EdBdt

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Methods of Electric Dipole Moments in Storage Rings

Yannis K. Semertzidis

Brookhaven National Lab

Frascati, 5 October 2005

•Parasitic to g-2•Frozen spin•Resonance

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Experimental Principle of g-2 or EDM:

• Polarize

• Interact:

• Analyze as a function of time

in a B or E-Field

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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The Principle of g-2

Spin vector Non-relativistic case

• B

m

eBc

m

eBgs 2

m

eBa

m

eBg

m

eB

m

eBgacsa

2

2

2

Momentum vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Spin Precession in g-2 Ring(Top View)

Bm

eaa

Momentumvector

Spin vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Effect of Radial Electric Field

• Low energy particle

• …just right

• High energy particle

Spin vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Effect of Radial Electric Field

• …just right

Spin vector

, 29.3

for muons

(~3GeV/c)

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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• The Muon Storage Ring: B ≈ 1.45T, Pμ ≈ 3 GeV/c

•High Proton Intensity from AGS

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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4 Billion e+ with E>2GeV

aa

t

tAeNdtdN

cos1/ 0

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Electric Dipole Moments in Storage Rings

e.g. 1T corresponds to 300 MV/m for relativistic particles

Buddt

sd

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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B

a edm

Ron McNabb’s Thesis 2003: C.L. 95% cme107.2 19

x

y

z

sβ

aω

edm

m

e Ba

Buc

2

Indirect Muon EDM limit from the g-2 Experiment

a

edm

tan

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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The Vertical Spin Component Oscillates due to EDM

Time 8 s

Ver

tica

l Sp

in C

omp

o ne n

t a.

u.

0 s

g-2 period

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Effect of Radial Electric Field

• Low energy particle

• …just right

• High energy particle

Spin vector

Momentum vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Use a Radial Electric Field and a

• Low energy particleSpin vector

Momentum vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Spin Precession in g-2 Ring(Top View)

Bm

eaa

Momentumvector

Spin vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Spin Precession in EDM Ring(Top View)

0a

Momentumvector

Spin vector

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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(U-D)/(U+D) Signal vs. Time

(U-D

)/( U

+D

)

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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B

a edmx

y

z

sβ

aω

edm

m

e Ba

Buc

2

a

edm

tan

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Vertical Spin Component without Velocity Modulation (deuterons)

Time

Ver

tica

l Sp

in C

omp

o ne n

t a.

u.

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Velocity Modulation in Phase with g-2 Precession

Vel

ocit

y-0.

35

Time [ns]

g-2 Precession

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Vertical Spin Component with Velocity Modulation at a

Ver

tica

l Sp

in C

omp

o ne n

t a.

u.

Time

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Vertical Spin Component with Velocity Modulation (longer Time)

Ver

tica

l Sp

in C

omp

o ne n

t a.

u.

75 s Time 0 s

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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EDM Spin Resonance MethodSome of Y. Orlov’s main ideas:

• Synchrotron tune = (a-N), a=(g-2)/2, N=0,1,2,…

• Cancel systematics by the two half beam storage at different vertical tunes

• Use n=1 in the dipole magnets, and p=1 mainly to keep the phase of the g-2 rotation linear with t.

• D-function0 at straight section…

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Two half beam technique

See talk by B. Morse tomorrow

This tune makes its spin more sensitiveto background

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Other Issues

• Spin coherence time. I.B. Vasserman et al., Phys. Lett. B198, 302 (1987); A.P. Lysenko, A.A. Polunin, and Yu.M. Shatunov, Particle Accelerators 18, 215 (1986).

• RF-system: frequency, shape, strength, normal/SC. Is partial linearization needed? C. Ohmori, et al., 14th Symposium on Accelerator Science and Technology, Tsukuba, Japan, Nov. 2003; M. Yamamoto et al., PAC99.

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Storage Ring EDMs

• Interesting Physics

• Study the ideas, improve design

• Contribution level to this effort

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Summary• ~end of the year Letter of Intent

• We need help to develop the final ring lattice and tolerances on parameters

• Goal for a proposal by the end of next year

• A unique opportunity for a significant contribution to the physics of EDM

Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt

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Nuclear Scattering as Deuteron EDM polarimeter

IDEA:- make thick target defining aperture- scatter into it with thin target

D

L

U

R

R

DΔ

“extraction”target - ribbon

“defining aperture”primary target

detectorsystem

Target could beAr gas (higher Z).

Target “extracts” byCoulomb scattering deuterons onto thickmain target. There’snot enough goodevents here towarrant detectors.

Hole is largecompared tobeam. Every-thing that goesthrough holestays in thering.

Detector is far enoughaway that doughnutillumination is not anacceptance issue:Δ < R.

Ed Stephenson’s

Alternative way: resonant slow extraction (Y. Orlov)