Search for a Electric Dipole Moment in...

39
Search for a Electric Dipole Moment in Ra-225 Peter Mueller Argonne National Laboratory

Transcript of Search for a Electric Dipole Moment in...

Page 1: Search for a Electric Dipole Moment in Ra-225xqw.hep.okayama-u.ac.jp/files/FPUA2011/FPUA1010/20... · Schiff moment of 225 Ra, Dobaczewski, Engel (2005) Schiff moment of 199 Hg, Ban,

Search for aElectric Dipole Moment

in Ra-225

Peter Mueller

Argonne National Laboratory

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2

Argonne Cold Atom TrappersArgonne Cold Atom Trappers

Z.-T. Lu, P. Mueller, I. Sulai, K. Bailey, M. Kalita, S.M. Hu, W. Williams, W. Jiang,

T.P. O’Connor, J. Singh, R. Parker, M. Dietrich, R. Holt

Argonne Natl Lab, Univ. of Chicago, Univ. of Kentucky

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Electric Dipole Moment (EDM) Violates Both P and T

+

-

+

-

-

+

T P

EDM Spin EDM Spin EDM Spin

A permanent EDM violates both time-reversal symmetry and parity

Neutron

Diamagnetic Atoms (Hg, Ra)

Paramagnetic Atoms (Tl)Molecules (PbO,YbF)

Quark EDM

Quark Chromo-EDM

Electron EDM

Physics beyond the Standard Model:

SUSY, String…

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The Seattle EDM Measurement

Courtesy of Michael Romalis

2 215 Hz

B dEf

h

µ+

+= ≈

2 215 Hz

B dEf

h

µ−

−= ≈

0.6 nHzf f+ −− <

The best limit on atomic EDM

EDM (199Hg) < 3 x 10-29 e-cmGriffith et al., Phys Rev Lett (2009)

E

E

199Hg stable, high Z, J = 0, I = ½, high vapor pressure

+e

-e

UnitEDM

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Schiff moment of 225Ra, Dobaczewski, Engel (2005)

Schiff moment of 199Hg, Ban, Dobaczewski, Engel, Shukla (2010)

Skyrme Model Isoscalar Isovector Isotensor

SIII 300 4000 700

SkM* 300 2000 500

SLy4 700 8000 1000

Enhancement Factor: EDM ( 225Ra) / EDM (199Hg)

• Closely spaced parity doublet – Haxton & Henley (1983)

• Large intrinsic Schiff moment due to octupole deformation

– Auerbach, Flambaum & Spevak (1996)

• Relativistic atomic structure (225Ra / 199Hg ~ 3)

– Dzuba, Flambaum, Ginges, Kozlov (2002)

EDM of 225Ra enhanced

Ψ− = (|α⟩ − |β⟩)/√2

Ψ+ = (|α⟩ + |β⟩)/√255 keV

|αααα⟩⟩⟩⟩ |ββββ⟩⟩⟩⟩

Parity doublet

225Ra:I = ½

t1/2 = 15 d

225Ra:I = ½

t1/2 = 15 d

ψ ψ ψ ψψ ψ

≡ = +−∑ 0 0

0 0

0 0

ˆ ˆˆ . .

z i i PT

z

i i

S HS S c c

E E

ψ ψ ψ ψψ ψ

≡ = +−∑ 0 0

0 0

0 0

ˆ ˆˆ . .

z i i PT

z

i i

S HS S c c

E E

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225Ra Source

229Th

7.3 kyr

225Ra

15 d

225Ac

10 d

Fr, Rn…

~ 4 hr

β

• ~10 mCi (or 300 ng) 225Ra sources from Oak Ridge Nat’l Lab

• Test source: ~100 µCi (or 100 µg) 226Ra (1600 yr)

233U

159 kyrα

αα

Future Rare Isotope Facility

Yield for 225Ra ~ 1010 - 1012 s-1

Future Rare Isotope Facility

Yield for 225Ra ~ 1010 - 1012 s-1

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Stern man

Geiger counter

Special thanks to our health physicists P. Niquette, L. Sprouse, A. Garcia.

Radium oven

Experiment seems feasible with modest(~ 10 mCi) 225Ra sources.

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EDM measurement on 225Ra

Transverse

cooling

Oven:225Ra

Zeeman

SlowerMagneto-optical

Trap (MOT)

Optical dipole

trap (ODT)EDM

measurement

Why trap 225Ra atoms

• Large enhancement:

EDM (Ra) / EDM (Hg) ~ 102 – 103

• Efficient use of the rare 225Ra atoms

• High electric field (> 100 kV/cm)

• Long coherence times (~ 100 s)

• Negligible “v x E” systematic effect

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7s2 1S0

7p 3P0°

7p 3P1°

7p 3P2°

6d 3D1

6d 3D2

6d 3D3

6d 1D2

7p 1P1°

420 ns

0.4 ms

6 ns

0.7 ms1

70

1e-1

5e-4

2e-6

5e-2

2e-2

2e-3

7e-10

4e-5

6e-4

5e-2

2e-2

Radium Atom Energy Level DiagramV. Dzuba, V. Flambaum et al., PRA 61 (2000)

* Without repump, 1.7 × 104 cycles.

* With repump at 1428 nm, 1.7 × 107 cycles.

• Linewidth ~ 400 kHz

• Cooling 7 µK, 14 mm/s

• B gradient ~ 1 G / cm

483

nm

6 µs

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0-4 -3 -2 -1 0 1 2 3 4

Ra

fluor

esce

nce

sign

al

Probe frequency shift (MHz)

Laser-Trapping of 225Ra and 226Ra Atoms

1S0

3P1

Laser-cooling

3D1

1P1 Repump

100x Ra atomic beam

Ra atom trap!

• Key 225Ra frequencies, lifetimes measuredScielzo et al. PRA (2006)

• 225Ra laser cooled and trapped!Guest et al. PRL (2007)

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1P1

3D1

3/2

3/2 -> 3/2

3/2 -> 1/2

1/2 -> 3/2

1/2 -> 1/2

3/2

1/2

1/2

6999.83 cm-1

F540(4) MHz

4196(2) MHz

7031(2) MHz

ISOLDE: 4195(4) MHz*

*Ahmad et al., Phys. Lett. 133B, 47 (1983)

Ra-226 Ra-225

226Ra and 225RaHyperfine constants and isotope shift on 3D1 - 1P1

Guest et al. PRL (2007)

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Radium Atom Repump Dynamics

1429nm Repumping

to 1P1

3P1

3P0

3D11.5 E3

9.9 E1

Laser-cooling

2000

cm-1

0

N(ν)

Blackbody spectrum@ 298K

(kBT/hc) = 210cm-1)

Bij ρ(ν ij ,T ) =Aij

eE /kBT −1, Bji = gi

g j

Bij

2.2 E2

7.4 E1

3.4 E1

3.4 E1

298 K thermaltransition rates

0.6 ms

1S0

1P1

482nm

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EDM Beamline

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B-Field: Shields, Coils, Magnetometers --- Done

µ-shields: Shielding factor = 3 x 104

Design Goal

B = 10 mG

Stability: < 1 ppm in 100 sec

Uniformity: < 1% / cm

B field < 0.1% / cm, ~ 0.3 ppm / 100s Rb cell magnetometer: Budker design

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Rb Magnetometry

Shields

Rb

Coil

Rb

B

Ra-225

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Rel. B-Field Stabilityx10-7

3

4

100 s ( 3 nG / 10 mG )

5

6

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EDM Science Chamber

Standing wave ODT

Shuttle

ODT

HV Electrodes

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E-Field: 100 kV / cm -- Done.• 20 kV over 2mm vacuum gap• < 50 pA leakage currents observed• ~10-10 Torr UHV in 2 m glass tube

1 cm

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EDM Beamline

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Optical Dipole Trap

20

1

4H dE Eα= − = −% • Fiber laser: λ = 1550 nm, Power = 40 Watts

• Focused to 100 µm � trap depth 400 µK

EDM in an optical dipole trap – Fortson & Romalis (1999)

• v x E , Berry’s phase effects suppressed

• Cold scattering suppressed between cold Fermionic atoms

• Rayleigh scat. rate ~ 10-1 s-1 ; Raman scat. rate ~ 10-12 s-1

• Conclusion: possible to reach 10-30 e cm for 199Hg

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Atom Transfer Steps

(A)

MOTStanding WaveHolding ODT10W 1550 nm

Travelling WaveBus ODT 50W1550 nm

(B)

(C) (D)

714 nmLaser Cooling Polarize and

Measure

483 nm Probe

Mirror

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“iEDM” Beamline

Translation stageiEDM Chamber

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ODT Transport

50 cm

~ 30,000226Ra atoms

• > 50 cm transport

with moving lens

• “lossless” motion

• atom lifetime limited

by vacuum ~ 10 s

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Overlap of Crossed ODTs

Imaging Beam, 714 nm

Optical LatticeHolding ODT

Bus ODT, 1550 nm

5 mm

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Compression and Handoff with 1D MOT

Imaging

B Field

Imaging

Compression

(A) (B)

(C)

> 60% efficiency

DC MOT EDM

-> AC MOT!

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Atom Imaging

Detector

CCD

1.2 m

Page 28: Search for a Electric Dipole Moment in Ra-225xqw.hep.okayama-u.ac.jp/files/FPUA2011/FPUA1010/20... · Schiff moment of 225 Ra, Dobaczewski, Engel (2005) Schiff moment of 199 Hg, Ban,

With Atoms…

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Without Atoms…

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And Again…

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In case you didn’t catch that…

~700 226Ra Atoms

1.4% Absorption

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Precession MeasurementP

opul

atio

n of

m=

-1/2

Time (s)

225Ra

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Next Steps

• 225Ra transfer, pumping and precession

• Shadow imaging of 225Ra

• Installation of EDM science chamber

(shields, coils, electrodes)

• Measurement of EDM to follow

Page 34: Search for a Electric Dipole Moment in Ra-225xqw.hep.okayama-u.ac.jp/files/FPUA2011/FPUA1010/20... · Schiff moment of 225 Ra, Dobaczewski, Engel (2005) Schiff moment of 199 Hg, Ban,

EDM measurement on 225Ra

Transversecooling

Oven:225Ra

Zeeman Slower Magneto-optical

trap

Opticaldipole trap

EDMmeasurement

Statistical uncertainty:

100 kV/cm

10 s 10410%

10 days

δδδδd = 3 ×××× 10-26 e cm

Best experimental limit: d(199Hg) < 3 × 10-29 e cm

Ra / Hg Enhancement factor ~ 102 -103

100 s 106

100 days

δδδδd = 3 ×××× 10-28 e cm

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6He

νe

6Li+

β - θ

T

+

-

EDM Spin

+

-

EDM Spin

He

He

Ra

Kr,Ar

www.phy.anl.gov/mep/atta/google atom trap

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Weak Interaction Studies: ββββ−−−−νννν Angular Correlations

6He

6Li

t1/2=0.808 sec

100%β

0+

1+

Qβ=3.510 MeV

-1.0

-0.5

0.0

0.5

1.0

Cor

rela

tion

Coe

f. a

1.00.80.60.40.20.0

T

A

V

S

-50

-40

-30

-20

-10

0

10

20

a(ex

p) -

a(S

M)

x

10-3

1.00.80.60.40.20.0

Fermi fraction

6He n

21Na

32Ar

38mK

21Na

Atom Trap Ion Trap

ββν

β

ββνβ θθ

E

mb

E

paEN ++∝ )cos(1),(

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Beta-Decay Study with Laser Trapped 6He

Recoil time-of-flight spectrum

• ∼1x109 6He/s production yield• trapping rate ∼2x103 6He/s• ∼0.1% statistics in ∼4 weeks beam time

Atom trap properties• Highly selective capture• No RF fields or space charge• Low temperature sample (mK)• Tight spatial confinement (< 100µm)

250 300 350 400 450

a = -1/3

Cou

nts

Time of Flight, ns

a = +1/3

Optical DipoleTrap (ODT)

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Beta-Decay Study with Laser Trapped 6He

Project funded through Mueller’s DOE Early Career Grant (July 2011 – June 2016)

Collaboration with University of Washington/CENPA

And Michigan State University

Phase I: coincidence detection in MOT - 2012/13

• Aim to measure a with <0.5%

• Use UWash/CENPA tandem to produce 6Hevia 7Li(d,3He)6He @ 18 MeV, 5pmA

• Target & transfer line installed

• ~1x109 6He/s transferred

• MOT apparatus installed at CENPA, 4He trapped

• Electrode structure & detector systemunder design

Phase II: 6He transfer into ODT - 2014/15

• Aim to measure a with ~0.1%

• Develop ODT transfer techniques

• Design “high precision” detector system

Beyond 2015

• Explore applicability to other noble-gasisotopes, e.g. 32Ar, 18,19Ne

• Explore higher intensity sources for 6He

MOT chamber

Electrode &DetectorAssembly

Page 39: Search for a Electric Dipole Moment in Ra-225xqw.hep.okayama-u.ac.jp/files/FPUA2011/FPUA1010/20... · Schiff moment of 225 Ra, Dobaczewski, Engel (2005) Schiff moment of 199 Hg, Ban,

Fundamental Physics

At the Intensity Frontier

Nov. 30th – Dec. 2nd 2011

Working group

Nucleons, Nuclei & Atoms

www.intensityfrontier.org