The search for permanent electric dipole moments Klaus Kirch Paul Scherrer Institut and ETH Zürich

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Kimberly Johns
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1 The search for permanent electric dipole moments Klaus Kirch Paul Scherrer Institut and ETH Zürich + _ 1

2 The search for permanent electric dipole moments Klaus Kirch Paul Scherrer Institut and ETH Zürich 2

3 The search for permanent electric dipole moments Klaus Kirch Paul Scherrer Institut and ETH Zürich 3

4 Nature has probably violated CP when generating the Baryon asymmetry!? Observed*: _ (n B -n B ) / n γ = 6 x SM expectation: _ (n B -n B ) / n γ ~ Sakharov 1967: B-violation C & CP-violation non-equilibrium [JETP Lett. 5 (1967) 24] * WMAP + COBE, 2003 n 0.3 B / n γ = (6.1 ± ) x (6.19 ± 0.15 ) x [E. Komatsu et al ApJS 192] 4

5 EDM and symmetries + _ P _ + T + _ A nonzero particle EDM violates P, T and, assuming CPT conservation, also CP Purcell and Ramsey, PR78(1950)807; Lee and Yang; Landau 5

r P T EDM and symmetries A nonzero particle EDM violates P, T and, assuming

6 Klaus Kirch 6 Saclay, Sep 30, 2013 ( ) H B σ σ) ( µ E σ σ) ( d TH H B σ σ µ E) ( σ σ d PH B σ σ µ E σ σ d H + = + = + = r r r r r r r r r r r r r r r r r r P T EDM and symmetries A nonzero particle EDM violates P, T and, assuming CPT conservation, also CP Purcell and Ramsey, PR78(1950)807; Lee and Yang; Landau

7 Today s most spectacular (Standard) Particle Physics: Direct production of new particles... and detection of decay products... at the energy frontier: LHC 14 TeV 7

8 A complementary approach: Effects of new particles in loops... W - γ µ e+γ µ ~ e ~ γ µ - ν µ ν e e - µ e - 0 ~χ ! ?... can be measured best when the expected contribution is small. or very well known. 8

9 A complementary approach: Effects of new particles in loops... nedm... can be measured best when the expected contribution is small. or very well known. Precision frontier high mass scales 9

10 Standard Model EDM-expectations? Leptons: electroweak negligible Neutron, proton, nuclei: electroweak negligible, strong? 10

11 Standard model lepton EDMs Fourth order electroweak, F. Hoogeveen: The Standard Model Prediction for the Electric Dipole Moment of the Electron, Nucl. Phys. B 241 (1990) new physics? 11

12 Standard model lepton EDMs Fourth order electroweak, F. Hoogeveen: The Standard Model Prediction for the Electric Dipole Moment of the Electron, Nucl. Phys. B 241 (1990) 322 Completely negligible at any experimental sensitivity we can imagine today! + new physics? Much greater sensitivity to new, CP-violating physics! 12

13 Standard model lepton EDMs Fourth order electroweak, Completely negligible at any experimental sensitivity we can imagine today! F. Hoogeveen: The Standard Model Prediction for the Electric Dipole Moment of the Electron, Nucl. Phys. B 241 (1990) 322 Expect from SM, approximately: d e e cm d µ e cm d τ e cm Experimentally so far: d e < 1 x e cm d µ < 2 x e cm d τ < 3 x e cm + new physics? Much greater sensitivity to new, CP-violating physics! 13

14 Neutron: Standard Model prediction - electroweak - See also: Mannel&Uraltsev hep-ph/ : ~10-31 e cm Shabalin 1983, McKellar et al

15 Neutron: Standard Model prediction Completely negligible at any experimental sensitivity we can imagine today! Expect from electro-weak SM, approximately: d n e cm Experimentally so far: d n < 3 x e cm 15

16 The strong CP problem [e cm] QCD L QCD L QCD + g 2 /(32π 2 ) θ QCD GG ~ θ QCD = Smith, Purcell, Ramsey PR108(1957)120 d n e cm θ QCD θ QCD < ~ Why is θ QCD so small? EDM upper limit [e cm] RAL-Sussex-ILL d n < 2.9 x e cm C.A.Baker et al., PRL 97 (2006) πnn here, e.g., d p ~ -4/3 d n and d D ~ d n +d p +d D

17 The SUSY CP problem (for neutron and electron!) [e cm] d n e cm ( 300 GeV/c M SUSY 2 2 )sinφ SUSY Why is φ SUSY so small? (this is testing M already to 10TeV and you may also ask: why are the masses so huge?) EDM upper limit [e cm] SUSY Pospelov, Ritz, Ann. Phys. 318(2005)119 for M SUSY = 500GeV, tan β =

18 The SUSY CP problem (for neutron and electron!) [e cm] d n e cm ( 300 GeV/c M SUSY 2 2 )sinφ SUSY Why is M SUSY so large? (this is testing M already to 10TeV and you may also ask: why are the masses so huge?) EDM upper limit [e cm] SUSY Pospelov, Ritz, Ann. Phys. 318(2005)119 for M SUSY = 500GeV, tan β =

19 See: Adam Ritz, PSI

20 Origin of EDMs This is what we need µ neutron & proton EDMs Solid state EDM effects GdIG,GdYIG, (EU,Ba)TiO 3 EDMs of paramagnetic atoms & molecules Tl,Cs..,YbF,,ThO) PbO,ThO,HfF +,WC.. EDMs of diamagnetic atoms Hg, Xe, Ra, Rn.. Adapted from: Pospelov, Ritz, Ann. Phys. 318 (2005) 119 Saclay, Sep 30, 2013 M. Raidal et al., Eur. Phys. J. C 57 (2008) 13 Klaus Kirch 20

21 Origin of EDMs This is what we need µ neutron & proton EDMs These we can access Solid state EDM effects GdIG,GdYIG, (EU,Ba)TiO 3 EDMs of paramagnetic atoms & molecules Tl,Cs..,YbF,,ThO) PbO,ThO,HfF +,WC.. EDMs of diamagnetic atoms Hg, Xe, Ra, Rn.. Adapted from: Pospelov, Ritz, Ann. Phys. 318 (2005) 119 Saclay, Sep 30, 2013 M. Raidal et al., Eur. Phys. J. C 57 (2008) 13 Klaus Kirch 21

22 Origin of EDMs µ This is what we need CP-violating parameters: should be deduced neutron & proton EDMs These we can access Solid state EDM effects GdIG,GdYIG, (EU,Ba)TiO 3 EDMs of paramagnetic atoms & molecules Tl,Cs..,YbF,,ThO) PbO,ThO,HfF +,WC.. EDMs of diamagnetic atoms Hg, Xe, Ra, Rn.. Adapted from: Pospelov, Ritz, Ann. Phys. 318 (2005) 119 Saclay, Sep 30, 2013 M. Raidal et al., Eur. Phys. J. C 57 (2008) 13 Klaus Kirch 22

23 Origin of EDMs... of mostly composite systems! Direct limits Active R&D µ neutron & proton EDMs Solid state EDM effects GdIG,GdYIG, (EU,Ba)TiO 3 EDMs of paramagnetic atoms & molecules Tl,Cs,YbF,,ThO) Fr,PbO,ThO,HfF +,WC.. EDMs of diamagnetic atoms Hg, Xe, Ra, Rn.. Adapted from: Pospelov, Ritz, Ann. Phys. 318 (2005) 119 Saclay, Sep 30, 2013 M. Raidal et al., Eur. Phys. J. C 57 (2008) 13 Klaus Kirch 23

24 gin of EDMs neutron & proton EDMs State of the art neutron d n < 2.9 x e cm PRL97(2006) Hg-199 d Hg < 3.1 x e cm PRL102(2009) d p < 8 x e cm* Xe-129 d Xe < 6 x e cm PRL86(2001)22 Tl-205 d Tl < 9 x e cm d e < 1.6 x e cm* PRL88(2002) YbF d e < 1.05 x e cm* Nature473(2011)493 muon d µ < 1.8 x e cm PRD80(2009) * using the 1-miracle assumption, i.e. no cancelations with other CP-odd effects. EDMs of diamagnetic atoms Hg, Xe, Ra, Rn.. Only for one fundamental fermion, the muon, a competitive direct EDM-limits exist. The next simple system is arguably the neutron. 24

25 How to measure the neutron (or other) electric dipole moment? B E hν = 2 (µb+d n E) hν = 2 (µb- d n E) h ν = 4 d n E 25

26 The Neutron [Chadwick 1932] +2/3-1/3 +2/3 +2/3-1/3 massive composite no net electric charge unstable spin ½, polarizable electric dipole: no, well electrically polarizable takes part in all interactions.. -1/3 26

27 Ultra-cold neutrons similar to ideal gas with temperatures of milli-kelvin move with velocities of few m/s have kinetic energies of order 100 nev strong magnetic gravitation Fermi potential V F V m = -µb V g = m n gh 300 nev V 60 nev T nev m -1 E n < 300 nev 5 T field -> 300 nev 3 m up -> 300 nev 27

28 Typical neutron experiments CN Beam v CN ~ 1000 m/s t obs ~ 10-3 s ρ ~ cm -3 possibly improved quality at new pulsed sources UCN Storage improved density at new UCN sources v UCN ~ 5 m/s t obs ~ s ρ ~ 10 cm -3 28

29 Use UCN for nedm search Statistics: } Systematics: e.g. v x E effects E B E B = v x E 29

30 The high intensity&precision frontier at PSI Aare PSI East Staff ~1500 PY incl. externally financed ~400 PY PhD students ~300 > 2000 external users Budget ~320MCHF ~10% particle physics related PSI West 30

31 The 590 MeV Ringcyclotron at PSI ma MW 31

32 Intensity machines 32

The intensity frontier at PSI: π, µ, UCN Precision experiments with the lightest

highest intensity pion and muon beams, e.g., more than 10 8 µ + /s at 28 MeV/c The

33 The intensity frontier at PSI: π, µ, UCN Precision experiments with the lightest unstable particles of their kind The world s most powerful proton beam to targets: 590 MeV x 2.4 ma = 1.4 MW Feasibility study for more than µ + /s below 30 MeV/c: HiMB The world s highest intensity pion and muon beams, e.g., more than 10 8 µ + /s at 28 MeV/c The new ultracold PIF neutron source, ramping up, designed for 1000 UCN cm -3 nedm, n2edm UCN South Swiss national laboratory with strong international collaborations 33

High Intensity Proton accelerator & UCN Source

consolidation ) Excellent performance of HIPA and

2012, 2013 UCN-Source - 1st test: 12/2010 -

Improvements in cryo-system during winter

34 High Intensity Proton accelerator & UCN Source 590 MeV Proton Cyclotron ma Beam Current ( performance improving consolidation ) Excellent performance of HIPA and regular beam delivery to UCN during many weeks in 2012, 2013 UCN-Source - 1st test: 12/ Safety approval: 06/ UCN start 08/ Improvements in cryo-system during winter shutdown 11/12 - Reliable performance UCN to nedm 2012; > intensity 90 times over > expect another factor ~10 nedm 34

9m(W) 7 m heavy water moderator thermal neutrons 3.

35 The PSI UCN source DLC coated UCN storage vessel height 2.5 m, ~ 2 m 3 tank cryo-pump UCN guides towards experimental areas 8.6m(S) / 6.9m(W) 7 m heavy water moderator thermal neutrons 3.6m 3 D 2 O cold UCN-converter SV-shutter ~30 dm 3 solid D 2 at 5 K pulsed 1.3 MW p-beam 600 MeV, 2.2 ma, 1% duty cycle spallation target (Pb/Zr) (~ 8 neutrons/proton) 35

36 The PSI UCN source

37 UCN-Start Dec.16/17/22, MW UCN pulse BL

38 Continuous improvement under way 2s Normkicks Expect another factor of 10 in UCN output >~ 38

39 Routine operation since 2012 delivered UCN to nedm 39

40 40

41 Installing nedm at PSI in 2009 nedm.web.psi.ch Coming from ILL Sussex-RAL-ILL collaboration PRL 97 (2006)

42 Orsay 42

43 How to measure the neutron (or other) electric dipole moment? B E hν = 2 (µb+d n E) hν = 2 (µb- d n E) h ν = 4 d n E 43

44 The Ramsey method Spin up neutrons π/2 flip pulse Free precession [K. Green et al, Nucl. Instr. Meth. A 404, 381 (1998)] Neutron clock external clock π/2 flip pulse σ = h 2EαT N Statistical sensitivity α Visibility of resonance E Electric field strength T Time of free precession N Number of neutrons 44

45 Apparatus High voltage lead Vacuum chamber Precession chamber where neutrons precesses E~12 kv/cm B=1 µt E B Electrode (upper) Magnetic field coils B 0 -correction coils 5T magnet to spin polarize UCNs Spin analyzer Switch to distribute the UCNs to different parts of the apparatus Neutron detector 45

46 46

47 47

48 The π/2-pulses seen by CsM Hg-199 T typically s neutron-1 neutron-2 48

49 Optimizing the magnetic field homogeneity 10 pt 1 pt average deviation range of deviations presently in use: 12 Cs magnetometers 33 trim coils 49

50 nedm performance ±63 s 1158±94 s T2 times

4 x 10-25 ecm / cycle = 3 x 10-26 ecm / day = 3 x 10-27 ecm / year 400 s 200 nights After 2

51 Statistical Sensitivity projected (and as of Nov. 2012) α = 0.75 (0.68) E = 12 kv/cm (8.3) T = 150 s (200s) N = (8 000) Obtain same figures with E=10kV/cm, T=130s, 200s cycle = 4 x ecm / cycle = 3 x ecm / day = 3 x ecm / year 400 s 200 nights After 2 years*, statistics only d n = 0: d n < 4 x ecm (95% C.L.) * 200 nights each (~ 2-3 x ecm / day) 51

52 nedm.web.psi.ch Present best limit: d n < 2.9 x ecm Sussex-RAL-ILL collaboration C. A. Baker et al., PRL 97 (2006) nedm collaboration nedm.web.psi.ch 14 groups, ~ 50 people Thank you! Moved from ILL to PSI March 2009 Data taking at PSI (Phase II) Sensitivity goal: 5x10-27 ecm (95% C.L.) Operation of new n2edm apparatus (Phase III) Sensitivity goal: 5x10-28 ecm (95% C.L.) ILL 52

53 International context (nedms) Project Goal (en e.cm ) Result expected ~ 5 x ~ 5 x PNPI@ILL ~ 5 x CryoEDM@ILL ~ 3 x nedm@sns ~ 3 x nedm@triumf ~ 3 x ~ 1 x nedm@tum ~ 5 x

EDM worldwide Neutrons @ILL @ILL,@PNPI @PSI @FRM-2 @RCNP,@TRIUMF @SNS @J-PARC Ions-Muons @BNL @FZJ @FNAL @JPARC Molecules YbF@Imperial PbO@Yale ThO@Harvard HfF+@JILA WC@UMich PbF@Oklahoma Solids

54 EDM Molecules Solids Rough estimate of numbers of researchers, in total ~500 (with some overlap) Atoms

55 nedm.web.psi.ch Thank you! ILL 55

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.

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. These electric dipole moments... seem to me to offer one of the most