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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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slide2

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)

P position inverted

(r -r)

Ttime reversed

(t -t)

slide4

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

slide5

Electric dipole moment (EDM)

breaks P and T symmetry

P

spin

-

+

+

(P no big deal)

elementary particle

-

edm

+

+

T

-

-

(CP big deal)

slide6

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

slide7

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

slide8

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

~

slide9

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

slide11

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

slide13

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

slide14

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

slide15

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??

slide16

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

slide18

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

slide19

A beautiful feature of the method

amplification

de

E

Interaction energy

-deE•

-585 for Tl

atom containing electron

electric field

(Sandars)

slide20

 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

slide21

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 ??

slide22

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

slide23

First advantage of YbF:

Huge effective field E

Parpia

Quiney

Kozlov

Titov

13 GV/cm

(in Tl experiment hE was 72 MV/cm)

slide24

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

slide25

Forming and probing a YbF beam

PMT

1500K heater

YbF beam

Mo

crucible

mirror

Yb and AlF3 mixture

probe laser

slide26

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

slide27

+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

slide28

| +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

slide29

The Sussex molecular beam

detect

PMT

recombine

B and E

beam

split

pump

oven

1.5 m

the interferometer fringe
The interferometer fringe

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

Interference signal (kpps)

Magnetic field B (nT)

slide32

E

-E

df = 4dehET/h

- 4dehET/h

Detector count rate

-B0

B0

Applied magnetic field

Measuring the edm

slide33

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

slide34

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

slide35

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

slide36

trap

t ~ 1s

E

B

supersonic source

decelerator

recombine

probe

pump

split

interferometer

Possible experiment with trapped molecules

slide37

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

slide38

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

slide39

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

ad