Search for Permanent Electric Dipole Moments of Francium Atom
Yasuhiro SAKEMI Research Center for Nuclear Physics (RCNP)
Osaka University
ECR Ion source + Beam line to transport the heavy ions from AVF+
Trap/Cooling Technique↓
Atom EDM search ~ T violation
Time Reversal and EDM
Time Reversal Symmetry ~ Violation ? ~ Test !Dominance of Matter over Antimatter in Universe ?
CPT ~ invariant in quantum field theory : No evidence of violationC: Charge Conjugation ~ violation in weak interaction P: Parity ~ violation in weak interaction T: Time Reversal ~ No evidence of violation
CP: violation was found ~ K0, B decayCPT theorem + CP violation → T violation ?
+-
+-
d
s
T
Electric Dipole Moment
1. Neutron EDM2. Atom EDM
Electron ~ paramagnetic Nucleus (proton) ~ diamagnetic
3. Other particles (ν,μ,τ,Λ0….)
if EDM is observed ~ Beyond the Standard Model
if EDM is measured ~ signal of supersymmetry~ mechanism of SUSY violation
EDM
1.E-38
1.E-35
1.E-32
1.E-29
1.E-26
1.E-23
1.E-20
1.E-17
1.E-14
1.E-11
1.E-08
1945 1955 1965 1975 1985 1995 2005
Year
ED
M(e
cm
) Tl
Supersymmetric: <10-27
Left-right symmetric: 10-26 to 10-28
Higgs models: 3×10-27 to 10-28
Lepton flavor-changing:10-26 to 10-29
Standard model: < 10-38
Best current limit EDM : |de|<1.5×10-27 e・cm from E.D.Commins et al (California), Tl
A challenge is set !
EDM and MSSM
2
sin~
MµθElectron EDM in MSSM → limit to CP-violating phase in MSSM
eL eRγ~
e~
EDM Measurement and Sensitivity
E E
EdhEdBhEdBh
⋅=∆⇒
⋅−⋅=
⋅+⋅=
↑↓
↑↑
42222
νµνµν
Electric dipole moment : d
TNEKehd
⋅⋅⋅⋅⋅=
τδ 111
2Sensitivity :
K: Enhancement factor ~ Atom EDM enhancement E : Electric Field ~ Strong, 100 kV/cm N : Number of Particles ~ Many particles !τ: Coherence Time (Stored time) ~ Long ! (relaxation…) T : Lifetime of Experimentalist ~ Long !
23~ αZd
d
e
atom
∑
∑∑∑
∑
⋅−+
∇⋅+
∇⋅=
−=
≠
iiiie
kjjk
iii
e
iii
e
iiiie
Ed
BedH
ed
EdH
σβ
σσ
σβ
)1(
21,,
'
0
Enhancement factor
0
200
400
600
800
1000
1200
1400
0 20 40 60 80 100
K
Char
ge :
Z
Enhancement factor simple
RbXe Cs
Tl
Fr
Enha
ncem
ent f
acto
r
Charge :Z
Enhancement effects for Atomic EDM
Heaviest Alkali Atom : Francium 210Fr ~ K=1150
1939 found Atomic number 87 Average atomic weight 215 Ionization Potential 4.08 eVRadioactive lifetime of Fr210 =3.2 minNo stable isotopes ~ longest lifetime 223Fr: 22min.
Relativistic effect
Unique points of experiment
1. Heaviest Alkali Atom : Francium EDM enhancement factor :K=1150 ~ Maximum Produced by fusion reaction with high intensity ECR ion source + AVF cyclotronReaction 18/16O + 197Au → 207-211Fr + Xn
2. Extremely cold atom : Bose-Einstein Condensation (BEC) production techniqueCoherence time : τ ~ Long Atoms localized ~ 10 μm order → Applied electric field : E ~ constant High vacuum → High electric field : E ~ possible Ultra cold → small effect of kinematical magnetic field : v×E
3. Rapid cooling ~ Radioactive atom with finite life time ( ~ minutes)Chip trap = Magnetic trap + Evaporation cooling : N,T ~ large
Present status
Micro-Trap
MOT
Atomic beamMOTMOT/PenningMOTTrap
171Yb (p) KyotoXe (p)T.I.T.
TISOLTRIUMFBest limit 205Tl (e)California / LBL
No plan…207-211FrRCNP
First beam Ra (p)TRIuPKVIAtomic structure210FrSUNY
Goal Status Elements ProjectInstitute
Dy,Sm,BaFr
Yb
205TlRa
129Xe 3P2
Others199HgRn129Xe 1S0Nucleus OthersFe3+CsRbElectron
Elements EDM
Experimental Overview
Au targetY neutralizer
Ion transport lenses
18O beam from AVF cyclotron
Cell
Trapped Francium
Chip for Magnetic Trap
Laser Beam
Fr+ ion
Francium production
Fusion Reaction : 18/16O + 197Au → 207-211Fr + Xn
Francium desorbs from the target surface as atoms/ions according to
−
=+
kTEE
nn IPWFexp
21
0
18O beam from AVF
Au target Y targetFr+ ion
Fr atom
To Trap/Cooling
Fr/sec
0
50000
100000
150000
18O Beam Energy (MeV)70 80 90 100 110 120
Francium intensities @ 0.1 uA
210/211Fr
208/209Fr
Target : Gold (Au) ~ EWF(5.1eV)>EIP(4.1eV) → Fr+ ionTarget : Yttrium (Y) ~ EWF(3.1eV)<EIP(4.1eV) → Fr atom
Path to extremely Cold AtomReaction product mud be slowed and cooled from MeV to nano-eV
Magneto-Optical Trap (MOT)
Francium production : 18O + 197Au = 210Fr + 5n
Magnetic Trap and Evaporation Cooling < uK
Bose-Einstein Condensation (BEC)
100 MeV Primary Beam (18O) from AVF cyclotron
Transport Francium
Stop in neutralizer
Vapor in Gas Cell
Laser Trap < nK
Radioactive Atom Finite life time
Fast Trapping/Cooling
MeV
keV
eV
meV
μeV
neV
Microchip Trap
Magnetic trap Realization on Chip Trap for BEC at MPQ
)()( rBurV m ⋅=
r Rapid coolingCompact/easy constructionAtom control ~ magnetic conveyor belt
Microchip Trap
2002Summer
MPQ
Developed at Max-Planck-Institute for Quantum Optics (MPQ) , Prof.Reichel Group
Cooled Atom Collection Sequence
SC-ECR ion source : 18O 1 uA ~100 MeV
1×106 Fr/s production
MOT : 6×106 atoms 6 sec. ~ accumulation
Transfer : MOT to Magnetic Trap
2 sec. ~ accomplished Magnetic Trap : evaporation cooling : 6000 atoms
Measurement Optical Trap : Francium (BEC) : 6000 atoms
EDM measurement with Ultra Cold Francium ~ 10 sec. cycle
EDM measurement
2810~1112
−
⋅⋅⋅⋅⋅=
TNEKehd
τδ
Enhancement factor : K=1150 for Fr E~100kV/cm Coherence time : τ~ 1 sN~6000 atoms @ 1 uA 18O beam
Measurement time : T ~ 60 days needed
If we have 10 days beam time / year → 6years If we have 10 μA ……
Collection efficiency : trapping/cooling technique ECR ion source ~ High intensity Radiation protectionLow cost ~ AVF cyclotron only , RING cyclotron NOT used..Not so much effect to beam time ~ no effect to main physics program at RCNP (high resolution, spin-isospin, cluster…)
Required machine specification
? Fr transport BLS exp. Room? Exist 東 or 西実験室Experimental room
Collaboration 外部資金（2004以降）Rapid cooling Micro Trap
2004in progress Transport to 東・西Beam Line 2004SC ECR 18-24 GHz16/18O : 1~10 μAHeavy Ion Source
Comments Plan Required Spec. Equipments
Physics Experimental feasibility ~ Trap/Cooling technique P-PAC, LOIBudget
Time line ~ other institute (SUNY ..) … ~ within 2 or 3 years
Possibility at RCNP
Beam Line
東実験室
西実験室 リング本体室
中性子実験室New Beam Line1. Nuclear physics ~ heavy ion :
Nuclear magnetic moment 不安定核原子のレーザー核分光Polarized 6Li ion beam Material physics High resolution physics
2. Beam Diagnosis for High Resolution beam3. Basic Physics : Permanent EDM search4. Application
Function : Beam transport ~ achromatic mode (東、西、中性子)Beam diagnosis ~ dispersive mode
Summary
1. Search for permanent EDM of Francium atom Time reversal violation : Test
2. Experimental technique : ECR ion source + AVF direct beam line → Francium atom production New technique : Trap/Cooling ~ collaboration ..
3. Physics with accurate measurement using Trapped/Cooled Atom
