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Electric dipole moment searches Peter Fierlinger.

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Presentation on theme: "Electric dipole moment searches Peter Fierlinger."— Presentation transcript:

1 Electric dipole moment searches Peter Fierlinger

2 Outline P. Fierlinger – MeNu2013 Motivation Different systems to search for electric dipole moments (EDMs) Examples

3 Electric dipole moment + - Magnetic moment Purcell and Ramsey, PR78(1950)807 A non-zero particle EDM violates P … and T (time reversal symmetry) … assuming CPT conservation, also CP EDM P. Fierlinger – MeNu2013

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

5 Neutron EDM d n  ecm (d e < ecm) -d n much more difficult to calculate, but still small Neutron EDM and the SM Khriplovich Zhitnitsky (1986), McKellar et al., (1987) E.g. Pospelov, Ritz, Ann. Phys. 318(2005)119 CP violation from CKMStrong Interaction Strong CP problem CP-odd term in Lagrangian: P. Fierlinger – MeNu2013 T. Mannel, N. Uraltsev, Phys.Rev. D85 (2012) M. Pospelov, et al., Sov. J. Nucl. Phys. 53, 638 (1991)

6 Baryon asymmetry JETP Lett. 5 (1967) 24 Observed: n B / n γ ~ 6 x (BBN, CMB) Expected: n B / n γ ~ MUCH smaller ‚Ingredients‘ to model baryogenesis: Sakharov criteria e.g. astro-ph/ Beyond-SM physics usually requires large EDMs - EDMs and Baryogenesis via Leptogenesis? - Also other options w/o new CP violation possible (Kostelecky, CPT) - SUSY: small CPV phases, heavy masses, cancellations? - What do we learn from an EDM? Different measurements are needed! Remarks: e.g. Cirigliano, Profumo, Ramsey-Musolf JHEP 0607:002 (2006) P. Fierlinger – MeNu2013

7 Physics behind EDMs Schiff-Moment  Z³ dede Diamagnetic atoms Paramagnetic atoms, polar / charged molecules dqdq dqdq ~ C S,P, T C qe C qq g  NN  Ions Schiff-Moment  Z² dd dd See e.g. Pospelov, Ritz, Ann. Phys. 318(2005)119 Leptons Neutron, proton P. Fierlinger – MeNu2013

8 Atom EDM Paramagnetic atoms ~ electron EDM Relativistic effects Schiff moment: Non-perfect cancellation of E ext in atomic shell Diamagnetic atoms ~ nuclear EDM Finite size of nucleus violates Schiff‘s theorem E ext L. Schiff, Phys. Rev. 132, 2194 (1963) Large enhancements also with deformed nuclei (Ra, Rn, also Fr, Ac, Pa) Sandars, 1968 Schiff 1963; Sandars, 1968; Feinberg 1977; P. Fierlinger – MeNu2013

9 Atomic effects Contributions to atomic EDMs: -13 (model-dependent) parameters TeV-scale CP odd physics, nucleon level, nucleus-level -Only 8 types of experiments See also J. Engel, M. J. Ramsey-Musolf, U. van Kolck, Prog. Part. Nucl. Phys. 71, 21 (2013) g π0 g π1 P. Fierlinger – MeNu2013 Illustration: T. Chupp et al., to be published *)

10 Measuring the neutron EDM (RAL/SUSSEX/ILL experiment) B0 B0 Ultra-cold neutrons (UCN) trapped at 300 K in vacuum E kin < 250 neV > 50 nm T ~mK Storage ~ 10 2 s P. Fierlinger – MeNu2013 ~ 0.5 m

11 Ramsey‘s method Polarization  1 -  L („detuning“) EDM changes frequency: Particle beam or trapped particles P. Fierlinger – MeNu2013 E

12 Clock-comparison experiment - Neutrons and 199 Hg stored in the same chamber - Gravity changes center of mass! Physical Review Letters 97 (2006) Requirement: 199 Hg-EDM must be small: (btw., this also limits other parameters, e.g C S, C T...): d n < 2.9 x e cm B 0 up B 0 down Analysis using the gradient: Illustration (2008 data) Applied Gradient Frequency ratio B =1  T ( + small vertical gradient) P. Fierlinger – MeNu2013 Hg-EDM: W. C. Griffith et al., PRL 102, (2012) d Hg < 3.1 x e cm

13 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 Cold beam Turbine sD2 4He B and E field ring Electrostatic ring Goal (x ecm) 1.~ 50; 2. < 5 < 100 < 5 < ~ 100; 2. < ~ 50; 2. < 5 < 5 < R&D; ; Comments Larger revisions to come Diffraction in crystal: large E Adjustable UCN velocity Special UCN handling R&D E = 0 reference cell Phase 1 takes data Sophisticated technology Phase II at TRIUMF Stepwise improvements Completely novel technology Neutron and proton experiments P. Fierlinger – MeNu2013

14 14 ‚Current generation‘ improvements UCN density measured in a 25l volume extrapolated to t=0 at PSI area West ~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 PSI (taken from B. Lauss, K. Kirch), for actual numbers see PSI EDM talk PNPI/ILL (taken from A. Serebrov, 2013): UCN density 3-4 ucn/cm 3 (MAM position) Electric field 10 kV/cm T(cycle) = 65 s...new electric field 20 kV/cm δD edm ~ 5∙ e∙cm/day δD edm ~ 2.5∙ e∙cm/day ~ 2014: EDM position at PF2 1∙ e∙cm/100 days P. Fierlinger – MeNu2013

15 ‚Next generation‘ Pendlebury et al., Phys. Rev. A 70, (2004) Further: P. G. Harris et al., Phys. Rev. A 73, (2006), also: G. Pignol, arXiv: (2012). Most critical for next generation experiments: ‚geometric phases‘ Magnetic field requirements for ecm – level accuracy: ~ fT field drift error, ~ < 0.3 nT/m avg. gradients d f ~ ecm ( 199 Hg geom. phase) d n ~ ecm (UCN geom. phase) Example: Dipole fields in EDM chambers 20 pT in 3 cm ~ 5 x error budget! 200 pT pp demagnetized: 20 pT pp SQUID measurements of Sussex EDM PTB Berlin ~ 0.3 m Statistics: 10 3 UCN/cm 3 ~ 1 year P. Fierlinger – MeNu2013

16 Superthermal solid D 2 or superfluid 4 He-II SD 2 : Molceular excitations used to cool neutrons to zero energy - similar: ILL, LANL, Mainz, NCSU, PNPI, PSI, TUM … New sources of UCN Goal of most sources: 10³ UCN /cm³ in experiment 4 He: ILL, KEK, SNS, TRIUMF, … P. Fierlinger – MeNu2013

17 The smallest extended size field and gradient on earth -< 100 pT/m gradient in 0.5 m 3 -At FRM-II EDM setup: fields designed and measured - this technology is ready and available! x [m] y [-0.5 m – 0.5 m] z = 0.5 m z = 0 m (center) z = m [nT] SQUID offset in z not corrected Magnetic fields P. Fierlinger – MeNu2013

18 Next generation neutron EDMs E.g. at FRM-II (reactor): -‚Conventional‘, double chamber -UCN velocity tuning -Cs, 3 He, 199 Hg, 129 Xe (co)magnetometers -Ready for UCN in 1 year E.g. at SNS (spallation): -Cryogenic, double chamber -Neutron detection via spin dependent 3 He absorption and scintillation - 3 He co-magnetometry P. Fierlinger – MeNu2013 In the future... again nEDM with a cold beam? Pulse structure and strong peak flux: -Cold-beam-EDM at long-pulse-neutron source (ESS) could be competitive? (Piegsa, PRC, soon...) -Re-accelerated polarized UCN with pulse-structure? (PF, in prep.)

19 Next generation nucleon EDMs Proton, deuteron,... EDM Charged particle EDM searches require the development of a new class of high-precision storage rings Projected sensitivity ~ ecm: … tests  to < ! Currently 2 approaches: -JEDI collab.: starting with COSY ring, development in stages E, B fields -BNL: completely electrostatic, new design all-electric ring Requirements: -Electric field gradients 17 MV/m (possible) -Spin coherence times > 1000 s (200s demonstrated at Jülich) -Continuous polarimetry < 1 ppm error (demonstrated at Jülich) -Spin tracking simulations of 10 9 particles over 1000 s P. Fierlinger – MeNu2013

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

21 Octupole deformations: 225 Ra Ra Oven: Zeeman Slower Optical dipole trap EDM probe Why trap 225 Ra atoms: efficient use of the rare 225 Ra atoms high electric field (> 100 kV/cm) long coherence times ~ 100 s negligible “v x E” effect -Goal ~ ecm -Main issue: statistics (Project X?) Nuclear Spin = ½ t 1/2 = 15 days Magneto-optical trap Schiff moment of 225 Ra, Dobaczewski & Engel, PRL (2005) Enhancement factors: EDM ( 225 Ra) / EDM ( 199 Hg) ~ 10 3 Figures: Z.-T. Lu MOT: Guest et al., PRL (2007) Dipole trap: Trimble et al. (2010) P. Fierlinger – MeNu2013

22 Lepton EDM measurements P. Fierlinger – MeNu2013 Best limits: Mainly paramagnetic systems and polar molecules -Cs, Tl, YbF: d e < ecm (E. Hinds et al.) -Soon: ThO – currently taking data -Molecules, molecular ions, solids: PbO, PbF, HBr, BaF, HgF, GGG, Gd 2 Ga 5 O 12 etc. -d GGG ~ < ecm -d  < (90%) ecm from g-2 -d  < (90%) ecm from Z  Diamagnetic atoms also contribute to such limits! Shapiro, Usp. Fiz. Nauk., (1968) Tl, YbF limits together, courtesy T. Chupp (2013)

23 The ACME experiment P. Fierlinger – MeNu2013 -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 Figures: J. Doyle Status: taking data with ecm /  day

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 ecm atoms ~ < ecm (ThO, 199 Hg, 129 Xe) 6 years: nEDM ~ few ecm atoms - hard to predict... Note: my nEDM time estimate stayed constant since 2009 P. Fierlinger – MeNu2013

25 New concepts? Re-acceleration of UCN A possibility to produce extremely high brightness ‚cold‘ neutron beams: concept demonstrated (Rauch et al.) Next step: Perfect polarization (PF et al.) S. Mayer et al., NIM A 608 (2009) 434–439 Again: nEDM measured with a cold beam? Beam-EDM at long-pulse-neutron source could be competitive (Piegsa et al., to be published soon) Why not use a combination: perfectly polarized, re- accelerated high brightness beam with extremely well known time structure for in-beam EDM?

26 Supersymmetry MSSM for M = 1 TeV, tan  =3 More sources of CP violation ~ EDMs at 1 loop level Pospelov, Ritz, Ann. Phys. 318(2005)119 Hg EDM ~ exp. Limit! MSSM example: Consequences - small phases: problem for baryogenesis - cancellations: requires tuning - heavy masses Boson coupling Higgsino mass phase P. Fierlinger – MeNu2013


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