search for a electric dipole moment in...
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![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,](https://reader034.vdocuments.us/reader034/viewer/2022050611/5fb272958d07bc7c042a3572/html5/thumbnails/1.jpg)
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
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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
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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
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Fundamental Physics
At the Intensity Frontier
Nov. 30th – Dec. 2nd 2011
Working group
Nucleons, Nuclei & Atoms
www.intensityfrontier.org