[email protected], june 2010 the search for permanent electric dipole moments klaus kirch...

[email protected] 1Krakow, June 2010

The search for permanent electric dipole moments

Klaus Kirch ETH Zürich & PSI Villigen

CP violation and electric dipole momentsSystems to work with and their connection to CPVarious comments on the wayInternational status and expectations

Meson2010, June 14th, 2010


What caused the Baryon asymmetry ?

Observed*:(nB-nB) / n = 6 x 10-10

SM expectation:(nB-nB) / n ~ 10-18

Sakharov 1967: B-violationC & CP-violationnon-equilibrium[JETP Lett. 5 (1967) 24]

* WMAP + COBE, 2003 nB / n = (6.1 ± ) x 10-100.3

0.2

_

_


EDM and symmetries

+_

+_

+

_P

TA nonzero particle EDM violates P, T and, assuming CPT conservation, also CP

Purcell and Ramsey, PR78(1950)807; Lee and Yang; Landau


M. Raidal et al., Eur. Phys. J. C 57 (2008) 13

Adapted from:Pospelov, Ritz, Ann. Phys. 318 (2005) 119

,ThO)

EDMs of paramagneticatoms & molecules

Tl,Cs..,YbF,PbO,ThO,HfF+,WC..

neutron & proton EDMs

EDMs of diamagnetic atoms

Hg, Xe, Ra, Rn ..

Solid stateEDM effects GdIG,GdYIG,(EU,Ba)TiO3

AstrophysicalEDM effects neutron stars

Origin of EDMs




,ThO)





Hg, Xe, Ra, Rn ..


AstrophysicalEDM effects? neutron stars, ..

Origin of EDMs

This is what we need




,ThO)





Hg, Xe, Ra, Rn ..



Origin of EDMs


These we can access




,ThO)





Hg, Xe, Ra, Rn ..



Origin of EDMs


These we can access

These should be deduced




,ThO)


Tl,Cs…,YbF,PbO,ThO,HfF+,WC..



Hg, Xe, Ra, Rn ..


AstrophysicalEDM effects, neutron stars, ..

Direct limitsActive R&D

Origin of EDMs


EDM-Search Strategy I

Today: Discovery experimentsnot known which EDM will show up first

search in as many accessible complementary systems as possible

Once discovered:Increase precision (experiment and theory)

Complementary EDM results will constrain models of new physics or even single out the origin of the observed effects


EDM-Search Strategy II

Maximize experimental sensitivity need large polarized sample statistics

need large electric fields

need excellent magnetic field control

the signal is due to the interaction of minute EDMs with an electric field in the presence of magnetic moments and magnetic fields

many background and noise sources and false effects exist, usually related to the electro- magnetic fields


Standard Model EDM-expectations?

Leptons: electroweak negligible

Neutron, proton, nuclei: electroweak negligible, strong?


Standard model lepton EDMsFourth order

electroweak,

F. Hoogeveen:The Standard Model Prediction for the Electric Dipole Moment of the Electron,Nucl. Phys. B 241 (1990) 322

… + new physics?


Fourth order electroweak,


… + new physics? Much greater sensitivity to new, CP-violating physics!

Completely negligible at any experimental sensitivity we can imagine today!

Standard model lepton EDMs


Fourth order electroweak,


… + new physics? Much greater sensitivity to new, CP-violating physics!

Completely negligible at any experimental sensitivity we can imagine today!

Standard model lepton EDMs

Expect from SM,approximately:

de ≤ 10-38 e•cmd≤ 10-36 e•cmd ≤ 10-35 e•cm

Experimentally so far:

de< 2 x 10-27 e•cmd< 2 x 10-19 e•cmd< 3 x 10-17 e•cm

10-27 10-27

10-2810-28

exclu

ded

exclu

ded

excluded

excluded


The historyof neutron

EDM limits

10-26

10-20 10-20

10-26

1950 2000

ED

M u

pper

lim

it [e

cm

]

Smith, Purcell, Ramsey PR108(1957)120

[e cm]

.

Electro-weak standard modelexpectation: ~10-32 e•cm

RAL-Sussex-ILL dn < 2.9 x 10–26 e cmC.A.Baker et al., PRL 97 (2006) 131801


10-26

10-20

1950 2000

ED

M u

pper

lim

it [e

cm

]

[e cm]The strong CP problem

.

dn ≈ 10-16 e cm • QCD

QCD < 10-10~

LQCD ≈ LQCD + g2/(322) QCDGGQCD=0 ~

Why is QCD so small ?

QC

D


The SUSY CP problem

.

10-26

10-20

1950 2000

ED

M u

pper

lim

it [e

cm

]

[e cm]

dn ≈ 10-23 e cm ( )sinSUSY

300 GeV/c

MSUSY

22

SU

SY

Why is SUSY so small ?

Pospelov, Ritz, Ann. Phys. 318(2005)119 for MSUSY = 500GeV, tan = 3

(for neutron and electron!)


The state of the art …Class EDM Exp. bound [ecm] Reference

bare lepton < 1.8 x 10-19 PRD80(2009)052008

nucleon n < 2.9 x 10-26 PRL97(2006)131801

diamagnetic 199Hg < 3.1 x 10-29 PRL102(2009)101601

paramagnetic 205Tl < 9 x 10-25 PRL88(2002)071805


… and some comments:


bare lepton < 1.8 x 10-19 PRD80(2009)052008

nucleon n < 2.9 x 10-26 PRL97(2006)131801





enhancementfactor smaller limit weaker

with additional assumption concerning eN interaction

The state of the art …

205Tl is not the most precise EDM experiment, but

Class EDM Exp. bound [ecm] Reference

bare lepton < 1.8 x 10-19 PRD80(2009)052008

nucleon n < 2.9 x 10-26 PRL97(2006)131801





suppression of order 103

The state of the art …

199Hg is the most precise EDM experiment by 3 orders, but

Class EDM Exp. bound [ecm] Reference

bare lepton < 1.8 x 10-19 PRD80(2009)052008

nucleon n < 2.9 x 10-26 PRL97(2006)131801






bare lepton < 1.8 x 10-19 PRD80(2009)052008

nucleon n < 2.9 x 10-26 PRL97(2006)131801



The muon entry is the only one measured with charged particles.The experiment was performed in a storage ring, the techniquecould be considerably improved in the future. It also serves as a demonstration for storage ring EDMs that are planned withprotons (BNL) and deuterons (COSY) and may be other ions.




bare lepton < 1.8 x 10-19 PRD80(2009)052008

nucleon n < 2.9 x 10-26 PRL97(2006)131801



The neutron remains the classic example and is being pushed forward today by at least 4 international collaborations with somewhat different approaches. A future combination with resultsfrom proton and deuteron would allow to disentangle a possible QCD contribution to the nucleon EDMs.


MolecularYbF beam (Imperial) World-leading result in preparation. 1×10-29 e cm over 5 yrs.PbO* cell (Yale) Ending because of systematic errors.ThO beam (Harvard/Yale) “5 yrs from 1st result aiming at 10-29 e cm”PbF beam (Oklahoma) Just starting - “10 years from measurement”HfO+ (Boulder) trap “Serious measurement far away”. Might reach 1×10-29 e cmWC (Michigan)

AtomicThallium beam (Berkeley) Current world limit, but has gone as far as possible.Ultracold Cs in a lattice (Penn State). Probably 10 years from measurement.

Solid stateSpins in ferroelectric solids (Yale, Amherst, Indiana) Macroscopic sample. Low noise. Previous solid experiments had huge systematics, potential accuracy unknown.

Leading alternative approaches to eEDM

Courtesy: Ben Sauer


IonsProton storage ring (Brookhaven) R&D ongoing Deuteron storage ring (FZ Jülich) R&D ongoingOther ion EDMs in storage rings possible, and similarly muons (JPARC, PSI)

Atoms199Hg (Seattle) World-leading result: 3×10-29 e cm, next improvement: factor ~ 5.129Xe (Princeton, Munich) R&D ongoing213,225Ra (Argonne, Groningen) R&D ongoingRn (Triumf)

Leading alt. approaches to nuclear EDMs

Courtesy: Ben Sauer

NeutronsSussex-RAL-ILL World-leading result: 3×10-26 e cm, apparatus was moved to PSIPNPI-ILL: towards 10-26 e cm in 2012nEDM collaboration at PSI: ~ 5 x 10-27 e cm in 2012n2EDM (collaboration see nedm.web.psi.ch): 5 x 10-28 e cm in 2016Sussex-RAL-ILL-Oxford-Kuore (at ILL): similar time scale as n2EDMUS collaboration at SNS: 8 x 10-28 e cm after 2020Developments at JPARC, TRIUMF, and maybe other places

The Neutron EDM Collaboration

nedm.web.psi.ch

http://www.kuleuven.be/kuleuven/


Beam dump

nEDMn

• Source commissioning started fall 2009• Expect 1000 UCN/cm3 in typical experiments

(compare to currently 10 UCN/cm3 at ILL)• nEDM setting up since middle of 2009

PSI UCN Source


Present best limit: dn < 2.9 x 10-26 ecm

Sussex-RAL-ILL collaborationC. A. Baker et al., PRL 97 (2006) 131801

nEDM collaboration nedm.web.psi.ch15 groups, 50 people

Moved from ILL to PSI March 2009

Data taking at PSI 2010 – 2012 .. (Phase II)Sensitivity goal: 5x10-27ecm (95% C.L.)

Operation of new n2EDM apparatus 2012 – 2016 .. (Phase III)

Sensitivity goal: 5x10-28ecm (95% C.L.)


Please mark your calendars for the

2nd International Workshop on the

Physics of fundamental Symmetries and

Interactions – PSI2010 October 11-14, 2010 at the Paul Scherrer Institut, CHThe focus is on physics at the low energy, high precision frontier and related topics.psi2010.web.psi.ch


Conclusions

Thank you !


How to measure the neutron(or other) electric dipole moment ?

B E

h= 2 (μB+dn E)h = 2 (μB- dnE)

h = 4 dn E


Thallium edm

Thallium-EDM experiment


199Hg EDMOptically pumped 199Hg atoms precess in B & E fields, modulating absorption signal. Multiple cells remove effects of B drift.

Result: d(199Hg) < 3 x 10-29 e cm PRL 102 (2009) 101601

Provides good limit on CPv effects in nuclear forces, inc. QCD

“Confirms” dn<6x10-26 ecm.


Present nEDM limit

C. A. Baker et al., PRL 97 (2006) 131801P. G. Harris et al., PRL 82 (1999) 904

Sussex-RAL-ILL experiment

dn < 2.9 x 10-26 e cm (90%CL)


Special feature: co-magnetometer

·· · · · · ·

· ·· · ··· ··· ·· · ··

·· ·

BoEUCN

199Hg

K.Green et al., NIM A 404 (1998) 381 P. G. Harris et al., PRL 82 (1999) 904

199Hg co-magnetometer

50 pT


Next generation of experiments will …

… perhaps establish a finite value !!

Courtesy: A. Knecht

… in any case, severely constrain non-SM physics


Summary of leading nEDM exptsGroup # people Anticipated

sensitivity (ecm)

By...

UK: CryoEDM ~25 ~3E-27 2012

CryoEDM (new beamline)

~30?* ~3E-28 2016?

SNS-EDM ~90 <1E-28? >2020

nEDM@PSI ~50 ~5E-27~5E-28

20122016?

PNPI/ILL ~10-20? ~1E-26 2012?

Courtesy: Phil Harris – slightly modified

[email protected] 42Krakow, June 2010Paul Scherrer Institut Swiss Light Source (SLS)3. generation synchrotron

Proton accelerator: 600 MeV, 2.2 mA, 1.3 MW(upgrade program 3 mA)muons, pions and neutronsfor fundamental and appliedresearch

New UCN source

Proton therapy

New project:SwissFEL

Research on:• Energy• Nuclear safety• Structural biology, chemistry


3.6 m3 D2O

UCN~6000 cm-3

2 m3 volumestorage trap

~ 2000 cm-3exp> 1000 cm-3

The PSI UCN source

UCN guide

30 liters solid D2

vacuum

• high power (1.3 MW)• low duty cycle (1%) • multi-user capability

compare with typical 10 cm-3 at ILL

p-beam 1.3 MW


n[cm-2s-1]

Vc[dm3]

VUCN[dm3]

Tc[K]

Pc[W]

RUCN[cm-3s-1]

UCN[s]

UCN

[cm-3]

PSIspallation1% of 1.3MW

2.6 x 1013

pulsed (1%)30D2

2000 5 ~10Wavg.

3 x 105 10

400

1‘000in exp.

ILL

beam

1 x 1010

cw1-

1000.8 ~mW 30 100 1‘000

in exp.

FRM-IIreactor

4.5 x 1013

cw0.1D2

80 - 800

5 ~10W 5 x 105 30 3‘000dep vol

PNPIreactor

2 x 1012

cw35 100 -

4001.2 ~20W 4 x 103 30 10‘000

TRIUMFspallation25% of 20kW

2 x 1012

cw (25%)10 100 0.8 ~8W 4 x 103 150 50‘000

201

0≥2

010

≥201

2>

2013

My biased & personal summary table


Storage ring EDMs

[email protected], june 2010 the search for permanent electric dipole moments klaus kirch...

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