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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).

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Electric dipole moments a search for new physics

Electric dipole moments:

a search for new physics

E.A. Hinds

Imperial College London

Manchester, 12 Feb 2004


Fundamental inversions

Fundamental inversions

C particle antiparticle

(Q -Q)

Pposition inverted

(r -r)

Ttime reversed

(t -t)


Electric dipole moments a search for new physics

Weak interactions are not symmetric under P or C

normal matter - n, m, p - 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.

Symmetries


Electric dipole moments a search for new physics

Electric dipole moment (EDM)

breaks P and T symmetry

P

spin

-

+

+

(P no big deal)

elementary particle

-

edm

+

+

T

-

-

(CP big deal)


Electric dipole moments a search for new physics

EDM is effectively zero in standard model

but

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

Two motivations to measure EDMs


Electric dipole moments a search for new physics

A bit of history

neutron:

Electro-

10-20

10-20

magnetic

electron:

10-22

10-22

10-24

10-24

Experimental Limit on d (e.cm)

10-26

Multi

SUSY

Higgs

f ~ 1

10-28

f ~ a/p

Left-Right

10-30

10-30

1960

1970

1980

1990

2000

10-32

10-34

Standard Model

10-36

10-38


Electric dipole moments a search for new physics

CP from particles to atoms (main connections)

atom/molecule

level

nuclear

level

nucleon

level

electron/quark

level

field theory

CP model

de

thallium

Higgs

SUSY

Left/Right

dq

dcq

neutron

Schiff

moment

NNNN

mercury

Strong

CP

qGG

~


Electric dipole moments a search for new physics

The Mercury EDM experiment

University of Washington, Seattle

M.V. Romalis, W.C. Griffith, J.P. Jacobs, E.N. Fortson

B

+ dE

±

E

- dE

Nuclear spin polarised 199Hg vapor in a double cell

hw = mB

w± measured optically


Gsi992

GSI992

Difference of precession frequencies gives 199Hg EDM

199 Hg EDM (10-27 e.cm)

E = 9 kV/cm

B = 1.5 mTstable to 0.4 pT

Tcoherence~ 100s

Hg edm result:

Phys. Rev. Lett. 86,2505 (2001)

|dHg|<2.110-28e cm


Electric dipole moments a search for new physics

The Neutron EDM

Rutherford-Appleton Laboratory

D Wark, P Iaydjiev, S Ivanov, S Balashov, M. Tucker

Sussex University

PG Harris, JM Pendlebury, D Shiers, M van der Grinten, K Zuber, K Green, m Hardiman, P Smith, J Grozier, J Karamath

ILL

OXFORD

KURE

P Geltenbort

H. Kraus

N Jelley

H Yoshiki

  • Ultracold neutrons in a bottle

precess at frequency (mnB  dnE)/

  • Reverse E to measure dn


Gsi9921

GSI992

E = 4.5 kV/cm

B = 1mT

Tcoherence~ 130s

Hg co-magnetometer

(B is measured to 1 pT rms)

Neutron edm result: Phys. Rev. Lett. 82,904 (1999)

|dn|< 6.310-26e cm


Electric dipole moments a search for new physics

Neutron: longer range plans

New moderators usingliquid helium orsolid deuterium

  • Helium (ILL, LANL)

    Inside the helium

    Higher neutron density

    Higher E field

  • Deuterium (PSI, TU-Munich)

    Outside the deuterium

    Higher neutron density

    Bigger volume (fast moderation)

Aiming at 3 10-28 e.cm over next decade


Electric dipole moments a search for new physics

Implications of n and Hg for the theta parameter

Baluni

Crewther

Pospelov

induces neutron EDM

CP strong interaction

g

p 

×

n

n

p

gs2

q

32p2

induces mercury Schiff moment

Henley & Haxton

Pospelov

×

N

Something

(Peccei-Quinn?)

makes q very small!

p

~

GG

N/

dn10-16 q

 q <610-10

dHg 1 10-18 q

 q <210-10


Electric dipole moments a search for new physics

g

g

squark

squark

q

q

q

q

gaugino

dqq (Fmnsmnig5 ) q

gaugino

1

2

quark color dipole moments

quark electric dipole moments

c

dqq (gsGmnsmnig5 ) q

1

2

scale of SUSY breaking naturally ~200 GeV

CP phase from soft breaking

naturally O(1)

c

dq, dq ~ (loop factor) sinCP

c

du,d, du,d ~ 31024 cm naturally

n and Hg experiments give

du< 2  1025

mq

dd< 5  1026

~ 100 times less!

L

2

c

du< 3  1026

c

dd< 3  1026

Implications of

Hg and n

for SUSY

naturally ~ a/p

CP< 10-2 ??

L> 2 TeV??


Electric dipole moments a search for new physics

CP from particles to atoms (main connections)

atom/molecule

level

nuclear

level

nucleon

level

electron/quark

level

field theory

CP model

de

thallium

Higgs

SUSY

Left/Right

dq

dcq

neutron

Schiff

moment

NNNN

mercury

Strong

CP

qGG


Electric dipole moments a search for new physics

And now for the electron………..


Electric dipole moments a search for new physics

The Thallium EDM experiment

Berkeley

B.C. Regan, E.D. Commins, C.J. Schmidt and D. DeMille

1st huge problem:

motional interaction m  v  E

analyse

polarise

The solution:

add 2 more Tl beams going down

E

± dE

hw = mB

B

±

2nd huge problem:

stray static magnetic fields

analyse

polarise

The solution:

Add 4 Na beams for magnetometry

2 Tl atomic beams

4


Electric dipole moments a search for new physics

A beautiful feature of the method

amplification

de

E

Interaction energy

-deE•

-585 for Tl

atom containing electron

electric field

(Sandars)


Electric dipole moments a search for new physics

 585

÷ 585

Effective field = 72 MV/cm

electron edm result:

|de|< 1.6 10-27 e.cm

|dTl|< 9.4 10-25 e.cm

Final Tl result:PRL 88,071805 (2002)

E = 123 kV/cm

B = 38 mT

Tcoherence = 2.4 ms

Na co-magnetometer


Electric dipole moments a search for new physics

No direct contamination from q problem

- a pure new physics search

g

selectron

de ~ (loop) sinCP

e

e

~ 5  1025 cm

SUSY electron edm

This time natural SUSY is too big by 300

me

L

2

Theoretical consequences of electron EDM

L> 4 TeV??

CP< 310-3 ??


Electric dipole moments a search for new physics

The future for electron EDM experiments

The Imperial experiment uses ytterbium fluoride molecules

E.A. Hinds, B.E. Sauer, J.J. Hudson, P Condylis,

M.R. Tarbutt, R. Darnley

polarmolecules

potentially 1000  more sensitive


Electric dipole moments a search for new physics

First advantage of YbF:

Huge effective field E

Parpia

Quiney

Kozlov

Titov

13 GV/cm

(in Tl experiment hE was 72 MV/cm)


Electric dipole moments a search for new physics

2nd advantage of YbF:

No coupling m v E to motional magnetic field

electron spin is coupled to internuclear axis

and internuclear axis is coupled to E

m

F-

E

Yb+

m E = 0 no motional systematic error


Electric dipole moments a search for new physics

Forming and probing a YbF beam

PMT

1500K heater

YbF beam

Mo

crucible

mirror

Yb and AlF3 mixture

probe laser


Electric dipole moments a search for new physics

The A-X 0-0 band

13

1

3

5

7

9

11

15

17

19

13

1

3

5

7

9

11

15

17

19

174P(8)

174P(8)

174P(9)

174P(9)

174Q(1)

174Q(1)

174Q(0)

174Q(0)

4

5

6

174Q(0)

172P(8)

176P(9)

GHz

0.2

0.4

0.6

0.8

4

5

6

bandhead at 552.1 nm

GHz

GHz


Electric dipole moments a search for new physics

+dehE

| -1 

| +1 

-dehE

170 MHz

| 0 

The lowest two levels of YbF in an electric field E

X2S+ (N = 0,v = 0)

F=1

F=0

Goal: to measure the splitting 2dehE


Electric dipole moments a search for new physics

| +1

| -1 

0

| 0 

E

B

|+1

0 ?

Pump

A-X Q(0) F=1

| -1

Split

Recombine

Probe

170 MHz p pulse

170 MHz p pulse

A-X Q(0) F=0

Phase difference = 2 (mBB+dehE)T/h

Interferometer to measure 2dehE


Electric dipole moments a search for new physics

The Sussex molecular beam

detect

PMT

recombine

B and E

beam

split

pump

oven

1.5 m


Electric dipole moments a search for new physics

Part of the optical setup


The interferometer fringe

The interferometer fringe

Phase difference = 2(mBB+dehE)T/h

Interference signal (kpps)

Magnetic field B (nT)


Electric dipole moments a search for new physics

E

-E

df = 4dehET/h

- 4dehET/h

Detector count rate

-B0

B0

Applied magnetic field

Measuring the edm


Electric dipole moments a search for new physics

Effective field = 13 GV/cm

background

150kHz

fringe height

1.5 kHz

Systematic error

eliminated….

coherence time

1.5 ms

de(24 hrs data)

< 3 10-26 e cm

First YbF result:PRL 89,023003 (2002)

E = 8 kV/cm

B = 6 nT

Tcoherence~1 ms

Limited by counting statistics


Electric dipole moments a search for new physics

Supersonic YbF beam

delay generator

Labview

control and DAQ

YAG laser

1064 or 532 nm

20 mJ in 10 ns

scan

PMT

10 bar Ar

dye laser

550 nm

solenoid valve

target

skimmer


Electric dipole moments a search for new physics

1500K thermal source

10K supersonic source

174 Q(0)

172 P(8)

174 Q(0)

172 P(8)

176 P(9)

200

200

400

400

600

600

0

0

Laser offset frequency (MHz)

Laser offset frequency (MHz)

176 P(9)

3105 useful molecules per second

3107 useful molecules per second


Electric dipole moments a search for new physics

trap

t ~ 1s

E

B

supersonic source

decelerator

recombine

probe

pump

split

interferometer

Possible experiment with trapped molecules


Electric dipole moments a search for new physics

2002

result

cold YbF

beam

trapped

molecules

background

150kHz

640kHz

40kHz

fringe height

1.5 kHz

160 kHz

10 kHz

coherence time

1.5 ms

1 ms

1 s

de in 1 day

3 10-26 e cm

6 10-28 e cm

3 10-30 e cm

long time = narrow fringes

Projections for the future


Electric dipole moments a search for new physics

neutron:

d e.cm

d(muon) 7×10-19

Electro-

10-20

magnetic

electron:

10-22

d(proton) 6×10-23

YbF expt

10-24

d(neutron)  6×10-26

Multi

SUSY

Higgs

d(electron) 1.6×10-27

f ~ 1

10-28

f ~ a/p

Left-Right

10-29

cold

molecules

1960

1970

1980

1990

2010

2020

2030

2000

Current status of EDMs


Electric dipole moments a search for new physics

Conclusion

EDM measurements (especially cold molecules)

have great potential to elucidate

  • particle physics beyond the standard model

  • CP violation

  • matter/antimatter asymmetry of the universe

some of the most fundamental issues in physics


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