid D2 Medium-size NP type lab space Proven, statistics-limited experiment Potential for x 50 higher UCN densities Beam for SNS type UCN source may be compatible with cold neutron source for n-n oscillation exp.

Summary Observation of CP-violating EDM in next decade would be NP (New Physics) Single observation is insufficient to characterize origin of CP Many experiments may be statistically limited and could benefit from Project X pEDM, Radioactive atoms (Ra, Rn, Fr), nEDM

Backup Slides

EDM Experiment at SNS

Simplified Measurement of EDM E-field 1. Inject polarized particle 2. Rotate spin by p/2 3. Flip E-field direction 4. Measure frequency shift B-field Must know B very well

New Technique for n-EDM E-field Inject polarized neutron & polarized 3He 2. Rotate both spins by 90o 3. Measure n+3He capture vs. time (note: sih>>shh) 4. Flip E-field direction B-field 3He functions as “co-magnetometer” Since 3He EDM << nEDM due to atomic e-screening

“Dressed” Spins By applying a strong non-resonant RF field, the effective precession frequencies can be modified or “dressed” For particular values of the dressing field, the neutron and 3He precession frequencies are equal

Systematic Effects in nEDM Variation of B-field Co-magnetometer cancels B-field variations Leakage currents from Electric Field These may produce heating that changes with E-field (must be less than picoAmps) effects are the largest sources of systematic error in previous ILL exp. BE = v x E g changes precession frequency Adds geometric phase when combined with B gradients

Systematic Controls in SNS experiment Highly uniform E and B fields Superconducting Magnetic Shield Two cells with opposite E-field Ability to vary influence of B0 field via “dressed spins” Study dependence on |B|, B, B-gradients & 3He density Control of central temperature Can vary 3He diffusion which changes geometric phase effect on 3He

Spallation Neutron Source (SNS) at ORNL 1 GeV proton beam with 1.4 MW on spallation target

But some molecules have HUGE EDMs! H20: d = 0.4 x 10-8 e-cm NaCl: d= 1.8 x 10-8 e-cm NH3: d = 0.3 x 10-8 e-cm If Neutron had degenerate state it would not violate T or CP u dd But NH3 EDM is not T-odd or CP-odd since Ground state is actually a superposition

Summary of Experimental Components Cold Neutron Beam Cryogenic system (77K, 4K, .35K) Polarized 3He System Must inject, transport and remove 3He With minimal polarization loss With high efficiency Magnets and Magnetic Shielding Central Detector HV, Light collection, SQUID monitors, … Technically challenging!

The nEDM Collaboration Mix of Low Temp, Atomic, Nuclear & Particle Physicists Engineers

Example of future Neutron EDM Sensitivity EDM @ ILL EDM @ SNS NUCN 1.3 x 104 4 x 105 |E| 10 kV/cm 70 kV/cm Tm 130 s 500 s m (cycles/day) 270 30 sd (e-cm)/day 3 x 10-25 4 x 10-27

Why so many nEDM?? Science remains compelling even with LHC data “PPAN was pleased to note that the consultation panel broadly confirmed the prioritisation order … The top priority projects (ATLAS, CMS, nEDM) were confirmed in this status and were graded alpha 5. “ Particle Physics, Astronomy and Nuclear Panel - UK - 2008 Superthermal UCN sources promise higher densities Exciting opportunity for new/existing facilities New = FRMII,JPARC,SNS; Existing = ILL,PSI,TRIUMF

Baryogenesis Plausibility Argument (GUTS Baryogenesis) Consider very heavy boson X (MX ~ 1019 GeV) Baryon number violation: C & CP violation Out of Thermal Equilibrium If in Equilibrium then the reverse reactions (e.g . ) will smooth out any matter/antimatter excess

EDM from qQCD This is the strong-CP problem in QCD qQCD should be naturally about ~ 1 This gives a neutron EDM of

EDM from qQCD Small qQCD does not provide any new symmetry for LQCD Elegant solution is new symmetry (Peccei-Quinn symmetry) – new term in LQCD Requires new pseudoscalar particle No Axions observed yet Extra dimensions might suppress qQCD Remains an unsolved theoretical “problem”

Status of Experiment Active R&D efforts are underway Encouraged by recent NSAC subcommittee E.g. HV in Superfluid, Magnets and shielding, 3He transport Demonstration of Electric Field strength is one remaining “Critical R&D” Construction can begin after successful demonstration of Critical R&D Cost Range: 40-50M$