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The neutron Electric Dipole Moment experiment exploring the low-energy precision frontier Geza Zsigmond on behalf of the nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 1 G Zsigmond - nEDM Collaboration

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 1

The neutron Electric Dipole Moment experiment  exploring the low-energy precision frontier

Geza Zsigmond on behalf of the nEDM Collaboration

Europhysics Conference on HEP, Grenoble, July 21-27 2011

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 2

The Neutron EDM Collaboration

also at: 1Paul Scherrer Institut, 2PNPI Gatchina, 3Eidgenössische Technische Hochschule, 4TU München

  • M. Burghoff, S. Knappe-Grüneberg, A. Schnabel, L. Trahms, J. Vogt
  • G. Ban, Th. Lefort, Y. Lemiere, O. Naviliat-Cuncic,
  • E. Pierre1, G. Quéméner
  • K. Bodek, St. Kistryn, G. Wyszynski, J. Zejma
  • A. Kozela
  • N. Khomutov
  • M. Kasprzak, P. Knowles, A. Weis, Z. Grujic
  • G. Pignol, D. Rebreyend, S. Roccia
  • S. Afach, G. Bison
  • N. Severijns
  • C. Plonka-Spehr, J. Zenner1
  • W. Heil, H.C. Koch, A. Kraft, T. Lauer , D. Neumann, Yu. Sobolev2
  • Z. Chowdhuri, M. Daum, M. Fertl3 , B. Franke4, M. Horras4,
  • B. Lauss, J. Krempel, A. Mtchedlishvili, P. Schmidt-Wellenburg,
  • G. Zsigmond
  • C. Grab, K. Kirch1, C. Kittel, A. Knecht, F. Piegsa

Physikalisch Technische Bundesanstalt, Berlin Laboratoire de Physique Corpusculaire, Caen Institute of Physics, Jagiellonian University, Cracow Henryk Niedwodniczanski Inst. Of Nucl. Physics, Cracow Joint Institute of Nuclear Reasearch, Dubna Département de physique, Université de Fribourg, Fribourg Laboratoire de Physique Subatomique et de Cosmologie, Grenoble Biomagnetisches Zentrum, Jena Katholieke Universiteit, Leuven

  • Inst. für Kernchemie, Johannes-Gutenberg-Universität, Mainz
  • Inst. für Physik, Johannes-Gutenberg-Universität, Mainz

Paul Scherrer Institut, Villigen Eidgenössische Technische Hochschule, Zürich

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 3

T

EDM a probe for CP violation

E σ σ B σ σ d H    

 

E σ σ B σ σ        d H 

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 4

T

EDM a probe for CP violation

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

E σ σ B σ σ d H    

 

E σ σ B σ σ        d H 

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 5

T

EDM a probe for CP violation

→CP violation might help to explain matter/anti-matter asymmetry (BAU) → Excellent probe for physics beyond the Standard Model A nonzero particle EDM violates T, P and, assuming CPT conservation, also CP.

E σ σ B σ σ d H    

 

E σ σ B σ σ        d H 

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 6

Previous neutron EDM searches

1950 1960 1970 1980 1990 2000 2010 2020 10

  • 32

10

  • 31

10

  • 28

10

  • 27

10

  • 26

10

  • 25

10

  • 24

10

  • 23

10

  • 22

10

  • 21

10

  • 20

10

  • 19

Standardmodel calculations

ORNL, Harvard MIT, BNL LNPI Sussex, RAL, ILL

Neutron EDM Upper Limit [ecm] Year of Publication Supersymmetry predictions

Sussex-RAL-ILL |dn | < 2.9 x 10–26 e cm (90% C.L.)

C.A.Baker et al., PRL 97 (2006) 131801

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 7

Previous neutron EDM searches

1950 1960 1970 1980 1990 2000 2010 2020 10

  • 32

10

  • 31

10

  • 28

10

  • 27

10

  • 26

10

  • 25

10

  • 24

10

  • 23

10

  • 22

10

  • 21

10

  • 20

10

  • 19

Standardmodel calculations

ORNL, Harvard MIT, BNL LNPI Sussex, RAL, ILL

Neutron EDM Upper Limit [ecm] Year of Publication Supersymmetry predictions

Sussex-RAL-ILL |dn | < 2.9 x 10–26 e cm (90% C.L.)

C.A.Baker et al., PRL 97 (2006) 131801

Goal nEDM Collaboration at PSI: 2012-2013: |dn | < 5 x 10-27 e cm (95% C.L.) Final (n2EDM): |dn | < 5 x 10-28 e cm (95% C.L.)

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 8

n

  • Source commissioned end of 2010
  • Full proton beam

(590 MeV, 2.2 mA, 1% duty cycle e.g. 5s/500s)

nEDM

UCN beamlines at PSI

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 9

Experiment principle

Difference of UCN precession frequencies in parallel/anti-parallel B and E fields:

   

   

    B B μ E E d hΔ

n n

2 2 

for dn <10-26 e cm  < 60 nHz at 30 Hz

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 10

Experiment principle

Difference of UCN precession frequencies in parallel/anti-parallel B and E fields:

   

   

    B B μ E E d hΔ

n n

2 2 

for dn <10-26 e cm  < 60 nHz at 30 Hz

New: Improved magnetometry 

199Hg + Cs magnetometers

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 11

Apparatus – main parts

5T magnet

to spin polarize UCNs

UCN switch Spin analyzer Neutron detector Precession chamber Mu-metal shields Magnetic field coils

B0

  • correction coils

Electrode (upper) High voltage lead

E E~12 kV/cm B B=1 T

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 12

The Ramsey technique

Free precession at ω L Apply /2 spin flip pulse... “Spin up” neutron... Second /2 spin flip pulse.

  • f separated oscillatory fields

B0↑ B0↑ + Brf B0↑ B0↑ + Brf

t T 

rf nB

t   2 

rf nB

t   2 

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 13

The Ramsey technique

Free precession at ω L Apply /2 spin flip pulse... “Spin up” neutron... Second /2 spin flip pulse.

  • f separated oscillatory fields

B0↑ B0↑ + Brf B0↑ B0↑ + Brf

t T 

rf nB

t   2 

rf nB

t   2 

Ramsey resonance curve Sensitivity:  Visibility of resonance E Electric field strength T Time of free precession N Number of neutrons

N ET d   2 ) (

n

 

Ramsey resonance curve

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 14

The Ramsey technique

Free precession at ω L Apply /2 spin flip pulse... “Spin up” neutron... Second /2 spin flip pulse.

  • f separated oscillatory fields

B0↑ B0↑ + Brf B0↑ B0↑ + Brf

t T 

rf nB

t   2 

rf nB

t   2 

Ramsey resonance curve Sensitivity:  Visibility of resonance E Electric field strength T Time of free precession N Number of neutrons

N ET d   2 ) (

n

 

Ramsey resonance curve

25x more at PSI

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 15

nEDM systematic effects

Effect Shift (Bak06) [10-27 e cm] σ (Bak06) [10-27 e cm] σ (goal at PSI) [10-27 e cm] Cavity dipole

  • 5.6

2.00 0.10 Other dipole fields 0.0 6.00 0.40 Quadrupole difference

  • 1.3

2.00 0.60 vE translational 0.0 0.03 0.03 vE rotational 0.0 1.00 0.10 Second-order vE 0.0 0.02 0.02 Hg light shift (geo phase) 3.5 0.80 0.40 Hg light shift (direct) 0.0 0.20 0.20 Uncompensated B drift 0.0 2.40 0.90 Hg atom EDM

  • 0.4

0.30 0.06 Electric forces 0.0 0.40 0.40 Leakage currents 0.0 0.10 0.10 ac fields 0.0 0.01 0.01 Total

  • 3.8

7.2 1.4

  • C. A. Baker et al., Phys. Rev. Lett

97 (2006) 131801

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 16

Magnetic field stability

2×n ×(B) < 4×(dn )×E

N E T α d    2 ) ( 

n

PSI ILL

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 17

Prepared for data taking

Thermal stabilization Surrounding

  • mag. field

compensation 1

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 18

Prepared for data taking

Thermal stabilization Surrounding

  • mag. field

compensation 1 Superconducting magnet polarizer 2

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 19

Prepared for data taking

Thermal stabilization Surrounding

  • mag. field

compensation 1 Superconducting magnet polarizer 2 UCN precession chamber HV electrodes Mu-metal shields Cs-Magnetometers 3 4

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 20

Prepared for data taking

Thermal stabilization Surrounding

  • mag. field

compensation 1 Superconducting magnet polarizer 2 UCN precession chamber HV electrodes Mu-metal shields Cs-Magnetometers 3 4 High rate UCN detection system 5

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G Zsigmond - nEDM Collaboration Europhysics Conference on HEP, Grenoble, July 21-27 2011 21

Outlook 2011- 2013

UCN source at PSI commissioned 2010 25× more UCN/cycle than at ILL Main systematic effects reduced by improved magnetometry First nEDM data this year (50 nights)

cm 10 ) 4 6 ? (

27 sys stat

    

 e

dn

cm 10 ) .4 1 3 ? (

27 sys stat

    

 e

dn

cm 10 ) 7 5 1 2 ( '06 al. et Baker

27 sys stat

     

 e

dn

Previous:

Further improvements on sys. effects in winter 2011-2012 when PSI accelerator shut-down In 2012-2013 – 200 nights of data taking