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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

SPIN– Physics,EDM searches in Storage Rings

August 14, 2012 Frank Rathmann

5th GEORGIAN - GERMAN SCHOOL AND WORKSHOP

IN BASIC SCIENCE


Topics
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


Introduction structure of matter
Introduction: Structure of Matter

SPIN – Physics, EDM searches in Storage Rings


Introduction four interactions forces
Introduction: Four interactions (forces)

Matter consists of fermions, they attract or repel each other by exchanging bosons.

SPIN – Physics, EDM searches in Storage Rings


Introduction standard model of elementary particles
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


Burning questions http particleadventure org beyond start html
Burningquestionshttp://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


What caused the baryon asymmetry
Whatcausedthe Baryon asymmetry?

Carina Nebula: Largest-seen star-birth regions in the galaxy

Whathappenedtothe antimatter?

SPIN – Physics, EDM searches in Storage Rings


Symmetries
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


What caused the baryon asymmetry1
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


Dipole moments
Dipole moments

  • Electric dipolemoment

Two electricchargesseparatedby a distance

Two magneticchargesseparatedby a distance

Magnetic dipolemoment

SPIN – Physics, EDM searches in Storage Rings


P articles might have besides mass charge and spin magnetic moment an electric dipole m oment
Particlesmighthave, besidesmass, charge, andspin (magneticmoment), an Electric Dipole Moment ?

SPIN – Physics, EDM searches in Storage Rings


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


History of neutron edm limits
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


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


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


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


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


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


Most recent richard talmans concept for a j lich all in one machine
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


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


M agnetic moment spin g and g
Magneticmoment, spin, g and G

The nuclearmagneton

SPIN – Physics, EDM searches in Storage Rings


The frozen spin method
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


Magic condition: Protons

Case 1: fieldonly

SPIN – Physics, EDM searches in Storage Rings


Magic condition: Protons

Case 2: and fields

magicenergy

magicenergy

SPIN – Physics, EDM searches in Storage Rings


Magic condition: Deuterons

and fields

SPIN – Physics, EDM searches in Storage Rings


Magic condition: Helions

and fields

SPIN – Physics, EDM searches in Storage Rings


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


Edm at cosy cooler synchrotron
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


Edm at cosy cooler synchrotron1
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


“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


Spin coherence
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


Estimate of spin coherence times n n nikolaev
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


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


Topics1
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


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


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


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


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


Operation of magic rf wien filter
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


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


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


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


Some polarimetry issues
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


Exploit observables that depend on beam and target polarization
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


How could one do that determine
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


How could one do that determine1
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


How could one do that determine2
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


Luminosity estimate for the collider option
Luminosityestimateforthecollideroption

Conditions:

Even undertheseveryoptimisticassumptions, event rate will beratherlow.

SPIN – Physics, EDM searches in Storage Rings


Stepwise approach in the jedi project
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


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


    EDM Workshop at ECT* (Trento)

    October 1-5, 2012

    http://www.ectstar.eu/

    SPIN – Physics, EDM searches in Storage Rings


    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

    SPIN – Physics, EDM searches in Storage Rings


    “Man mußetwasNeuesmachen, um etwasNeueszusehen.”

    “You have to make (create) something new,

    if you want to see something new”

    Georg Christoph Lichtenberg (1742-1799)

    SPIN – Physics, EDM searches in Storage Rings


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