09.08.2011, providence ri paul scherrer institut philipp schmidt-wellenburg on behalf of the nedm...
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09.08.2011, Providence RI
Paul Scherrer InstitutPhilipp Schmidt-Wellenburg on behalf of the nEDM collaboration
An improved search of the nEDM
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 2/23
Baryon Asymmetry of the Universe
Sakharov criteria1. Baryon number
violation
2. C and CP violation
3. Thermal non-equilibrium
vs.
SM expectation:
1810~
n
nn BB
Observed*:
1010~
nBnnB
*WMAP
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 3/23
T
CP violation and EDM
→ CP violation so far only in weak decays
→ Might help explain BAU matter/anti-matter problem
→ Excellent probe for physics beyond the Standard Model (complementary to LHC)
A nonzero particle EDM violates P, T and, assuming CPT conservation, also CP.
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 4/23
Standard Model: CP violation
• QCD vacuum:
• Phase of CKM matrix:
aas GG
8
QCDeff LL
BE
ii
ii
ub
eccsscesccscss
ecssccessccccs
sscsc
VVV
VVV
VVV
323213232121
323213232121
31311
tbtstd
cbcscd
usud
Known from neutral K and B meson decays
dn≈ θ×10-15 e·cm → θ ≈ 10-10
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 5/23
nEDM from CKM Matrix
• No tree level contribution• No first loop contribution• No pure week interaction two
loop contribution• Only gluon two loop contribution
→ strongly suppressed
CP odd vertex
Standard Model nEDM:10-30 e·cm > dn >10-32 e·cm
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 6/23
+
< 1μm
A brief history of nEDM searches
1950 1960 1970 1980 1990 2000 2010 202010-32
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
Ne
utr
on
ED
M U
pp
er
Lim
it [e
cm]
Year of Publication
Supersymmetry predictions
RAL-Sussex-ILLdn < 2.9 x 10–26 e cmC.A.Baker et al., PRL 97 (2006) 131801
Smith, Purcell, Ramseydn < 5 x 10–20 e cmPR 108 (1957) 120
First Last
~ 50 years
Aimed at sensitivities at PSI:
Intermediate: dn < 5 x 10-27 e cm (95% C.L.) Finale:dn < 5 x 10-28 e cm (95% C.L.)
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 7/23
The measurement technique
Measure the precession frequencies in a magnetic and electric field:
EdBμ nn 22
EdBμ nn 22
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 8/23
The measurement technique
Measure the difference of precession frequencies in parallel/anti-parallel fields:
BBμEEdΔ nn 22
for dn<10-26 ω/ω < 2×10-9
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 9/23
The Ramsey technique
Free precessionat ω L
Apply /2 spinflip pulse...
“Spin up” neutron...
Second /2 spinflip pulse.
The Ramsey technique of separated oscillating fields
B0↑
B0↑ + Brf
B0↑
B0↑ + Brf
tT
rfnBt
2
rfnBt
2
Ramsey resonance curve
Sensitivity:
Visibility of resonanceE Electric field strengthT Time of free precessionN Number of neutrons
NETd
2)(
n
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 10/23
Ultracold neutrons (UCN)
NT
dn
1
storable neutrons(UCN)
V
E. Fermi, 1946 , Ya. B. Zeldovich Sov. Phys. JETP 9, 1389 (1959)
storage properties arematerial dependent
neV 350 NbVF
350 neV ↔ 8 m/s ↔ 500 Å ↔ 3 mK
magnetic60 neV/T
magnetic60 neV/T
gravity102 neV/m
gravity102 neV/m
strongVF
strongVF
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 11/23
New UCN source @PSI
not yet at designed strength, ramping up
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 12/23
Apparatus
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 13/23
Apparatus
5T Magnetto spin polarize UCNs
Switchto distribute the UCNs todifferent parts of the apparatus
Spin analyzer
Neutron detector
Precession chamberwhere neutrons precesses
Vacuum chamber
Magnetic field coilsB0-correction coils
Electrode (upper)
High voltage lead
E B
E~12 kV/cm
B=1 T
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 14/23
Measuring frequencies with UCN
Sensitivity:NET
d
2
)(n
• changing polarity every ~ 1.5h • comparing frequency +/- polarity• aimed at sensitivity ω 60 nHz
1.5
mHz
Ramsey resonance curve
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 15/23
The measurement technique
Measure the difference of precession frequencies in parallel/anti-parallel fields:
BBμEEdΔ nn 22
Active Stabilization and insitu field monitoring
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 16/23
Mercury co-magnetometer
¼ wave platelinear polarizer
Hg lamps
PM
polarization cell
HgO source
B0 ≈
1μ
T
• Average magnetic field (volume and cycle)
• σ(B) ~ 20 – 50 fT• Center of mass
different than UCN• Important Systematic effects
due to magnetic field gradients
τ = 140s
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 17/23
Corrected measurement
+ 12 Cesium magnetometers for field gradient measurements
50 p
T
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 18/23
Cesium magnetometers
Monitoring of vertical magnetic gradients
• Two cesium magnetometer arrays
• Stabilized laser• PID phase locked DAQ
1 2 3 4
5 … 11 12
±140kV
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 19/23
Systematic effects
EffectShift (see Ref.)
[10-27 e cm]σ (see Ref.) [10-27 e cm]
σ (at PSI) [10-27 e cm]
Door 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
vE translational 0.0 0.03 0.03
vE rotational 0.0 1.00 0.10
Second-order vE 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 0.10ac fields 0.0 0.01 0.01Total -3.8 7.19 1.37
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 20/23
Uncompensated field drift
GhE
d nn
2
Magnetization through changing polarity
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 21/23
Uncompensated field drift
Ramping speed = 1 kV/sCharging current = 35 nA
+100
-100
E [kV]
time
100 s
400-500 s
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 22/23
No effect is observed at the level of 2.8 fT/cm
No effect is observed at the level of 2.8 fT/cm
Translates into
Uncompensated field drift
cm 101615 27false
n ed
Dedicated runs (daytime)
cm false
n e27109.0d
Philipp Schmidt-Wellenburg APS DPF Meeting, Brown University Providence RI, 9th August 2011 23/23
Conclusion • UCN source is ramping up
→ first data this year (50 nights)• Reduction of main systematic effects
• Further improvements on systematic effects winter shut-down 2011-2012
• 200 nights of data in 2012-2013
cm sysstat e2710)46?(nd
cm 10)2 2 ? ( 27
sysstat end
09.08.2011, Providence RI
Paul Scherrer InstitutPhilipp Schmidt-Wellenburg on behalf of the nEDM collaborationalso at: 1Paul Scherrer Institut, 2PNPI Gatchina, 3Eidgenössische Technische Hochschule
The Neutron EDM Collaboration
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. Afach, G. Bison
N. Severijns, R. Chankova, S. Roccia
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. Franke3, M. Horras3, 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
09.08.2011, Providence RI
Paul Scherrer InstitutPhilipp Schmidt-Wellenburg on behalf of the nEDM collaboration
Thank you