The Berkeley Update:
Atomic-Physics Tests
of Fundamental Symmetries
Parity Violation and Testing Bose Statistics
Dmitry Budker
University of California, Berkeley
Nuclear Science Division, LBNL
Cairns
July 25, 2010
http://budker.berkeley.edu/
Outline
1. Measurement of atomic P in Yb
2. Testing for Bose-statistics violation
in Ba 2γ transitions
Atomic PV (a.k.a. PNC) landmarks
• 1959 Ya. B. Zel’dovich:
PNC (Neutr. Current)  Opt. Rotation in atoms
• 1974 M.-A. & C. Bouchiat
Z3 enhancement  PV observable in heavy atoms
• 1978-9 Novosibirsk, Berkeley
discovery of PV in OR(Bi) and Stark-interf.(Tl)
PV measured to 1-2% in Cs, Tl, Bi, Pb
• 1997 Boulder
0.35% measurement, discovery of anapole moment
• 2009 Berkeley Large APV in Yb (personal landmark)
26 years
•…1995 Boulder, Oxford, Seattle, Paris
What were we doing all this time?
• 1983-1988 Bi, diatomic molecules, Sm
(Novosibirsk) with L. M. Barkov and M. Zolotorev
• 1989-1994 Tl
(Berkeley) with E. D. Commins, D. DeMille, and M. Zolotorev
• 1989-
Dy
M. Zolotorev, D. DeMille, E. D. Commins, A.-T.Nguyen,
A. Cingoz, N. Leefer
• 1995-1997 Sm
S. M. Rochester
• 1995-
Yb
S. J. Freedman, D. DeMille, C. J. Bowers, G. Gwinner, J. E. Stalnaker,
D. F. Kimball, V. V. Yashchuk, K. Tsigutkin, A. Family, D. DounasFrazer,…
Why did it take so long to detect
PNC?
Dr. A.-T. Nguyen says: it was deposited
Parity Violation in Yb: motivation
Atomic Physics:
 Verification of large predicted atomic PV effect
(x100 Cs; DeMille, Kozlov et al, Das et al)
Nuclear Physics:
 Nuclear spin-dependent PV – anapole moments
(valence neutrons)
 Isotopic ratios and neutron distributions
(7 stable isotopes; N=8)
6
Anapole Moment
of a current distribution (e.g., a nucleus)
Ya. B. Zel’dovich
 
  1
j (r ) 3
AR     d r
c | Rr |

1
1 
1
1
1
      k rk    k  l rk rk  ...
R
2
R
| Rr | R 
 (0) 
1   3
A R 
j (r ) d r  0

cR


 (1)  m  R  1    3
A R 
;m
r  j (r )d r
3

R
2c
 ( 2)   
  3

2
A R  a ( R ); a    r j (r )d r



T-conserving; P-violating
Atomic Yb: energy levels and transitions
+5d6p
PV amplitude: 10-9e·a0
DeMille (1995)
|M1|10-4 μB
J.E. Stalnaker, et al, PRA
66(3), 31403 (2002)
β2·10-8 ea0/(V/cm)
C.J. Bowers et al, PRA 59(5), 3513
(1999); J.E. Stalnaker et al, PRA 73,
043416 (2006)
8
Stark-PV-interference technique
(invented by the Bouchiats in 1970s)
The Yb PV Experiment
Electric and magnetic fields define handedness


Rotational Invariant:   B E    B

10
Reversals and pseudo-reversals
• E-field reversal (14 ms: 70-Hz modulation)
• Lineshape scan (200 ms/point x 100 pts/lineshape = 40 s)
• B-field reversal (every few minutes)
• Polarization angle (occasionally)
• E-field magnitude
• B-field magnitude
• Angle magnitude
11
Yb PV Amplitude: Results
150
Theoretical prediction
Mean value
68% confidence band
z/b (mV/cm)
100
50
0
-50
0
2
4
6
8
10
12
14
16
18
20
Run number
z/b=39(4)stat.(5)syst. mV/cm  |z|=(8.7±1.4)×10-10 ea0
Accuracy is affected by HV-amplifier noise, fluctuations of
stray fields, and laser drifts → improved for the next phase
Progress in Yb APV
Completed Work







Lifetime Measurements
General Spectroscopy (hyperfine shifts, isotope shifts)
dc Stark Shift Measurements
Stark-Induced Amplitude (β): 2 independent measurements
M1 Measurement (Stark-M1 interference)
ac Stark Shift Measurements
Verification of APV enhancement
Near Future…
 Verification of expected isotopic dependence
 PV in odd isotopes: NSD PV, Anapole Moment
 PV in a string of isotopes; neutron distributions, …
Further Ahead (?)
 Testing the Standard Model [Brown et al PHYSICAL REVIEW C 79, 035501 (2009)]
K. Tsigutkin
post-doc
A. Family
undergrad
D. Dounas-Frazer
grad.student
14
V. V. Yashchuk
S. J. Freedman
J. E. Stalnaker
2. The Ba 2γ experiment:
Damon English
BES  violation
The degenerate two-photon transition
selection rule
2
1
1
MJ=-1
2
MJ=0
Destructive
interference of two
quantum paths
MJ=1
S. N.
Bose
1999
DeMille 1
The Berkeley Experiment
Animated version: YouTube: Test of Bose-Einstein statistics for photons
Results
  4.0 10
11
90% c.l.
Results
Splitting effect
Mixing Effect
Outline
1. Measurement of atomic P in Yb
2. Testing for Bose-statistics violation
in Ba 2γ transitions
Yb PNC signature
23