Search for permanent electric dipole moments

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1 Mitglied der Helmholtz-Gemeinschaft Search for permanent electric dipole moments June 03, 2015 Frank Rathmann Flavour 2015: New Physics at High Energy and High Precision, MIAPP

2 Outline Introduction Baryogenesis, EDMs & present limits EDM search using storage rings Recent progress Spin coherence time Spin tune measurement First direct, EDM measurement Role of magnetic machine imperfections Technical developments Electrostatic deflectors Conclusion Search for permanent Electric Dipole Moments 2

3 Unsolved Mysteries: Beyond the Standard Model 1. Why do we observe matter and almost no antimatter if we believe there is a symmetry between the two in the universe? 2. What is this "dark matter" that we can't see that has visible gravitational effects in the cosmos? 3. Why can't the Standard Model predict a particle's mass? 4. Are quarks and leptons actually fundamental, or made up of even more fundamental particles? 5. Why are there exactly three generations of quarks and leptons? How does gravity fit into all of this? From f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 3

4 Physics: Observed Baryon Asymmetry Carina Nebula: Largest-seen star-birth regions in the galaxy / Observed WMAP+COBE (2003) SM exp. ~10 Why this strange number? Why not zero? Search for new physics beyond the standard model Mystery of missing antimatter addresses the puzzle of our existence f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 4

5 Physics: Baryogenesis (1967) Ingredients for baryogenesis: 3 Sakharov conditions f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 5

6 EDMs: Discrete Symmetries Not Charge symmetric (aligned with spin) EDM: : : : MDM : EDM Permanent EDMs violate both and symmetry. Assuming to hold, violated also. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 6

7 EDMs: Naive estimate of the nucleon EDM scale Khriplovich & Lamoreux (1997); Nikolaev (2012) & conserving magnetic moment nuclear magneton ~10 e cm 2 A non-zero EDM requires violation: the price to pay is 10, and violation (from K-decays): the price to pay is 10 In summary: In SM (without term): Region to search for BSM physics 0 : f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 7

8 EDMs: Precision Frontier Example: Neutron (nedm) Future goal Adapted from: Nature, Vol 482 (2012) Search for Electric Dipole Moments (EDM) of fundamental particles Search for permanent Electric Dipole Moments 8

9 EDMs: Precision Frontier Nucleon Earth fm 1 fm Present upper limit nedm separation diameter of a thin hair ( 10 m) EDMs are tiny! f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 9

10 Measurement principle: Neutral particle EDM Particle in ground state: 1. Reverse 2. Keep the same One challenge: Shield external sources of B to levels 1 nt. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 10

11 Physics Potential of EDMs J.M. Pendlebury: nedm has killed more theories than any other single exp t f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 11

12 Physics: Present limits of EDMs EDM searches: Up to now only upper limits (in ) Particle/Atom Current EDM Limit Future Goal Electron Muon Neutron Proton Deuteron? 10 No direct measurements of electron (ThO molecule) or proton ( Hg ) EDMs No measurement at all of deuteron EDM Large effort on worldwide scale to improve limits and to find EDMs f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 12

13 Physics: Ongoing/planned Searches new P. Harris, K. Kirch A large worldwide effort f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 13

Prospects of charged particle EDMs: No direct measurements of charged hadron EDMs Potentially higher sensitivity than neutrons protons/deuterons are stable more stored polarized protons/deuterons

14 Prospects of charged particle EDMs: No direct measurements of charged hadron EDMs Potentially higher sensitivity than neutrons protons/deuterons are stable more stored polarized protons/deuterons larger electric fields Approach complimentary to neutron EDM EDM of a single particle not sufficient to identify source? access to Charged particle EDM experiments potentially provide a higher sensitivity than, e.g., nedm f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 14

15 Concepts for sredm: Frozen spin Method For transverse electric and magnetic fields in a ring, the anomalous spin precession is described by Thomas-BMT equation: Ω Magic condition: Spin along momentum vector 1. For any sign of, in a combined electric and magnetic machine, where radial and vertical 2. For 0 (protons) in an all electric ring MeV/c (magic) Magic rings to measure EDMs of free charge particles f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 15

Concept: Rings for EDM searches Place particles in a storage ring Align spin along momentum ( freeze horizontal spin precession) Search for time development of vertical polarization

16 Concept: Rings for EDM searches Place particles in a storage ring Align spin along momentum ( freeze horizontal spin precession) Search for time development of vertical polarization New Method to measure EDMs of charged particles: Magic rings with spin frozen along momentum Polarization buildup ~ f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 16

17 Concepts: Magic Storage ring A magic storage ring for protons (electrostatic), deuterons, 0 B particle / / proton... deuteron Possible to measure,, using one machine with ~ 25 m f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 17

18 Concept: Experimental requirements High precision, primarily electric storage ring alignment, stability, field homogeneity, and shielding from perturbing magnetic fields High beam intensity ( 4 10 per fill) Stored polarized hadrons ( 0.8) Large electric fields ( 10 MV/m) Long spin coherence time ( 1000 s) Efficient polarimetry (analyzing power 0.6, 0.005) Goal: provide to the same level f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 18

19 Concept: Systematics Magnetic fields: Radial field mimics EDM effect when With 10 e cm in a field of 10 MV/m,. / Solution: Use two beams simultanously, clockwise (CW) and counter-clockwise (CCW), the vertical separation of the beam orbits is sensitive to. Use CW and CCW beams to tackle systematics f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 19

20 Concepts: Beat the systematics 2 beams simultaneously rotating in an all electric ring (CW, CCW) CW CCW Polarization EDM Sokolov-Ternov Gravitation CW & CCW beams cancel many systematic effects f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 20

21 Concept: Systematic Orbit splitting (Dave Kawall) Splitting of beam orbits: 0.1denotes the vertical betatron tune 1 10 m Modulate 1cos, with 0.1 Splitting corresponds to ft In one year of measurement: 10 fills of 1000 s each ft per fill Required sensitivity 1.25 ft Hz, achievable only with state-of-the-art SQUID magnetometers. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 21

Recent Progress: Magnetic shielding Next generation nedm experiment under development at TUM (FRM II): Goal: Improve present nedm limit by factor 100.

22 Recent Progress: Magnetic shielding Next generation nedm experiment under development at TUM (FRM II): Goal: Improve present nedm limit by factor 100. Experiment shall use multi-layer shield. Applied magnetic field: B T. J. Appl. Phys. 117 (2015) At mhz frequencies, damping of 1 10 achieved f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 22

23 Insert: Spin closed orbit and spin tune Spin closed orbit one particle with magnetic moment makes one turn nˆco spin closed orbit vector ring S A A spin tune 2 S A 2 s stable polarization S if nˆco The number of spin precessions per turn is called spin tune f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 23

24 Challenge: Spin coherence time (SCT) We usually don t worry about coherence of spins along Polarization along not affected! At injection all spin vectors aligned (coherent) After some time, spin vectors get out of phase and fully populate the cone Situation very different, when you deal with machines with frozen spin. nˆco Longitudinal polarization vanishes! At injection all spin vectors aligned Later, spin vectors are out of phase in the horizontal plane In a machine with frozen spins the buildup time to observe a polarization is limited by. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 24

25 EDM at COSY: COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons.. / Phase space cooled internal & extracted beams COSY Injector cyclotron the an spin-physics ideal starting machine point for hadron EDM search physics f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 25

26 Spin coherence time: Experimental investigation polarimeter free precession turn spin 1. Vertically polarized deuterons stored in COSY at 1 2. The polarization is flipped into horizontal plane with RF solenoid (takes 200 ms). 3. Beam slowly extracted on Carbon target with ramped bump or by heating the beam. 4. Horizontal (in-plane) polarization determined from Up-Do asymmetry in the detector. Need to keep track of event time and revolution time from turn to turn f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 26

13, 781 khz 0.143, 0.161, 1 sin, 2 120 khz f.

27 Polarimeter: Experimental investigation of SCT Detect deuterons from scattering: Deuterons at 1 GeV 1.13, 781 khz 0.143, 0.161, 1 sin, khz f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 27

28 Polarimeter: Determination of SCT Observed experimental decay of asymmetry as function of time,. Search for permanent Electric Dipole Moments 28

29 Polarimeter: Optimization of SCT Using sextupole magnets in the machine, higher order effects can be corrected, and the SCT is substantially increased Search for permanent Electric Dipole Moments 29

30 SCT: Optimization Measurements of the horizontal polarization lifetime as a function of the strength of the MXG sextupole family with MXS set to 10% and MXL set to 1.45% of power supply full scale. Excellent progress towards the SCT goal for pedm: ~ s f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 30

31 Spin tune : How to m? Number of spin precessions revolution, a priori not known ( ) Detector rate is 5 khz, 781 khz one hit in detector per 25 beam revolutions Scan in an interval around and find maximum of asymmetry Solution: Map all events into one spin oscillation period f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 31

32 Spin tune: D Monitor phase of asymmetry with fixed during 100 s cycle 1 d 2 d Δ Spin tune determined to 10 in 2 s time interval, and in a 100 s cycle at 40 sto 10 (see arxiv: , 2015) f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 32

33 Precision tool for accel. physics: Spin tune Observed behavior of subsequent cycles Tool to optimze long term stability of a machine Develop feedback systems to minimize variations Phase-locking the spin precession to RF devices possible f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 33

34 Idea for proof-of-principle sredm experiment Use an RF technique: RF device operates on some harmonic of the spin precession frequency accumulate EDM signal with time Use COSY for a first direct and EDM measurement f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 34

35 First direct dedm measurement : RF Wien filter Avoids coherent betatron oscillations of beam. Radial RF-E and vertical RF-B fields to observe spin rotation due to EDM. Magic RF Wien Filter no Lorentz force Indirect EDM effect RF E(B)-field stored d Polarimeter (dp elastic) In-plane polarization Observable: Accumulation of vertical polarization during spin coherence time Statistical sensitivity for in the range to range Alignment and field stability of ring magnets Imperfection of RF-E(B) flipper f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 35

First direct EDM measurement: Deuterons Parameters: beam energy 50 MeV RF 1 m assumed EDM 10 ecm E-field 30 kv/cm 2 3.

36 First direct EDM measurement: Deuterons Parameters: beam energy 50 MeV RF 1 m assumed EDM 10 ecm E-field 30 kv/cm Hz EDM effect accumulates in (see Phys. Rev. ST AB 16, (2013)) f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 36

37 First direct EDM measurement: Deuterons Parameters: beam energy 50 MeV RF 1 m assumed EDM 10 ecm E-field 30 kv/cm EDM effect accumulates in Linear extrapolation of for a time period of 1000 s turns yields a sizeable ~. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 37

38 RF Wien Filter: Prototype Insert RF- dipole into ceramic chamber Commissioned prototype just performs like an RF solenoid Search for permanent Electric Dipole Moments 38

RF Wien filter: Strip line design Strip line design provides BPM

8 10 ev m Copper electrodes Device rotatable by 90 in situ

installed in PAX low- section Strip-line RF Wien filter

39 RF Wien filter: Strip line design Strip line design provides BPM (Rogowski coil) RF feedthrough Tmm ev m Copper electrodes Device rotatable by 90 in situ Ferrit cage Mechanical support from exit flange Device will be installed in PAX low- section Strip-line RF Wien filter available end of f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 39

40 Systematic study: Machine imperfections using two straight section solenoids Systematic effects from machine imperfections limit the achievable precision in an EDM experiment using an RF EBWien filter. Idea: Exploit precise determination of spin tune to map out the magnetic imperfections of machine. 10 in a cycle COSY provides two solenoids in opposite straight sections: 1. one of the compensation solenoids of the 70 kv cooler:., 2. The main solenoid of the 2 MV cooler:.. Both devices available dynamically in the cycle, i.e., their strength can be adjusted on flat top. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 40

41 Systematic study: Thomas-BMT eq. 0 in magnetic machine Goal: explore dynamics and systematic limitations of EDM searches in magnetic ring Ω Ω 1 BMT for magnetic machine with 0: Ω Ω Interaction of EDM with motional E-field ) tilts stable spin axis: sin cos tan 2 2 Misalignment of magnetic elements produces in-plane imperfection magnetic fields: Non-vanishing and generate background to the EDM-signal of an ideal imperfection-free machine ( sin, cos and 0). The challenge is to control this background: An accuracy, 10 rad amounts to a sensitivity 10 e cm. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 41

42 Systematic study: Imperfection measurement Probing the in-plane imperfection fields by introducing artificial imperfections and looking for the spin tune response Use the compensation and e-cooler solenoids in straight sections (points 1 and 2): spin kicks and. The values of,, and, depend of spin kicks in non-vertical imperfection fields in the arcs spin tune perturbed:,,, Probe the in-plane imperfection fields by introducing well-known artificial imperfections and. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 42

43 Systematic study: Measurement of spin tune shift Take multiple measurements with different,, build a spin tune map Δ, f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 43

ring with unprededented precision With the baseline spin tune at 0.160971917, one finds: 0.

44 Systematic study: Mapping imperfections Map translated to 2 2 Δ, Fit map to locate saddle point Spin tune mapping allows experimental reconstruction of spin closed orbit in storage ring with unprededented precision With the baseline spin tune at , one finds: f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 44

45 Challenges: Overview Charged particle EDM searches require the development of a new class of high-precision machines with mainly electric fields for bending and focussing. Issues are: Electric field gradients ~17 Spin coherence time 1000 s Continuous polarimetry 1 ppm Beam position monitoring 10 nm Spin tracking tools at ~2 cm plate distance These issues must be addressed experimentally at existing facilities f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 45

46 Challenge: Electric field for magic rings Protons: Radial field only 100 Proton EDM 80 radius (m) r1( E) MV/m m E E-field (MV/m) Challenge to produce large electric field gradients f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 46

47 Challenge: Niobium electrodes DPP stainless steel fine-grain Nb Show one slide on JLAB data HV devices large-grain Nb large-grain Nb single-crystal Nb Large-grain Nb at plate separation of a few cm yields ~20 MV/m f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 47

May 2014: Transfer of separator unit plus equipment from FNAL to Jülich Need to develop new electrode

48 Challenge: Electric deflectors for magic rings Electrostatic separators at Tevatron were used to avoid unwanted interactions Electrodes made from stainless steel Routine operation at 1 spark/year at 6 MV/m May 2014: Transfer of separator unit plus equipment from FNAL to Jülich Need to develop new electrode materials and surface treatments f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 48

49 Timeline: Stepwise approach towards all-in-one machine Step Aim / Scientific goal Device / Tool Storage ring Spin coherence time studies Horizontal RF-B spin flipper COSY Systematic error studies Vertical RF-B spin flipper COSY COSY upgrade Orbit control, magnets, COSY First direct EDM measurement at? Built dedicated all-in-one ring for,, 3 He EDM measurement of,, 3 He at RF-E(B) spin flipper Common magneticelectrostatic deflectors Modified COSY Dedicated ring Dedicated ring Time scale: Steps 1 and 2: years Steps 3 and 4: years f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 49

Novosibirsk, St Petersburg, Stockholm, Tbilisi, http://collaborations.fz-juelich.

50 JEDI Collaboration JEDI = Jülich Electric Dipole Moment Investigations May the force be with us! ~100 members (Aachen, Dubna, Ferrara, Indiana, Ithaka, Jülich, Krakow, Michigan, Minsk, Novosibirsk, St Petersburg, Stockholm, Tbilisi, ~10 PhD students f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 50

51 Conclusion EDMs offer new window to disentangle sources of violation, and to explain matter-antimatter asymmetry of the universe. First direct EDM measurements (, ) at COSY ~10 e cm 2018 Development of a dedicated EDM storage ring 10 e cm Conceptual design report 2018 Spin tune determination emerges as novel precision tool for accelerators Allows mapping magnetic imperfections in a machine Development of high-precision spin tracking tools, incl. RF structures. Development of electrostatic deflectors (also ), BPMs etc. sredm experiments are very challenging, but the physics is fantastic. f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 51

Georg Christoph Lichtenberg (1742-1799) Man muß etwas Neues

52 Georg Christoph Lichtenberg ( ) Man muß etwas Neues machen, um etwas Neues zu sehen. You have to make (create) something new, if you want to see something new Search for permanent Electric Dipole Moments 52

53 Publications Experiment: 1. A. Lehrach, B. Lorentz, W. Morse, N.N. Nikolaev, F. Rathmann, Precursor Experiments to Search for Permanent Electric Dipole Moments (EDMs) of Protons and Deuterons at COSY, e-print: arxiv: (2012). 2. N.P.M. Brantjes et al., Correcting systematic errors in high-sensitivity deuteron polarization measurements, Nucl. Instrum. Meth. A664, 49 (2012), DOI: /j.nima P. Benati et al., Synchrotron oscillation effects on an rf-solenoid spin resonance, Phys. Rev. ST Accel. Beams 15 (2012) , DOI: /PhysRevSTAB Frank Rathmann, Artem Saleev, N.N. Nikolaev [JEDI and sredm Collaborations], The search for electric dipole moments of light ions in storage rings, J. Phys. Conf. Ser. 447 (2013) , DOI: / /447/1/ Z. Bagdasarian et al., Measuring the Polarization of a Rapidly Precessing Deuteron Beam, Phys. Rev. ST Accel. Beams 17 (2014) , DOI: /PhysRevSTAB F. Rathmann et al. [JEDI and sredm Collaborations], Search for electric dipole moments of light ions in storage rings, Phys. Part. Nucl. 45 (2014) 229, DOI: /S D. Eversmann et al. [JEDI Collaboration], New method for a continuous determination of the spin tune in storage rings and implications for precision experiments, eprint arxiv: (2015) Theory: J. Bsaisou, J. de Vries, C. Hanhart, S. Liebig, Ulf-G. Meißner, D. Minossi, A. Nogga, A. Wirzba, Nuclear Electric Dipole Moments in Chiral Effective Field Theory, Journal of High Energy Physics 3, 104 (2015), DOI: /JHEP03(2015)104 f.rathmann@fz-juelich.de Search for permanent Electric Dipole Moments 53

Storage Ring Based EDM Search Achievements and Goals

Mitglied der Helmholtz-Gemeinschaft Storage Ring Based EDM Search Achievements and Goals October 20, 2014 Andreas Lehrach RWTH Aachen University & Forschungszentrum Jülich on behalf of the JEDI collaboration