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SPIN – Physics, EDM searches in Storage Rings

SPIN – Physics, EDM searches in Storage Rings. August 14, 2012 Frank Rathmann 5 th GEORGIAN - GERMAN SCHOOL AND WORKSHOP IN BASIC SCIENCE. Topics. Introduction Search for Electric Dipole Moments

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SPIN – Physics, EDM searches in Storage Rings

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  1. SPIN– Physics,EDM searches in Storage Rings August 14, 2012 Frank Rathmann 5th GEORGIAN - GERMAN SCHOOL AND WORKSHOP IN BASIC SCIENCE

  2. Topics • Introduction • Search forElectric Dipole Moments • Spin coherence time • First directmeasurement Resonance Method with RF E(B)-fields • Conclusion SPIN – Physics, EDM searches in Storage Rings

  3. Introduction: Structure of Matter SPIN – Physics, EDM searches in Storage Rings

  4. Introduction: Four interactions (forces) Matter consists of fermions, they attract or repel each other by exchanging bosons. SPIN – Physics, EDM searches in Storage Rings

  5. Introduction: Standard model ofelementaryparticles • All particles (andtheircorresponding anti-particles) feature • mass • charge, and • spin The spinvectorof a particleisassociatedwith a magneticmoment, Fermions Bosons SPIN – Physics, EDM searches in Storage Rings

  6. Burningquestionshttp://particleadventure.org/beyond_start.htmlBurningquestionshttp://particleadventure.org/beyond_start.html • Why do we observe matter and almost no antimatter if we believe there is a symmetry between the two in the universe? • What is this "dark matter" that we can't see that has visible gravitational effects in the cosmos? • Why can't the Standard Model predict a particle's mass? • Are quarks and leptons actually fundamental, or made up of even more fundamental particles? • Why are there exactly three generations of quarks and leptons? How does gravity fit into all of this? SPIN – Physics, EDM searches in Storage Rings

  7. Whatcausedthe Baryon asymmetry? Carina Nebula: Largest-seen star-birth regions in the galaxy Whathappenedtothe antimatter? SPIN – Physics, EDM searches in Storage Rings

  8. Symmetries Physical laws are invariant under certain transformations. • T-Symmetry: C-parity(or Charge parity): • Changessignof all quantizedcharges • electrical charge, • baryon number, • lepton number, • flavor charges, • Isospin (3rd-component) Parity: SPIN – Physics, EDM searches in Storage Rings

  9. Whatcausedthe Baryon asymmetry? Carina Nebula: Largest-seen star-birth regions in the galaxy 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 SPIN – Physics, EDM searches in Storage Rings

  10. Dipole moments • Electric dipolemoment Two electricchargesseparatedby a distance Two magneticchargesseparatedby a distance Magnetic dipolemoment SPIN – Physics, EDM searches in Storage Rings

  11. Particlesmighthave, besidesmass, charge, andspin (magneticmoment), an Electric Dipole Moment ? SPIN – Physics, EDM searches in Storage Rings

  12. 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! SPIN – Physics, EDM searches in Storage Rings

  13. 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 SPIN – Physics, EDM searches in Storage Rings

  14. Limits for Electric Dipole Moments EDM searches - onlyupperlimits, in (uptonow): Hugeeffortsunderwaytoimprovelimits / find EDMs SensitivitytoNEW PHYSICS beyondthe Standard Model SPIN – Physics, EDM searches in Storage Rings

  15. 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. SPIN – Physics, EDM searches in Storage Rings

  16. Search for Electric Dipole Moments NEW: EDM search in time developmentofspinin a storage ring: “Freeze“ horizontal spinprecession; watch fordevelopmentof a verticalcomponent! SPIN – Physics, EDM searches in Storage Rings

  17. 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 SPIN – Physics, EDM searches in Storage Rings

  18. Twostorage ring projectsbeingpursued Jülich, focus on deuterons, or a combinedmachine BNL forprotons all electricmachine CW and CCW propagatingbeams (from A. Lehrach) (fromR. Talman) SPIN – Physics, EDM searches in Storage Rings

  19. Most recent: Richard Talmansconceptfor a Jülich all-in-onemachine Iron-free, current-only, magnetic bending, eliminates hysteresis B A B A SPIN – Physics, EDM searches in Storage Rings

  20. 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 SPIN – Physics, EDM searches in Storage Rings

  21. Magneticmoment, spin, g and G The nuclearmagneton SPIN – Physics, EDM searches in Storage Rings

  22. 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) SPIN – Physics, EDM searches in Storage Rings

  23. Magic condition: Protons Case 1: fieldonly SPIN – Physics, EDM searches in Storage Rings

  24. Magic condition: Protons Case 2: and fields magicenergy magicenergy SPIN – Physics, EDM searches in Storage Rings

  25. Magic condition: Deuterons and fields SPIN – Physics, EDM searches in Storage Rings

  26. Magic condition: Helions and fields SPIN – Physics, EDM searches in Storage Rings

  27. Parameters for Richard Talmans all-in-onemachine Talman/Gebel givemaximumachievablefieldofcoppermagnetsof ~ 0.15 T. • Fitting such a machineintothe COSY buildingfavorslowermomenta. SPIN – Physics, EDM searches in Storage Rings

  28. EDM at COSY –COolerSYnchrotron Cooler andstorage ring for (polarized) protonsanddeuterons Phase space cooledinternal & extractedbeams COSY … the spin-physics machine for hadron physics Injector cyclotron SPIN – Physics, EDM searches in Storage Rings

  29. 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 SPIN – Physics, EDM searches in Storage Rings

  30. “spin closed orbit vector” makes one turn “spin tune” if ║ ring stable polarization A Spin closedorbit one particle with magnetic moment SPIN – Physics, EDM searches in Storage Rings

  31. 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 SPIN – Physics, EDM searches in Storage Rings

  32. Estimateofspincoherencetimes (N.N. Nikolaev) Onesourceofspincoherencearerandomvariationsofthespin tune due tothemomentumspread in the beam and israndomizedby e.g., electroncooling Estimate: Spin coherence time fordeuteronsmaybelarger thanforprotons SPIN – Physics, EDM searches in Storage Rings

  33. First measurementofspincoherence time 2011 Test measurementsat COSY Polarimetry: Spin coherence time: decoherence time oscillation capture from Ed Stephenson and Greta Guidoboni SPIN – Physics, EDM searches in Storage Rings

  34. Topics • Why EDMs? • Search for EDMs usingstoragerings • Twoprojects, at BNL andJülich • Spin coherence time • First directmeasurement Resonance Method with RF E(B) –fields • Polarimetry • Summary SPIN – Physics, EDM searches in Storage Rings

  35. 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. SPIN – Physics, EDM searches in Storage Rings

  36. Simulation ofresonanceMethodwith RF E-fieldsfordeuteronsat COSY Parameters: beam energy assumed EDM E-field E-fieldreversedevery Constant E-field Numberofturns Numberofturns SPIN – Physics, EDM searches in Storage Rings

  37. Simulation ofresonanceMethodwith RF E-fieldsfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof EDM effectaccumulates Polarimeter determines Numberofturns SPIN – Physics, EDM searches in Storage Rings

  38. 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 SPIN – Physics, EDM searches in Storage Rings

  39. 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 SPIN – Physics, EDM searches in Storage Rings

  40. 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 . SPIN – Physics, EDM searches in Storage Rings

  41. Simulation ofresonanceMethod with „magic“ Wien filterfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof. EDM effectaccumulates in SPIN – Physics, EDM searches in Storage Rings

  42. Simulation ofresonanceMethod with Magic Wien filterfordeuteronsat COSY Parameters: beam energy assumed EDM E-field Linear extrapolationoffor a time periodof. EDM effectaccumulates in SPIN – Physics, EDM searches in Storage Rings

  43. 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 SPIN – Physics, EDM searches in Storage Rings

  44. Exploit observables thatdepend onbeam andtargetpolarization Spin-dependent differential crosssectionfor Analyzing power Spin correlations In scattering, necessary observables are well-knownin therangeMeV (not so foror). SPIN – Physics, EDM searches in Storage Rings

  45. 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 SPIN – Physics, EDM searches in Storage Rings

  46. How couldone do that, determine? Detector Polarizedionsource(~10 MeV) • Collidetwoexternalbeamswithcwandccwstoredbeams. • Energycouldbetunedtomatchdetectoracceptance. • Polarizationcomponentsofprobinglow-energy beam canbemadelarge, wouldbeselectedbyspinrotators in thetransmissionlines. • Luminosityestimatesnecessary Suggestion 2: Usecolliding beam fromexternalsource SPIN – Physics, EDM searches in Storage Rings

  47. How couldone do that, determine? Detector CW CCW • Requiresluminosity, -functionsat IP shouldberathersmall. • Advantage oversuggestion 2. isthatsupportsluminosity. • Disadvantageisthatsensitivitycomesmainlyfromtermswithand. • Detailedestimatesnecessary. Suggestion 3: Usedirectlyreactionsfromcollidingbeams SPIN – Physics, EDM searches in Storage Rings

  48. Luminosityestimateforthecollideroption Conditions: Even undertheseveryoptimisticassumptions, event rate will beratherlow. SPIN – Physics, EDM searches in Storage Rings

  49. Stepwiseapproach in the JEDI project Time scale: Steps 1 and 2: < 5 years Steps 3 and 4: > 5 years SPIN – Physics, EDM searches in Storage Rings

  50. 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 SPIN – Physics, EDM searches in Storage Rings

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