Search for Electric Dipole Moments in Storage Rings

Transcription

1 Mitglied der Helmholtz-Gemeinschaft Niccolò Cabeo School 2014 Vacuum and broken symmetries: from the quantum to the cosmos Search for Electric Dipole Moments in Storage Rings May 21, 2014 Frank Rathmann on behalf of JEDI Cabeo School of Physics, Ferrara, Italy

2 Preamble: The big challenges Conventional HEP wisdom, but there is more than that Search for Electric Dipole Moments in Storage Rings 2

3 Preamble: Physics Frontiers Secrets of neutrinos Search for the origin of mass ( Higgs ), SUSY (In-)stability of the proton Precision Quest for Dark Matter and Dark Energy f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 3

4 Preamble: Precision Frontier ESPP, Cracow, September 2012 A most promising additional frontier: Precision f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 4

5 Preamble: So, what are the burning questions? 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? f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 5

6 Outline Introduction Electric Dipole Moments Physics Impact Charged particle EDM searches Concepts for dedicated storage ring searches Technological challenges Precursor experiments Timeline Conclusion Search for Electric Dipole Moments in Storage Rings 6

7 Introduction: Precision Frontier Johann Jakob Balmer (1885) Balmer Series H-atom Striving for the ultimate precision/sensitivity: example hydrogen Search for Electric Dipole Moments in Storage Rings 7

8 Introduction: Precision Frontier Johann Jakob Balmer (1885) Balmer Series H-atom Willis E. Lamb (1947) Lamb-shift (NP 1955) QED g/2 = 1 + α/2π ~ Striving for the ultimate precision/sensitivity f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 8

9 Introduction: Precision Frontier Johann Jakob Balmer (1885) Balmer Series H-atom Gerald Gabrielse (et al.) (2008) Electron MDM SM test ( ) V. Weisskopf: To understand hydrogen is to understand all of physics f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 9

10 Introduction: Why charged particle EDMs? No direct measurements of charged hadrons EDMs Potentially higher sensitivity than neutrons longer life time more stored polarized protons/deuterons larger electric fields Approach complimentary to neutron EDM? = + access to EDM of a single particle not sufficient to identify CPviolating source New approach, with potentially higher sensitivity f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 10

11 Introduction: Precision Frontier Example: Neutron (nedm) Adapted from: Nature, Vol 482 (2012) Search for Electric Dipole Moments (EDM) of fundamental particles Search for Electric Dipole Moments in Storage Rings 11

12 Introduction: Precision Frontier Nucleon Earth fm 1 fm Current upper limit separation size of a hair An EDM is VERY small!! f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 12

13 Outline Electric Dipole Moments Search for Electric Dipole Moments in Storage Rings 13

14 Physics: Electric Dipoles Definition = Example: H 2 O Water molecule: permanent EDM (degenerate GS w/ different Parity) ~ ~! " # $ Charge separation creates an electric dipole f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 14

15 Physics: Fundamental Particles Charge symmetric No EDM (%=) µ: MDM %: EDM Do particles (e.g., electron, nucleon) have an EDM? Search for Electric Dipole Moments in Storage Rings 15

16 Insert: Symmetries Physical laws are invariant under certain transformations Parity: &: ( ) * ( ) * T-Symmetry:,: - - C-parity (or Charge parity): Changes sign of all quantized charges electrical charge, baryon number, lepton number, flavor charges, Isospin (3rd-component) f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 16

17 EDMs: Discrete Symmetries Not Charge symmetric % (aligned w/ spin) Permanent EDMs violate P and T. Assuming CPT to hold, CP is violated also. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 17

18 Outline Physics Impact Search for Electric Dipole Moments in Storage Rings 18

19 Physics: Baryogenesis Big Bang Early Universe Matter Anti-matter Assertion: Universe started with equal amounts of matter and antimatter! Search for Electric Dipole Moments in Storage Rings 19

20 Physics: Baryogenesis Big Bang Early Universe Matter Anti-matter Very soon, a slight asymmetry developed (CP- / T-violation) f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 20

21 Physics: Baryogenesis Big Bang Early Universe Matter anti-matter annihilation photons Matter Anti-matter All the anti-matter annihilated with matter Search for Electric Dipole Moments in Storage Rings 21

22 Physics: Baryogenesis Big Bang Early Universe Matter anti-matter annihilation photons Today Matter Anti-matter Now, only matter is left over! Search for Electric Dipole Moments in Storage Rings 22

23 Physics: Baryogenesis (1967) Ingredients for baryogenesis: 3 Sakharov conditions f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 23

24 Physics: Observed Baryon Asymmetry Carina Nebula: Largest-seen star-birth regions in the galaxy (/ 0 / 0 1)// 4 Observed (6.11±0.19) 10 ;< WMAP+COBE (2003) SM exp. ~10 ;= Why this strange number? Why not zero? Mystery of missing antimatter addresses the puzzle of our existence f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 24

25 Physics: Potential of EDMs J.M. Pendlebury: nedm has killed more theories than any other single expt. Search for Electric Dipole Moments in Storage Rings 25

26 Physics: Limits for Electric Dipole Moments EDM searches: only upper limits yet (in # $ ) Particle/Atom Current EDM Limit Future Goal % > equivalent Electron <.? "" AB <. " " " C# <? " Proton <?." E " " Deuteron? " " E No direct measurement of proton EDM available No measurement at all on the deuteron Huge efforts underway worldwide to improve limits and to find EDMs f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 26

27 Physics: Ongoing/planned Searches new P. Harris, K. Kirch A huge worldwide effort f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 27

28 Outline Charged particle EDM searches Concepts for dedicated Storage Ring searches Search for Electric Dipole Moments in Storage Rings 28

29 Insert: What do we mean by polarized? Most particles posses a magnetic moment, they behave like little magnets Unpolarized ensemble of particles (e.g., protons) B F G ½ I2µ J K F G ½ L= N +N N +N Q K R 0 S 5 10U Polarized ensemble of particles B L =0.71 f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 29

30 Insert: Picture polarized particles stored in a ring f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 30

31 Insert: Magnetic moment, spin, g and G Nuclear magneton Q V W ħ 2 F = JT ; particle spin charge ^ mass _ proton 1 2 f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 31 ` `a b c= b deuteron He electron Qd=e Q V F F f gd e.g., NIST data base:

32 Concept: Frozen spin Method For transverse electric and magnetic fields in a ring (hd K=hd I=0), anomalous spin precession is described by Thomas-BMT equation: ~ j = F i K+ i F J p h d I n i= e 2 2 Magic condition: Spin along momentum vector 1. For any sign ofi, in a combined electric and magnetic machine I= j0kl4m ;jl m 4 m iknhop, where I=I radial and K=K vertical 2. Fori>0 (protons) in an all electric ring i { p =0 J= { j = MeV/c (magic) Magic rings to measure EDMs of free charge particles f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 32

33 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 ~ j =0 gd = d I New Method to measure EDMs of free charged particles: Magic rings with spin frozen along momentum f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 33

34 Concept: Experimental requirements High precision, primarily electric storage ring alignment, stability, field homogeneity, and shielding from perturbing magnetic fields High beam intensity (N=4 10 ;< per fill) Stored polarized hadrons (L = 0.8) Large electric fields (I=10 MV/m) Long spin coherence time ( = 1000 s) Efficient polarimetry (analyzing power œ 0.6,ž=0.005) ˆ a Š & ) Œ - - Ž#ˆ = " # $ Goal: provide ƒ to the same level f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 34

35 Concept: Systematics Magnetic fields: Radial fieldk Ÿ mimics EDM effect whenq K Ÿ I Ÿ With=10 p e cm in a field ofi=10 MV/m, this yields K Ÿ = = ;< ;< ª «.; p ;< ª/ =3.1 10; T Solution: Use two beams simultanously, clockwise (CW) and counter-clockwise (CCW), the separation of the beam orbits is sensitive tok Ÿ. CW and CCW beams to tackle systematics f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 35

36 Concept: Systematics, Orbit splitting (Dave Kawall) Splitting of beam orbits: ±=± lk² ³0 m =±1 10 ;p m µ œ 0.1 denotes the vertical betatron tune Modulateµ œ =µ œ < 1 Fcos ~ {, with F 0.1 Splitting corresponds tok «ft In one year of measurement: 10 fills of1000 s each 0 = ; ft per fill Required sensitivity 1.25 ft Hz, achievable with state-of-the-art SQUID magnetometers. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 36

37 Insert: Storage ring, dynamics and acceptance closed orbit acceptance (beam pipe) ϑ x particle (one of many) x phase space betatron oscillation f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 37

38 Insert: Storage ring, dynamics and acceptance acceptance (beam pipe) ϑ x particle (one of many) x phase space Betatron oscillation Tune µ,œ denotes number of betatron oscillations per turn Machine Resonances if betatron frequency is simple fraction of periodic perturbation frequency Intense beams image charges, intra-beam scattering f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 38

39 Concepts: EDMs Storage ring projects pedm in all electric ring at BNL or at FNAL Jülich, focus on deuterons, or a combined machine (from R. Talman) CW and CCW propagating beams (from A. Lehrach) Two projects: US (BNL or FNAL) and Europe (FZJ) f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 39

40 Concepts: Beat the systematics 2 beams simultaneously rotating in an all electric ring (CW, CCW) CW & CCW beams cancels systematic effects CW CCW Polarization (& * ) EDM(% Œ) Sokolov-Ternov Gravitation Status: Approved BNL-Proposal Submitted to DOE Interest FNAL! Goal for protons % =.E " # $ (¹º# Ž#ˆ ) Many technological challenges need to be met f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 40

41 Concepts: Magic Storage ring A magic storage ring for protons (electrostatic), deuterons, ~ j =0 gd = d I B particle (»#¼/$) Œ (»¼/ ) ½ (¾) proton?.?@". deuteron."@. Possible to measure, %, A# using one machine with ~ 30 m f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 41

42 Concepts: CCW & CCW with magnetic field (all-in-one machine) Iron-free, current-only, magnetic bending, eliminates hysteresis B A A Configuration generates close-to-perfect vertical B field B f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 42

43 Concepts: An all-in-one machine B Maximum achievable field of copper magnets½ Á ~.E T. À= particle (»#¼/$2,.»#¼2 Œ.»¼/ 2 ½.¾ E A#?".@ "E.@.! +.E Very compact machines possible for sredm searches f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 43

44 Concepts: Another Idea - Ivan Koop s spin wheel Âd = d I+Qd K B By appropriate choice of an additional magnetic fieldk Ÿ, the spin vectors can be made to rotate fast in a plane perpendicular to the radius vector frequencies of the order khz The measurement of the polarization buildup as function of time would be replaced by a measurement of the precession frequency. State-of-the-art measurements (SQUIDs) allow forφ 10 U Φ <, Φ < ; Wb is the flux quantum. A bunch of10 ;< protons1cm from a pick-up coil generatesφ 10 «Φ <. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 44

45 Concepts: How Ivan s spin wheel would work? Frequency EDM 0 Find the value of B where spin precession frequency disappears EDM=0 K Ÿ ± This approach has to be worked out in detail. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 45

46 Concepts: Sensitivity Reach JEDI goal: EDM search in charged baryon (systems) pedm dedm Adapted from: Nature, Vol 482 (2012) No direct measurements for proton and deuteron EDM yet! Search for Electric Dipole Moments in Storage Rings 46

47 Outline Technological challenges Search for Electric Dipole Moments in Storage Rings 47

48 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 ʪ at ~2 cm Spin coherence time ( 1000 s) Continuous polarimetry < 1 ppm Beam positioning 10 nm Spin tracking Ë These issues must be addressed experimentally at existing facilities f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 48

49 Challenges: Overview Additional items to be adressed: The measured difference of the CW-CCW beam orbits depends also on the space-charge distribution in the beam. ideal would be a phase-space detector for Î,Î and ±,±, but how to do that? Magnetic machines can be trimmed and shimmed after construction. The design of an electric machine has to be correct from the start, fields are generated by the plate geometry. Therefore, high precision spin tracking calculations have to be carried out in order to validate a design. This involves keeping track of some10 ;< particles for the duration of about1000 g, i.e., for some 10 turns. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 49

50 Challenges: Electric field for magic rings Protons: Radial I field only 100 Proton EDM 80 radius (m) r1( E) I=17 MV/m = m E E-field (MV/m) Challenge to produce large electric field gradients f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 50

51 Challenges: Electric field for magic rings Protons: Radial I and vertical K fields K>0 K<0 magic energy K>0 K<0 magic energy f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 51

52 Challenges: Electric field for magic rings Deuterons: Radial Œ and vertical ½ fields Search for Electric Dipole Moments in Storage Rings 52

53 Challenges: Electric field for magic rings Helions: Radial Œ and vertical ½ fields Search for Electric Dipole Moments in Storage Rings 53

54 Challenges: 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 Electric Dipole Moments in Storage Rings 54

55 Challenges: Electric deflectors for magic rings Electrostatic separators at Tevatron were used to avoid unwanted J J 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 Electric Dipole Moments in Storage Rings 55

56 Challenges: Electric deflectors for magic rings Deflector development will use scaled models ~ 1: 10 Electric fields will be the same, but voltages<20 kv Avoids shielding of x-rays Allows tests to be done in usual lab environment Dedicted clean room being set up at RWTH Aachen Ultrasonic bath Baking system Vacuum system for testing Studies will involve different processing tests with steel steel polishing stainless steel as a base material Development of new deflector materials and treatment methods towards high fields I~20 MV/m f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 56

57 Challenges: Spin coherence time Spin closed orbit one particle with magnetic moment makes one turn nˆco spin closed orbit vector ring r S A A spin tune S r A 2πν s =2Òoi stable polarization S r if nˆco f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 57

58 Insert: Spin manipulation 180 o Snakes There is an /Ó Ô for every point of the orbit Snakes (non-vertical B field) affect /Ó Ô Flippers ramping through a resonance reverses /Ó Ô spin closed orbit f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 58

59 Insert: Spin dispersion A particle beam has momentum spread and betatron amplitude spread Near a resonance individual particles have different /Ó Ô ensemble decoheres and polarization is lost f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 59

60 Challenge: Spin coherence time We usually don t worry about coherence of spins along/ó kõ Polarization 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 withâd /Ó kõ 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 an EDM machine with frozen spin, observation time is limited. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 60

61 Spin coherence time: Estimates (N.N. Nikolaev) One source of spin decoherence are random variations of the spin tune, due to the momentum spread in the beam =i o and o is randomized by e.g., electron cooling, cos~ cos ~ + k 1 ž Ø Ù i p o p 1 J ž Ø Ù i p o p h J p ; Estimate: S ÚÛÜ =100 MeV i =1.79 ž Ø Ù =0.5 MHz i = 0.14 k (J) 3 10 «s k () 5 10 s Spin coherence time for deuterons may be larger than for protons f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 61

62 Spin coherence time: Harmonic dependence Observed oscillatingl œ, driven by RF solenoid at different harmonics ß ž ÝÞ = oi±ß ž Ø Ù àá = 1 J 2Ò p â p ž Ø Ù i p o p h J p ; Spin coherence time (s) K=1 (630 khz) K=-1 (871 khz) 10 8 K=2 (1380 khz) K=2 (1620 khz) Deuterons RF-B solenoid 235 MeV â=1 ä h p 1+ ß oi Theory: N.N.Nikolaev 1 Beam energy (MeV) At specific energies for certain æ decoherence is small. But: Observation of enhancements ofš å for (and%) requires more flexible polarimeter f.rathmann@fz-juelich.de Search for Permanent Electric Dipole Moments at COSY 62

63 EDM at COSY: COoler SYnchrotron Cooler and storage ring for (polarized) protons and deuterons =..? ç#¼/$ Phase space cooled internal & extracted beams COSY Injector cyclotron the an spin-physics ideal starting machine point for a hadron sredmphysics search f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 63

64 Spin coherence time: First measurement 2011 Test measurements at COSY Polarimetry: Spin coherence time: 5 s 25 s 5 s decoherence time oscillation capture f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 64

65 Spin coherence time: Experimental investigation Experimental studies of spin coherence time in a storage ring are rather new. Investigations require to keep track of the event time and the revolution time in each turn during a cycle of a few hundred seconds (time-stamping) Vertically polarized deuterons are stored in COSY at J 1 è ª é The polarization is flipped into the horizontal plane using an RF solenoid, takes about200 ms. Beam is slowly extracted onto EDDA Carbon scattering target during~100 s using a ramped bump or by heating the beam. During this time the horizontal (in-plane) polarization is determined from Up-Do asymmetry in the detector. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 65

66 Polarimeter: Experimental investigation of SCT N ê, 1±L sin í ž Ø Ù, where ž Ø Ù 781 Rîï At J 1 GeV/c, o=1.13 and í =o i= f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 66

67 Polarimeter: How to find the correct í Detector rate is 5 khz, while ž Ø Ù =781 khz one hit in detector per 25 beam revolutions. Solution: Map all events into first period. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 67

68 Polarimeter: How to find the correct í Of course, this only works whens = ; ñ ò ó ôõö is correct f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 68

69 Polarimeter: Scan of í Pick í with maximum amplitude of asymmetry. Search for Electric Dipole Moments in Storage Rings 69

70 Polarimeter: D# # ºˆ ¹º ¹ø í Spin tune í can be determined to 10 = in 2 s Average í ù in cycle (100 s) determined to 10 ;< f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 70

71 Polarimeter: Determination of SCT One observes the experimental decay of the asymmetryú ê = V ûv ü V û ýv ü as function of time, ú ê ( ) L( ). Š þ f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 71

72 Polarimeter: Optimization of SCT Using sextupole magnets in the machine, higher order effects can be corrected, and the SCT is substantially improved Š þ! Excellent progress towards the SCT goal for pedm:å¾~ s f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 72

73 Implications: CPT test with pol. antiprotons Apparently, we are able to determine the spin tune í to a precision of about10 ;<. Suppose, we had a polarized proton beam orbiting clockwise in a magnetic storage ring, and at the same time, a polarized antiproton beam going the opposite way. Both beams on the same orbit, one Rf cavity, etc. Measuring simultaenously the ratio of the spin tunes for the protons and the antiprotons constitutes a hadronic CPT test, capable to determine the ratio of the magnetic moments, at the level of10 ;<. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 73

74 Challenge: Polarimetry Beam polarimetry at ppm level achieved for deuteron beams Search for Electric Dipole Moments in Storage Rings 74

75 Polarimetry: Some issues pc and dc polarimetry is the currently favored approach for the pedm experiments sredm experiments in frozen spin mode have beam mostly polarized along direction of motion, Most promising ring options use cw & ccw beams. scattering on C destructive on beam and phase-space, scattering on C determines polarization of mainly particles with large betatron amplitudes, L is not capable to determinel= L œ, and L is not capable to provide info on phase-space distribution of the beam. For elastic scattering longitudinal analyzing powers are tiny ( violates parity). Ideally, use method that determines L( ), (Î,Î ), and (±,± ) phase-spaces f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 75

76 Polarimetry: Exploit observables that depend on beam and target polarization beam 1 L= L L œ L target.or beam 2) µ µ µ œ µ Spin-dependent differential cross section for ; p + ; p ; p +; p < 1+ œ L œ +µ œ cos+ L +µ sin + L µ cos p +L œ µ œ sin p + L µ œ +L œ µ sincos + œœ L µ sin p +L œ µ œ cos p + L µ œ +L œ µ sincos + L µ +L µ cos+ L œ µ +L µ œ sin + L µ Analyzing power œ = œ Spin correlations =.2 In JdJd scattering, necessary observables are very well-known in the range MeV (not so for Jdd or dd). f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 76

77 Polarimetry: Determine&? Exploit reactions from colliding beams CW beam L= L L œ L CCW beam µ= CW µ µ œ µ Detector CCW < =1+ œ L œ +µ œ cos L +µ sin + L µ cos p +L œ µ œ sin p + L µ œ +L œ µ sincos + œœ L µ sin p +L œ µ œ cos p L µ œ +L œ µ sincos + & ( * +& * ( cos+ & ) * +& * ) sin + & * * Requires luminosity, h-functions at IP should be rather small. Sensitivity comes mainly from terms with Îï and ïï. Detailed estimates necessary. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 77

78 Polarimetry: Luminosity estimate (h) h (S,h) N ;N p ž Ø Ù (S)/ 4Ò (h) p T magic MeV h0.1 m Conditions: ε1 µm N 1 =N / = Luminosity h1 m h10 m kinetic energy (MeV) Under these optimistic assumptions, event rate would be rather low. ˆ #σ p= cm p s ; 10 p cm p mb ; 15mb! f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 78

79 Polarimetry: Alternatives? Alternatives to scattering polarimeter presently under discussion: SQUID based detection, which would move the precision requirements from polarization to frequency Compton Laser back scattering of protons or deuterons Recently, new ideas being discussed for RHIC Advantages: Non-destructive + phase-space detection f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 79

80 Outline Precursor Experiments Search for Electric Dipole Moments in Storage Rings 80

81 Precursor: Three options Goal: Use COSY to determine first upper limit of the EDMs of deuteron and proton All methods are based on making spin precession in machine resonant with the motion around the orbit Two ways: Use an RF device that operates on some harmonics of the spin precession frequency Operate ring on an imperfection resonance 1. Use RF Wien filter to accumulate EDM signal during the spin coherence time 2. Use a static Wien filter on the oi 2 imperfection resonance (for protons only) at S=108.4 MeV 3. Use combination of RF solenoid and RF Wien filter Use existing magnetic machine for first direct EDM measurement. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 81

82 Precursor: 1. Resonance Method with magic RF Wien filter Avoids coherent betatron oscillations of beam. Radial RF-E and vertical RF-B fields to observe spin rotation due to EDM. Approach pursued for a first direct measurement at COSY. Œ Œ = β ½ ) 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 possible. Alignment and field stability of ring magnets Imperfection of RF-E(B) flipper f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 82

83 Precursor: 1. Resonance Method for deuterons Parameters: beam energy S 50 MeV RF =1 m assumed EDM =10 p e cm E-field 30 kv/cm & ( & * & ) ~=2Òž Ÿ io Hz º º # EDM effect accumulates in L œ f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 83

84 Precursor: 1. Resonance Method for deuterons Radial E and vertical B fields oscillate, e.g., with ž ß+io ž Ø Ù = «Hz (hereß=0). beam energy S =50 MeV Spin coherence time depends on excitation and on harmonics ß. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 84

85 Precursor: 1. Resonance Method for deuterons Parameters: beam energy S 50 MeV RF =1 m assumed EDM =10 p e cm E-field 30 kv/cm L ± & ) EDM effect accumulates in L ± º º # Linear extrapolation of& ) for a time period of τ gn =1000 s (= turns) yields a sizeable& ) ~. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 85

86 Precursor: RF Wien Filter 1. Upgrade test flipper with electrostatic field plates ready end of year. 2. Build lower power version using a stripline system 3. Build high-power version of stripline system (I > 100 kv/m) Work by S. Mey, R. Gebel (Jülich) J. Slim, D. Hölscher (IHF RWTH Aachen) f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 86

87 Precursor: RF Wien Filter (Œ ½ prototype) Insert RF-Œ ( dipole into ceramic chamber Prototype already installed and ready for beam. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 87

88 Precursor: RF Wien Filter (field calculations) Main field component K =0.058 mt at ±=0, G1 A, ½! ( %*=.E ¾ Main field component I œ =7594 V/m at y0, U395 V, Œ! ) %*!@@ ¼ Integral compensation of Lorentz force$% œ ï=0at y0 ½ ( (¾) Œ ) (¼/ ) # ) (#¼/ ) * ( ) * ( ) * ( ) RF Œ ½ Wien filter will operate like RF solenoid f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 88

89 Precursor: 2. Resonant EDM measurement with static Wien Filter Machine operated on imperfection spin resonance at&c & ( (-) without static WF Spin rotation in phase with orbit motion - ( ) Similar accumulation of EDM signal, systematics more difficult, strength of imperfection resonance must be suppressed by closed-orbit corrections. f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 89

90 Outline Timeline Search for Electric Dipole Moments in Storage Rings 90

91 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 forj,, 3 He EDM measurement ofj,, 3 He at " # $ RF-E(B) spin flipper Common magneticelectrostatic deflectors Modified COSY Dedicated ring Dedicated ring Time scale: Steps 1 and 2: < E years (i.e., in POF 3) Steps 3 and 4: > E years f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 91

92 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 Electric Dipole Moments in Storage Rings 92

93 Conclusion EDMs offer new window to disentangle sources ofâl violation, and to explain matter-antimatter asymmetry of the universe First direct EDM measurements of and% at COSY (10 p e cm) Development of dedicated EDM storage rings (10 p e cm) All-electric machine (BNL, FNAL) All-in-one machine (Jülich) Development of high precision spin tracking tools, incl. RF structures Electrostatic deflector development based on FNAL equipment f.rathmann@fz-juelich.de Search for Electric Dipole Moments in Storage Rings 93

94 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 Electric Dipole Moments in Storage Rings 94