Physics of Electric Dipole Moments in Storage Rings

Yannis K. Semertzidis

Brookhaven National Lab

Frascati, 3 October 2005

•EDMs: What do they probe?•Experimental Technique•Physics of Hadronic EDMs

Particles with Spin…

0d

+

-

dd

For a particle with a spin, only the EDMcomponent alongthe spin survives.

+

-

A Permanent EDM Violates both T & P

Symmetries:

+

-

+

-T

+

-P

A Permanent EDM Violates both T & P

Symmetries:

EdEdH

PEdH

EdEdH

EdH

T

How about Induced EDMs?

EEdH

TOK

PEEdH

OK

Edd

EdH

1st order Stark effect. T, P Violation!

EEdH

2nd order Stark effect. Allowed!

MDMs are Allowed…

BdH

BdBdH

T

PBdH

BdBdH

T-Violation CP-Violation

CPT

Andrei Sakharov 1967:

CP-Violation is one of three conditions to enable a universe containing initially equal amounts of matter and antimatter to evolve into a matter-dominated universe, which we see today….

EDM Searches are Excellent Probes of Physics Beyond the SM:

One CP-Violating Phase (CKM), Needs loops with all quark families for a non-zero result (High Order Effect). Predicts negligible values.

SM:

42 CP-Violating Phases, Needs one loop for a non-zero result (First Order Effect).

SUSY:

Electric Dipole Moments in Storage Rings

• For P @ 10-28e·cm, D @ 10-29e·cm most models beyond the SM predict values within our sensitivity:

• SUSY

• Multi-Higgs

• Left-Right Symmetric …

EDM in an Electric Field…

dsd E

dt

+ -E

+

-

d

Precession of a Top in a Gravitational Field

SILL

mgl ,

EdBdt

sd

Usual Experimental Method

Small Signal

Compare the Zeeman FrequenciesWhen E-field is Flipped:

dE421 +

-

TNEd

11

Schiff Theorem:A Charged Particle at Equilibrium Feels no Force……An Electron in a Neutral Atom Feels no Force Either:

0int EEE extTot

…Otherwise it Would be Accelerated…

Neutron EDM Limits

0.1

1

10

100

1000

10000

100000

1000000

50 60 70 80 90

Year

10^

-25

e-cm

Neutron EDM Vs Year

“…at 6 x 10-26 e cm, it is analogous to the Earth's surface being smooth and symmetric to less than 1 µm” (John Ellis).

Schiff Theorem:A Charged Particle at Equilibrium Feels no Force……An Electron in a Neutral Atom Feels no Force Either. However:

int 0Tot extF qE qE Other Forces

…the net E-field is not zero!

Current Atomic EDM Limits

• Paramagnetic Atoms, 205Tl: electron |de| < 1.610-27e·cm (90%CL)

PRL 88, 071805 (2002)

• Diamagnetic Atoms, 199Hg Nucleus: |d(199Hg)| < 2.110-28e·cm (95%CL)

PRL 86, 2505 (2001)

EDM Status

Particle System Limit [ecm]

Electron 205Tl 1.510-27

Mercury 199Hg atom 210-28

Neutron Ultra-Cold n 510-26

Proton 199Hg atom 510-24

Future Prospects:

• Neutron: Ultra-Cold Neutrons & Polarized 3He stored together in a superfluid 4He. Goal 50-1000, S.K. Lamoreaux et al.

• Electron: YbF Ultra-cold molecules. Goal ~1000, B.E. Sauer et al.

• Electron: PbO*, goal ~1000, D. DeMille et al.

Neutron EDM at LANSCEAiming for a Factor of 50

Electric Dipole Moments in Storage Rings

e.g. 1T corresponds to 300 MV/m! Goal: P @ ~10-28e·cm, D @ ~10-29e·cm

Buddt

sd

Hadronic EDMs

8s

CPL GG

163.6 10 e cmn pd d

( ) NND n p Dd d d d

1610 e cmDd

i.e. @ 10-29ecm:1310

A value of QCD =10-13 would create an EDM of

System EDM value

Proton 410-29ecm

Neutron -310-29ecm

Deuteron 110-29ecm

Tl atom 510-31ecm

Hg atom 110-32ecm

cqd

Quark EM and Color EDMs

52c

CP q qq

iL q d F d G q

, 0.5 5.6 0.2c c c c cD q q u d u d u dd d d d d e d d e d d

, 0.7 0.25 0.55 0.5c c cn q q d u d ud d d d d e d d

cqd

i.e. Deuterons and neutrons are sensitiveto different linear combination of quarksand chromo-EDMs. Similarly with the proton.

Deuteron (D) EDM at 310-

27ecm

Relative strength of various EDM limits as a function of left handed down squark mass (O. Lebedev, K. Olive, M. Pospelov and A. Ritz, PRD 70, 016003 (2004) hep-ph/0402023)

D EDM at ~10-29ecm

Sensitivity to right-handed mass

“…

…”

Sensitivity to right-handed mass

1.6 e 0.81 0.16c c cn u d sd d d d

38.7 10 e 0.005c c cHg u d sd d d d

CEDMs for the down quark vs MN3

Deuteron sensitivityat 10-29 ecm

Electric Dipole Moments in Storage Rings

• P @ 10-28e·cm, D @ 10-29e·cm would be the best EDM sensitivity over present or planned experiments for QCD, quark, and quark-chromo (T-odd Nuclear Forces) EDMs.

• P, D, 3He, etc., i.e. a facility to pin down the CP-violation source.

EDM in Storage Rings

• STORI05 Nuclear Physics in Storage Rings workshop, Bonn/Germany, May 2005

• Frascati/Rome, workshop dedicated to EDM in Storage Rings, 1-11 October, 2005

• “Flavour in the Era of the LHC”, EDM presentation, 7-11 November, 2005

• Letter of Intent on the resonance method by the end of 2005.

Extra Slides

S. Lamoreaux at “Lepton Moments”

E=5MV/m,T=108s

R&D

Cost of the n-EDM Experiment at LANSCE

• $10M for the experimental apparatus

• $9M for the Beamline

• R&D?

• Total $19M plus R&D