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EDM Searches in storage rings

EDM Searches in storage rings. July 5, 2012 Frank Rathmann Seminar on Precision Experiments in Storage Rings. Topics. Why EDMs? Search for EDMs using storage rings Two projects , at BNL and Jülich

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EDM Searches in storage rings

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  1. EDM Searches in storage rings July 5, 2012 Frank Rathmann Seminar on Precision Experiments in Storage Rings

  2. Topics • Why EDMs? • Search for EDMs usingstoragerings • Twoprojects, at BNL andJülich • Spin coherence time • First directmeasurement Resonance Method with RF E(B)-fields • Polarimetry • Timeline ofprojects, cooperations, workshops • Summary EDM Searches in storage rings

  3. Whatcausedthe Baryon asymmetry? Carina Nebula: Largest-seen star-birth regions in the galaxy Whathappenedtothe antimatter? • Sakharov (1967):Three conditions for baryogenesis • B number conservation violated sufficiently strongly • C and CP violated,B and anti-Bs with different rates • Evolution of universe outside thermal equilibrium EDM Searches in storage rings

  4. Electric Dipole Moments (EDMs) Permanent EDMs violate parity P and time reversal symmetry T Assuming CPT to hold, combined symmetry CP violated as well. EDMs arecandidatestosolvemysteryof matter-antimatter asymmetry  mayexplainwhywearehere! EDM Searches in storage rings

  5. Historyofneutron EDM limits • Smith, Purcell, Ramsey PR 108, 120 (1957) • RAL-Sussex-ILL(dn 2.9 10-26ecm) PRL 97,131801 (2006) Adoptedfrom K. Kirch EDM Searches in storage rings

  6. Limits for Electric Dipole Moments EDM searches - onlyupperlimits, in (uptonow): Hugeeffortsunderwaytoimprovelimits / find EDMs SensitivitytoNEW PHYSICS beyondthe Standard Model 485. WE-Heraeus-Seminar (July 0406, 2011) SearchforElectric Dipole Moments (EDMs) at Storage Rings http://www2.fz-juelich.de/ikp/edm/en/ EDM Searches in storage rings

  7. Why also EDMs of protons and deuterons? Proton anddeuteron EDM experimentsmayprovideone order highersensitivity. In particularthedeuteronmayprovide a muchhighersensitivitythanprotons. • Consensus in the theoretical community: • Essential to perform EDM measurements on different targets with similar sensitivity: • unfold the underlying physics, • explain the baryogenesis. EDM Searches in storage rings

  8. Search for Electric Dipole Moments NEW: EDM search in time developmentofspinin a storage ring: “Freeze“ horizontal spinprecession; watch fordevelopmentof a verticalcomponent! EDM Searches in storage rings

  9. Search for Electric Dipole Moments NEW: EDM search in time developmentofspinin a storage ring: “Freeze“ horizontal spinprecession; watch fordevelopmentof a verticalcomponent! A magicstorage ring forprotons (electrostatic), deuterons, … Onemachinewithm EDM Searches in storage rings

  10. Twostorage ring projectsbeingpursued Jülich, focus on deuterons, or a combinedmachine BNL forprotons all electricmachine CW and CCW propagatingbeams (from A. Lehrach) (fromR. Talman) EDM Searches in storage rings

  11. BNL Proposal 2 beamssimultaneouslyrotating in an all electricring (cw, ccw) ApprovedBNL-Proposal Submittedto DOEGoal forprotons Circumference Technological challenges ! • Spin coherence time • Beam positioning • Continuouspolarimetry • E - fieldgradients Carry out proofofprincipleexperiments (demonstrators) atCOSY EDM Searches in storage rings

  12. Most recent: Richard Talmansconceptfor a Jülich all-in-onemachine Iron-free, current-only, magnetic bending, eliminates hysteresis B A Formoredetails, seeRichard‘slecture B A EDM Searches in storage rings

  13. The frozen spin Method Fortransverseelectricandmagneticfields in a ring ( ), anomalousspin precession isdescribedby x Magic condition: Spin alongmomentumvector Foranysignof, in a combinedelectricandmagneticmachine For(protons) in an all electric ring (magic) EDM Searches in storage rings

  14. Magic condition: Protons Case 1: fieldonly EDM Searches in storage rings

  15. Magic condition: Protons Case 2: and fields magicenergy magicenergy EDM Searches in storage rings

  16. Magic condition: Deuterons and fields EDM Searches in storage rings

  17. Magic condition: Helions and fields EDM Searches in storage rings

  18. Parameters for Richard Talmans all-in-onemachine Talman/Gebel givemaximumachievablefieldofcoppermagnetsof ~ 0.15 T. • Fitting such a machineintothe COSY buildingfavorslowermomenta. • Couldsomeoneplease check this! EDM Searches in storage rings

  19. EDM at COSY –COolerSYnchrotron Cooler andstorage ring for (polarized) protonsanddeuterons Phase space cooledinternal & extractedbeams COSY … the spin-physics machine for hadron physics Injector cyclotron EDM Searches in storage rings

  20. EDM at COSY –COolerSYnchrotron Cooler andstorage ring for (polarized) protonsanddeuterons Phase space cooledinternal & extractedbeams COSY … an ideal starting point for a srEDM search Injector cyclotron EDM Searches in storage rings

  21. “spin closed orbit vector” makes one turn “spin tune” if ║ ring stable polarization A Spin closedorbit one particle with magnetic moment EDM Searches in storage rings

  22. Spin coherence Weusuallydon‘tworryaboutcoherenceofspinsalong Polarization not affected! Atinjection all spinvectorsaligned (coherent) After some time, spinvectorsget out ofphaseandfullypopulatethecone Situation very different, whenyou deal with Longitudinal polarizationvanishes! In an EDM machinewithfrozenspin, observation time is limited. Atinjection all spinvectorsaligned After some time, thespinvectorsare all out ofphaseand in the horizontal plane EDM Searches in storage rings

  23. Estimateofspincoherencetimes (N.N. Nikolaev) Onesourceofspincoherencearerandomvariationsofthespin tune due tothemomentumspread in the beam and israndomizedby e.g., electroncooling Estimate: Spin coherence time fordeuteronsmaybelarger thanforprotons EDM Searches in storage rings

  24. First measurementofspincoherence time 2011 Test measurementsat COSY Polarimetry: Spin coherence time: decoherence time oscillation capture from Ed Stephenson and Greta Guidoboni EDM Searches in storage rings

  25. Topics • Why EDMs? • Search for EDMs usingstoragerings • Twoprojects, at BNL andJülich • Spin coherence time • First directmeasurement Resonance Method with RF E(B) –fields • Polarimetry • Timeline ofprojects, cooperations, workshops • Summary EDM Searches in storage rings

  26. ResonanceMethodwith RF E-fields spin precession governedby: (* restframe) verticalpolarization RF E-field • Two situations: •  EDM effect •  no EDM effect stored d Polarimeter (dpelastic) • This way, the EDM signalisaccumulatedduringthecycle. • Statistical improvementoversingle turn effectisabout: . • Brings us in therangefor. • But: Flippingfields will leadtocoherent betatron oscillations, withhardto handle systematics. EDM Searches in storage rings

  27. Simulation ofresonanceMethodwith RF E-fieldsfordeuteronsat COSY Parameters: beam energy assumed EDM E-field E-fieldreversedevery Constant E-field Numberofturns Numberofturns EDM Searches in storage rings

  28. Simulation ofresonanceMethodwith RF E-fieldsfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof EDM effectaccumulates Polarimeter determines Numberofturns EDM Searches in storage rings

  29. ResonanceMethodwith „magic“ RF Wien filter Avoidscoherent betatron oscillationsof beam. Radial RF-E andvertical RF-B fieldstoobservespinrotation due to EDM Approach pursuedfor a firstdirectmeasurementat COSY.  „Magic RF Wien Filter“ no Lorentz force „Indirect“ EDM effect Tiltofprecession plane due to EDM RF E(B)-field Observable: Accumulationofverticalpolarizationduringspincoherence time stored d Transversepolarization Polarimeter (dpelastic) • Statistical sensitivityfor in therange torangepossible. • Alignmentandfieldstabilityof ring magnets • Imperfectionof RF-E(B) flipper EDM Searches in storage rings

  30. Operation of „magic“ RF Wien filter Radial E andvertical B fieldsoscillate, e.g., with(here). beam energy Spin coherence time maydepend on excitationand on chosenharmonics (seeKolyaNikolaev‘slecture). EDM Searches in storage rings

  31. Simulation ofresonanceMethod with „magic“ Wien filterfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof Preliminary, based on K. Nikolaevsderivationofthecombinedrotationmatricesof E/B flipperand ring EDM effectaccumulates in . EDM Searches in storage rings

  32. Simulation ofresonanceMethod with „magic“ Wien filterfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof. EDM effectaccumulates in EDM Searches in storage rings

  33. Simulation ofresonanceMethod with Magic Wien filterfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof. EDM effectaccumulates in EDM Searches in storage rings

  34. Some polarimetry issues • srEDMexperimentsusefrozenspinmode, i.e., beam mostlypolarizedalongdirectionofmotion, • most promising ring optionsusecw & ccwbeams. • scattering on C destructive on beam andphase-space, • scatteringon C determinespolarizationofmainlyparticleswith large betatron amplitudes, and • is not capabletodetermine . • Forelasticscattering longitudinal analyzingpowersaretiny (violatesparity). Ideally, use a methodthatwoulddetermine. pCanddC polarimetry isthecurrentlyfavoredapproachforthepEDMexperimentat BNL EDM Searches in storage rings

  35. Exploit observables thatdepend onbeam andtargetpolarization Spin-dependent differential crosssectionfor Analyzing power Spin correlations In scattering, necessary observables are well-knownin therangeMeV (not so foror). EDM Searches in storage rings

  36. How couldone do that, determine? Detector CW CCW cell • Detector determinesofcw & ccwbeamsseparately, based on kinematics. • Alignmentoftargetpolarization along axesbymagneticfields. Leads tounwanted MDM rotations absolute no-goin EDM experiments. Suggestion 1: Use a polarizedstoragecelltarget EDM Searches in storage rings

  37. How couldone do that, determine? Detector Polarizedionsource(~10 MeV) • Collidetwoexternalbeamswithcwandccwstoredbeams. • Energycouldbetunedtomatchdetectoracceptance. • Polarizationcomponentsofprobinglow-energy beam canbemadelarge, wouldbeselectedbyspinrotators in thetransmissionlines. • Luminosityestimatesnecessary(Andro, David, Jörg) Suggestion 2: Usecolliding beam fromexternalsource EDM Searches in storage rings

  38. How couldone do that, determine? Detector CW CCW • Requiresluminosity, -functionsat IP shouldberathersmall. • Advantage oversuggestion 2. isthatsupportsluminosity. • Disadvantageisthatsensitivitycomesmainlyfromtermswithand. • Detailedestimatesnecessary (Andro, David, Jörg). Suggestion 3: Usedirectlyreactionsfromcollidingbeams EDM Searches in storage rings

  39. Luminosityestimateforthecollideroption Conditions: Even undertheseveryoptimisticassumptions, event rate will beratherlow. EDM Searches in storage rings

  40. Topics • Why EDMs? • Search for EDMs usingstoragerings • Twoprojects, at BNL andJülich • Spin coherence time • First directmeasurement Resonance Method with RF E(B) –fields • Polarimetry • Timeline of projects, cooperations, workshops • Summary EDM Searches in storage rings

  41. TechnicallydriventimelineforpEDMat BNL 15 18 12 13 14 16 17 19 20 21 Two years R&D/preparation One year final ring design Two years ring/beam-line construction Two years installation One year “string test” EDM Searches in storage rings

  42. Stepwiseapproach in the JEDI project Time scale: Steps 1 and 2: < 5 years Steps 3 and 4: > 5 years EDM Searches in storage rings

  43. srEDM cooperations International srEDM Network Institutional (MoU) and Personal (Spokespersons …) Cooperation, Coordination srEDMCollaboration (BNL) (spokespersonYannisSemertzidis) JEDI Collaboration (FZJ)(spokespersons: A. Lehrach, J. Pretz, F.R.) • Common R&D • RHICEDM-at-COSY • Beam Position Monitors Polarimetry • (…) Spin Coherence Time • Cooling • Spin Tracking (…) Study Group First directmeasurement Ring Design DOE-Proposal(submitted) CD0, 1, … HGF Application(s) pEDM Ring at BNL JEDI EDM Searches in storage rings

  44. EDM Workshop at ECT* (Trento) October 1-5, 2012 http://www.ectstar.eu/ • Organizingcommittee • Jülich • Hans Ströher h.stroeher@fz-juelich.de • Frank Rathmann f.rathmann@fz-juelich.de • Andreas Wirzbaa.wirzba@fz-juelich.de • Brookhaven • Mei Baimbai@bnl.gov • William Marciano marciano@bnl.gov • Yannis Semertzidis yannis@bnl.gov EDM Searches in storage rings

  45. Summary • Measurementsof EDMs areextremelydifficult, but thephysicsisfantastic! • Twostorage ring projects, at BNL and Jülich • All-in-onemachinewithcopper-onlymagnets • Pursuespincoherence time measurementsatCOSY • First directEDM measurementat COSY Resonance Method with RF E(B) -fields • Polarimeter conceptstobeaddressedbysimulations • JEDI collaborationestablished EDM Searches in storage rings

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