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Electric dipole moment searches

Electric dipole moment searches

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Electric dipole moment searches

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  1. Electricdipolemomentsearches Peter Fierlinger

  2. Outline Motivation Different systemstosearchforelectricdipolemoments (EDMs) Examples P. Fierlinger – MeNu2013

  3. Electricdipolemoment Magneticmoment A non-zeroparticle EDM violates P … and T (time reversal symmetry) … assuming CPT conservation, also CP - Purcell and Ramsey, PR78(1950)807 EDM + P. Fierlinger – MeNu2013

  4. History L-R symmetric n p MSSM ~1 Ramsey & Purcell (1950) n n+Hg e- Xe n Multi- Higgs e-(Tl) EDM limits [e.cm] n Hg `01 Hg `09 MSSM ~/ Atoms e- SM neutron SM electron

  5. Neutron EDM andthe SM CP violationfrom CKM Strong Interaction CP-odd term in Lagrangian: KhriplovichZhitnitsky (1986), McKellar et al., (1987) E.g. Pospelov, Ritz, Ann. Phys. 318(2005)119 M. Pospelov, et al., Sov. J. Nucl. Phys. 53, 638 (1991) • Neutron EDM dn 10-32ecm(de < 10-38ecm) • dn much more difficult to calculate, but still small Strong CP problem T. Mannel, N. Uraltsev, Phys.Rev. D85 (2012) 096002 P. Fierlinger – MeNu2013

  6. Baryon asymmetry Observed: nB / nγ ~ 6x 10-10 (BBN, CMB) Expected: nB / nγ~ MUCH smaller e.g. astro-ph/0603451 ‚Ingredients‘ tomodelbaryogenesis: Sakharov criteria JETP Lett. 5 (1967) 24 Remarks: e.g. Cirigliano, Profumo, Ramsey-Musolf JHEP 0607:002 (2006) • Beyond-SM physicsusuallyrequires large EDMs • EDMs andBaryogenesis via Leptogenesis? • Also otheroptions w/o new CP violationpossible(Kostelecky, CPT) • SUSY: small CPV phases, heavy masses, cancellations? • What do welearnfrom an EDM? • Different measurementsareneeded! P. Fierlinger – MeNu2013

  7. Physicsbehind EDMs de d d dq  Cqe Cqq dq gNN CS,P, T Neutron, proton ~ Leptons See e.g. Pospelov, Ritz, Ann. Phys. 318(2005)119 Schiff-Moment  Z² Ions Schiff-Moment  Z³ Diamagnetic atoms Paramagneticatoms, polar / chargedmolecules P. Fierlinger – MeNu2013

  8. Atom EDM Schiff moment: Non-perfectcancellation of Eext in atomicshell Paramagneticatoms ~ electron EDM Relativisticeffects L. Schiff, Phys. Rev. 132, 2194 (1963) Sandars, 1968 Diamagneticatoms ~ nuclear EDM Finite sizeofnucleusviolatesSchiff‘stheorem Eext Schiff 1963; Sandars, 1968; Feinberg 1977; ... - 2010 Large enhancements also withdeformednuclei (Ra, Rn, also Fr, Ac, Pa) P. Fierlinger – MeNu2013

  9. Atomiceffects Contributionstoatomic EDMs: • 13 (model-dependent) parameters • TeV-scale CP oddphysics, nucleonlevel, nucleus-level • Only 8 types of experiments Illustration: T. Chuppet al., to be published *) See also J. Engel, M. J. Ramsey-Musolf, U. van Kolck, Prog. Part. Nucl. Phys. 71, 21 (2013) gπ1 gπ0 P. Fierlinger – MeNu2013

  10. Measuring the neutron EDM (RAL/SUSSEX/ILL experiment) Ultra-coldneutrons (UCN) trappedat 300 K in vacuum Ekin < 250 neV  > 50 nm T ~mK Storage ~ 102 s B0 ~ 0.5 m P. Fierlinger – MeNu2013

  11. Ramsey‘smethod Particle beam ortrappedparticles Polarization E 1-L („detuning“) EDM changesfrequency: P. Fierlinger – MeNu2013

  12. Clock-comparisonexperiment - Neutrons and199Hg stored in the same chamber - Gravity changes center of mass! B =1 T ( + smallverticalgradient) Physical Review Letters  97 (2006) 131801. Illustration (2008 data) Analysis using the gradient: B0 down B0up dn < 2.9 x 10-26 e cm Applied Gradient Requirement: 199Hg-EDM must besmall: (btw., this also limitsotherparameters, e.g CS, CT...): dHg < 3.1 x 10-29e cm Frequencyratio Hg-EDM: W. C. Griffith et al., PRL 102, 101601 (2012) P. Fierlinger – MeNu2013

  13. Neutron andprotonexperiments nEDM Cryo EDM ILL Crystal EDM FRM-II EDM JPARC NIST Crystal PNPI/ILL PSI EDM SNS EDM TRIUMF/RNPC pEDM Jülich BNL Method 4He Solid sD2 sD2 Cold beam Turbine sD2 4He 4He B and E field ring Electrostatic ring Goal (x10-28ecm) ~ 50; 2. < 5 < 100 < 5 < 10 < 10 1. ~ 100; 2. < 10 1. ~ 50; 2. < 5 < 5 < 10 1. R&D; 2. 10-24; 3. 10-29 10-29 Comments Larger revisionstocome Diffraction in crystal: large E AdjustableUCN velocity Special UCN handling R&D E = 0 referencecell Phase 1 takesdata Sophisticatedtechnology Phase II at TRIUMF Stepwiseimprovements Completelynoveltechnology P. Fierlinger – MeNu2013

  14. ‚Currentgeneration‘ improvements PSI (taken from B. Lauss, K. Kirch), for actual numbers see PSI EDM talk PNPI/ILL (taken from A. Serebrov, 2013): • UCN density measured in a 25l volume • extrapolated to t=0 • at PSI area West-1 • 2010 ~0.15 UCN/cm3 • 2011 ~18 UCN/cm3 • 2012 ~23 UCN/cm3 • correct for detector foil transmission • status (4/2013) >33 UCN/cm3 in storage experiment (-> this is an extrapolation) • < 2 UCN/cm3 in EDM experiment UCN density 3-4 ucn/cm3 (MAM position)Electric field 10 kV/cm T(cycle) = 65 s ...new electric field 20 kV/cm δDedm ~ 5∙10-25 e∙cm/day ~ 2014: EDM position at PF2 1∙10-26 e∙cm/100 days δDedm ~ 2.5∙10-25 e∙cm/day 14 P. Fierlinger – MeNu2013

  15. ‚Next generation‘ Most criticalfornextgenerationexperiments: ‚geometricphases‘ Example: Dipole fields in EDM chambers 20 pT in 3 cm ~ 5 x errorbudget! SQUID measurements of Sussex EDM electrodes @ PTB Berlin Pendlebury et al., Phys. Rev. A 70, 032102 (2004) Magneticfieldrequirements for 10-28 ecm – levelaccuracy: ~ fTfielddrifterror, ~ < 0.3 nT/m avg. gradients df ~ 4.10-27 ecm (199Hg geom. phase) dn~ 1-2.10-28ecm(UCN geom. phase) ~ 0.3 m demagnetized: 20 pT pp 200 pT pp Statistics: 103UCN/cm3 ~ 1 year Further: P. G. Harris et al., Phys. Rev. A 73, 014101 (2006), also: G. Pignol, arXiv:1201.0699 (2012). P. Fierlinger – MeNu2013

  16. New sourcesof UCN Superthermal solid D2or superfluid 4He-II SD2: Molceularexcitationsusedto cool neutronstozeroenergy - similar: ILL,LANL, Mainz, NCSU, PNPI, PSI, TUM … 4He:ILL, KEK, SNS, TRIUMF, … Goal of mostsources: 10³ UCN /cm³ in experiment P. Fierlinger – MeNu2013

  17. Magneticfields • The smallest extended size • field and gradient on earth • < 100 pT/m gradient in 0.5 m3 • At FRM-II EDM setup: fields designed and measured -this technology is ready and available! z = - 0.5 m z = 0 m (center) z = 0.5 m x [m] [nT] SQUID offset in z not corrected y [-0.5 m – 0.5 m] P. Fierlinger – MeNu2013

  18. Next generationneutron EDMs • E.g. at FRM-II (reactor): • ‚Conventional‘, double chamber • UCN velocitytuning • Cs, 3He, 199Hg, 129Xe (co)magnetometers • Readyfor UCN in 1 year • E.g. at SNS (spallation): • Cryogenic, double chamber • Neutron detection via spindependent • 3He absorptionandscintillation • 3He co-magnetometry • In the future... againnEDMwith a cold beam? • Pulse structureand strong peakflux: • Cold-beam-EDM atlong-pulse-neutron source (ESS) couldbecompetitive? (Piegsa, PRC, soon...) • Re-acceleratedpolarized UCN with pulse-structure? (PF, in prep.) P. Fierlinger – MeNu2013

  19. Next generationnucleon EDMs • Proton, deuteron, ... EDM • Chargedparticle EDM searchesrequire the development of a newclass of high-precisionstorage rings • Projectedsensitivity ~ 10-29ecm: … tests to < 10-13! • Currently 2 approaches: • JEDI collab.: startingwith COSY ring, development in stages • E, B fields • BNL: completelyelectrostatic, new design • all-electricring • Requirements: • Electricfieldgradients 17 MV/m (possible) • Spin coherencetimes > 1000 s (200s demonstratedat Jülich) • Continuouspolarimetry < 1 ppm error(demonstratedat Jülich) • Spin trackingsimulations of 109particlesover 1000 s P. Fierlinger – MeNu2013

  20. Proton EDM in ‚magic‘ ring - Frozen horizontal spinprecession: p || s - EDM turns s out of plane P, S aligned V. Bargmann, L. Michel and V. L. Telegdi, Phys. Rev. Lett. 2 (1959) 435. • Magic ring: • - Purelyelectric ring onlyfor G > 0 • - E and B ring forother isotopes Electrostatic ring proposal at BNL Figures: H. Stroeher P. Fierlinger – MeNu2013

  21. Ra Oven: Zeeman Slower EDM probe Optical dipole trap Octupoledeformations: 225Ra Enhancement factors: EDM (225Ra) / EDM (199Hg) ~ 103 Why trap 225Ra atoms: efficient use of the rare 225Ra atoms high electric field (> 100 kV/cm) long coherence times ~ 100 s negligible “v x E” effect Nuclear Spin = ½ t1/2= 15 days Schiff moment of 225Ra, Dobaczewski & Engel, PRL (2005) Magneto-optical trap • Goal ~ 10-28ecm • Main issue: statistics • (Project X?) MOT: Guest et al., PRL (2007) Dipole trap: Trimble et al. (2010) Figures: Z.-T. Lu P. Fierlinger – MeNu2013

  22. Lepton EDM measurements • Best limits: • Mainlyparamagneticsystemsand polar molecules • Cs, Tl, YbF: de < 1.05.10-27ecm (E. Hinds et al.) • Soon: ThO – currentlytakingdata • Molecules, molecularions, solids: PbO, PbF, HBr, BaF, HgF, GGG, Gd2Ga5O12 etc. • dGGG ~ < 10-24ecm • d < 1.8 . 10-19 (90%) ecmfromg-2 • d < 1.7 . 10-17 (90%) ecmfromZ • Diamagneticatoms also • contributeto such limits! Shapiro, Usp. Fiz. Nauk., 95 145 (1968) Tl, YbF limits together, courtesy T. Chupp (2013) P. Fierlinger – MeNu2013

  23. The ACME experiment • ThO molecules: • 100 GV/cm internal electric field due to level structure, • polarizable with very small lab-field • Small magnetic moment, therefore less sensitive to B-field quality • High Z: enhancement • Well understood system • Lasers to select states • High statistics: • strong cold beam Status: takingdatawith 10-28ecm /day Figures: J. Doyle P. Fierlinger – MeNu2013

  24. Summary New EDM experiments are highly sensitive probes for new physics Several experiments must be performed to understand the underlying physics. (Then, also a measured limit may be a discovery...) Experimental techniques span from table top AMO - solid state - low temperature – accelerators - neutron physics Next generation precision within next 2 years: nEDM ~ few 10-27ecm atoms ~ < 1.10-29ecm (ThO, 199Hg, 129Xe) 6 years: nEDM ~ few 10-28ecm atoms - hard to predict ... Note: my nEDM time estimate stayed constant since 2009 P. Fierlinger – MeNu2013

  25. New concepts? Re-acceleration of UCN Apossibilitytoproduceextremely high brightness ‚cold‘ neutronbeams: conceptdemonstrated(Rauch et al.) Next step: Perfectpolarization (PF et al.) S. Mayer et al., NIM A 608 (2009) 434–439 Again: nEDMmeasuredwith a cold beam? Beam-EDM atlong-pulse-neutron sourcecouldbecompetitive(Piegsa et al., tobepublishedsoon) Why not use a combination: perfectlypolarized, re-accelerated high brightness beam withextremelywellknown time structurefor in-beam EDM?

  26. Supersymmetry More sourcesof CP violation ~ EDMs at 1 looplevel MSSM example: MSSM for M = 1 TeV, tan =3 Hg EDM ~ exp. Limit! Bosoncoupling Pospelov, Ritz, Ann. Phys. 318(2005)119 • Consequences • smallphases: • problemforbaryogenesis • cancellations: requirestuning • heavy masses Higgsinomassphase P. Fierlinger – MeNu2013