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Electric dipole moments : a search for new physics. E.A. Hinds. Imperial College London. Manchester, 12 Feb 2004. Fundamental inversions. C particle antiparticle. (Q -Q). P position inverted. (r -r). T time reversed. (t -t). - PowerPoint PPT Presentation
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Electric dipole moments: a search for new physics
E.A. Hinds
Manchester, 12 Feb 2004
Imperial College London
Fundamental inversions
C particle antiparticle
P position inverted
T time reversed
(Q -Q)
(r -r)
(t -t)
Symmetries
Weak interactions are not symmetric under P or C
normal matter - n, , - readily breaks C and P symmetry.
The combination CP is different
normal matter respects CP symmetry to a very high degree.
Time reversal T is equivalent to CP (CPT theorem)
normal matter respects T symmetry to a very high degree.
Electric dipole moment (EDM) breaks P and T symmetry
P -+
elementary particle +-
spin
edm
(P no big deal)
+- T +
-(CP big deal)
Two motivations to measure EDMs
EDM is effectively zero in standard modelbut
big enough to measure in non-standard models
direct test of physics beyond the standard model
EDM violates T symmetry
Deeply connected to CP violation and the matter-antimatter asymmetry of the universe
Left-Right
10-32
10-20
10-22
10-24
10-30
MultiHiggs SUSY
Standard Model
Electro-magnetic
10-34
10-36
10-38
Exp
erim
enta
l Lim
it o
n d
(e.
cm)
1960 1970 1980 1990
neutron:
electron:
2000
10-20
10-30
10-22
10-24
10-26
10-28
A bit of history
thallium
atom/moleculelevel
CP from particles to atoms (main connections)
nuclearlevel
NNNNSchiff
momentmercury
HiggsSUSY
Left/Right
StrongCP
field theoryCP model
GG
neutron
nucleonlevel
electron/quark level
de
dq
dcq
~
The Mercury EDM experiment
University of Washington, SeattleM.V. Romalis, W.C. Griffith, J.P. Jacobs, E.N. Fortson
Nuclear spin polarised 199Hg vapor in a double cell
h = B
+ dEE
- dE±
B
± measured optically
199 H
g E
DM
(10
-27 e
.cm
)
GSI992
Hg edm result: Phys. Rev. Lett. 86, 2505 (2001)
|dHg| < 2.110-28 e cm
E = 9 kV/cm
B = 1.5 T stable to 0.4 pT
Tcoherence ~ 100 s
Difference of precession frequencies gives 199Hg EDM
The Neutron EDM
Rutherford-Appleton LaboratoryD Wark, P Iaydjiev, S Ivanov, S Balashov, M. Tucker
Sussex UniversityPG Harris, JM Pendlebury, D Shiers, M van der Grinten, K Zuber, K Green, m Hardiman, P Smith, J Grozier, J Karamath
ILL
P Geltenbort
• Ultracold neutrons in a bottleprecess at frequency (nB dnE)/
• Reverse E to measure dn
OXFORD
H. KrausN Jelley
H Yoshiki
KURE
GSI992
Neutron edm result: Phys. Rev. Lett. 82, 904 (1999)
|dn|< 6.310-26 e cm
E = 4.5 kV/cm
B = 1 T
Tcoherence ~ 130 s
Hg co-magnetometer
(B is measured to 1 pT rms)
Aiming at 3 10-28 e.cm over next decade
Neutron: longer range plans
Helium (ILL, LANL)Inside the heliumHigher neutron densityHigher E field
New moderators using liquid helium or solid deuterium
Deuterium (PSI, TU-Munich)Outside the deuteriumHigher neutron densityBigger volume (fast moderation)
Implications of n and Hg for the theta parameter
gs2
32GG~
CP strong interaction
dn 10-16
610-10n n
p
×
induces neutron EDMBaluniCrewtherPospelov
Henley & HaxtonPospelov
induces mercury Schiff moment
N/
×N
dHg 1 10-18
210-
10
Something(Peccei-Quinn?)
makes very small!
Implications of Hg and nfor SUSY
quark electric dipole moments
dq q (F i5 ) q21
q q
gaugino
squark
quark color dipole moments
q q
g
gaugino
squark
dq q (gs Gi5 ) q21 c
2mqdq, dq ~ (loop factor) sin CP c
CP phase from soft breaking naturally O(1)
scale of SUSY breaking naturally ~200 GeV
naturally ~
du,d, du,d ~ 31024 cm naturallyc
n and Hg experiments give du< 2 1025
dd< 5 1026
du< 3 1026
dd< 3 1026
c
c
~ 100 times less!
CP < 10-2 ??
> 2 TeV ??
thallium
atom/moleculelevel
CP from particles to atoms (main connections)
nuclearlevel
NNNNSchiff
momentmercury
HiggsSUSY
Left/Right
StrongCP
field theoryCP model
GG
neutron
nucleonlevel
electron/quark level
de
dq
dcq
And now for the electron………..
The Thallium EDM experimentBerkeley B.C. Regan, E.D. Commins, C.J. Schmidt and D. DeMille
2 Tl atomic beams
= B
polarise
analyse
± dEE±B
The solution:add 2 more Tl beams going down
4
analyse
polarise
The solution:Add 4 Na beams for magnetometry
1st huge problem:motional interaction v E
2nd huge problem:stray static magnetic fields
A beautiful feature of the method
E
electric field
Interaction energy
-de E•
de
atom containing electron
amplification
-585 for Tl
(Sandars)
Effective field = 72 MV/cm 585
÷ 585electron edm result:
|de|< 1.6 10-27 e.cm
E = 123 kV/cm
B = 38 T
Tcoherence = 2.4 ms
Na co-magnetometer
Final Tl result: PRL 88, 071805 (2002)
|dTl|< 9.4 10-25 e.cm
Theoretical consequences of electron EDM
SUSY electron edm
e e
selectron
2mede ~ (loop) sin CP
No direct contamination from problem
- a pure new physics search
~ 5 1025 cm
This time natural SUSY is too big by 300
CP < 310-3 ?? > 4 TeV ??
potentially 1000 more sensitive
The Imperial experiment uses ytterbium fluoride molecules
E.A. Hinds, B.E. Sauer, J.J. Hudson, P Condylis, M.R. Tarbutt, R. Darnley
The future for electron EDM experiments
polar molecules
0
5
10
15
20
0 10 20 30
Applied field E (kV/cm)
Eff
ecti
ve f
ield
E
(G
V/c
m)
(in Tl experiment was 72 MV/cm)
13 GV/cm
First advantage of YbF: Huge effective field E
ParpiaQuineyKozlovTitov
2nd advantage of YbF:
No coupling v E to motional magnetic field
and internuclear axis is coupled to E
E
E = 0 no motional systematic error
electron spin is coupled to internuclear axis
Yb+
F-
1500K heater
Mocrucible
YbF beam
mirror
probe laser
PMT
Yb and AlF3 mixture
Forming and probing a YbF beam
The A-X 0-0 bandbandhead at 552.1 nm
174P(8)174Q(0)
174P(9)174Q(1)
4 5 6
174P(8)174Q(0)
174P(9)174Q(1)
4 5 6
1 3 5 7 9 11 15 17 19131 3 5 7 9 11 15 17 1913
GHz
GHz
GHz0.2 0.4 0.6 0.8
176P(9)
174Q(0)172P(8)
| -1 | +1
| 0
The lowest two levels of YbF in an electric field E
-deE
+deE
Goal: to measure the splitting 2deE
X2+ (N = 0,v = 0)
F=1
F=0
170 MHz
Interferometer to measure 2deE
Phase difference = 2 (BB+deE)T/
E B
PumpA-X Q(0) F=1
0
| -1 | +1
| 0
Split| -1
|+1
170 MHz pulseProbe
A-X Q(0) F=0
0 ?
Recombine170 MHz pulse
B and E1.5 m
The Sussex molecular beam
bea
m
oven
pump
split
recombine
detect
PMT
Part of the optical setup
135
136
137
-40 -20 0 20 40
The interferometer fringeIn
terf
eren
ce s
ign
al (
kp
ps)
Magnetic field B (nT)
Phase difference = 2(BB+deE)T/
Measuring the edm
Applied magnetic field
Det
ecto
r co
un
t ra
te
E
B0
-E
= 4deET/
-B0
4deET/
E = 8 kV/cm
B = 6 nT
Tcoherence ~ 1 ms
First YbF result: PRL 89, 023003 (2002)
background
fringe height
coherence time
de (24 hrs data)
150kHz
1.5 kHz
1.5 ms
< 3 10-26 e cm
Effective field = 13 GV/cm
Limited by counting statistics
Systematic erroreliminated….
PMT
dye laser550 nm
Supersonic YbF beam
10 bar Ar
solenoid valve target skimmer
YAG laser 1064 or 532 nm20 mJ in 10 ns
delay generator
scan
Labview control and DAQ
0 200 400 600
Laser offset frequency (MHz)
172 P(8)
176 P(9)
174 Q(0)
1500K thermal source
3105 useful molecules per second
0 200 400 600
Laser offset frequency (MHz)
174 Q(0)
172 P(8)
176 P(9)
10K supersonic source
3107 useful molecules per second
Possible experiment with trapped molecules
supersonic sourcedecelerator
pump split
trap ~ 1s
E
B
recombine probe
interferometer
Projections for the future
background
fringe height
coherence time
de in 1 day
2002result
150kHz
1.5 kHz
1.5 ms
3 10-26 e cm
cold YbFbeam
640kHz
160 kHz
1 ms
6 10-28 e cm
trappedmolecules
40kHz
10 kHz
1 s
3 10-30 e cm
long time = narrow fringes
d(muon) 7×10-19
Left-Right
10-20
10-22
10-24
d e.cm
MultiHiggs SUSY
Electro-magnetic
neutron:
electron:
1960 1970 1980 1990 2000 2010 2020 2030
10-28
10-29
Current status of EDMs
d(neutron) 6×10-26
d(proton) 6×10-23YbF expt
coldmolecules
d(electron) 1.6×10-27
Conclusion
EDM measurements (especially cold molecules) have great potential to elucidate
• CP violation
• particle physics beyond the standard model
• matter/antimatter asymmetry of the universe
some of the most fundamental issues in physics