1. The Search for Axions Pierre Sikivie Axion Dark Matter Conference &
Oscar Klein Centre Colloquium
December 5, 2016

2. Outline Axion motivation and properties
Production in the early universe
Axion dark matter detection
Other methods

3. The Strong CP Problem where
The absence of P and CP violation in the strong interactions requires
from upper limit
on the neutron electric
dipole moment

4. A level pooltable on an inclined floorg

5. The Standard Model does not provide a
reason for to be so tiny,
but a relatively small modification does …

6. is a symmetry of the classical action is spontaneously broken
has a color anomaly
Peccei and Quinn, 1977

7. If a symmetry is assumed,
relaxes to zero,
and a light neutral pseudoscalar particle is predicted: the axion.
Weinberg, Wilczek 1978

8. A self adjusting pooltable
1 ton

9. f f a a
= in KSVZ model
in DFSZ model

10. Searching for the pooltable oscillation quantum
1 ton

11. Axions are constrained by
beam dump experiments
rare particle decays
radiative corrections
the evolution of stars

12. from G. Raffelt,

13. The remaining axion window
laboratory
searches
cosmology
stellar
evolution

14. Thermal axions g a q
these processes imply an axion decoupling temperature
thermal axion
temperature today:
= effective number of thermal degrees of freedom at axion decoupling

15. There are two cosmic axion populations: hot and cold.
When the axion mass turns on, at QCD time,

16. Effective potential V(T, )
axion strings
axion domain walls

17. Axion production by vacuum realignment
initial
misalignment
angle
J. Preskill, M. Wise & F. Wilczek, L. Abbott & PS, M. Dine & W. Fischler, 1983

18. A self adjusting pooltable
1 ton

19. If inflation after the PQ phase transition.
may be
accidentally
suppressed .
produces
isocurvature
density perturbations
CMBR constraint

20. If no inflation after the PQ phase transition.
cold axions are produced by vacuum realignment, string decay and wall decay .
S. Borsanyi et al.
axion miniclusters appear

21. Axions are cold dark matter
Density
Velocity dispersion
Effective temperature

22. Searching for relic pooltable oscillations
1 ton

23. Axion Search Techniques
the cavity haloscope
the axion helioscope
shining light through walls
axion mediated long-range forces
NMR methods
LC circuit
atomic transitions

24. Axion dark matter is detectable
PS '83 a X
A/D
FFT

26. conversion power on resonance
search rate for s/n = 4

27. Axion Dark Matter eXperiment

28. ADMX hardware
high Q cavity
experimental insert

29. ADMX in its second generation
*Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE-AC52-07NA27344, DE-AC03-76SF00098, NSF Grant PHY , and the Livermore LDRD program

30. Upgrade with SQUID AmplifiersIB
The basic SQUID amplifier is a flux-to-voltage transducer
SQUID noise arises from Nyquist noise in shunt resistance
scales linearly with T
However, SQUIDs of conventional design are poor amplifiers above 100 MHz (parasitic couplings). F
Vo (t)
Flux-bias to here

31. Quantum-limited SQUID-based amplification
SQUIDs have been measured with
TN ~ 50 mK
Compared to ~ 2 K for HFET amplifiers
Near quantum– limited noise
Provides a large increase in ADMX sensitivity
SQUID amplifiers
J. Clarke et al.

32. Will scan the lower-mass decade at or below DFSZ sensitivity
Gen 2 ADMX sensitivity
Will scan the lower-mass decade at or below DFSZ sensitivity

33. ADMX-HF at Yale
Multi-post system that consists of 3 rotors connected on common axis and 3 stators.
4” ID cavity: Six 0.5” diameter rods
Freq. span GHz

34. B. Brubaker et al., arXiv:

35. Center for Axion and Precision Physics (CAPP) in Korea

37. Axion Search Techniques
the cavity haloscope
the axion helioscope
shining light through walls
axion mediated long-range forces
NMR methods
LC circuit
atomic transitions

38. Axion to photon conversion in a magnetic field
Theory
P. S. ’83
L. Maiani, R. Petronzio
and E. Zavattini ’86
K. van Bibber et al. ’87
G. Raffelt and
L. Stodolsky, ‘88
K. van Bibber et al. ’89
Experiment
D. Lazarus et al. ’92
R. Cameron et al. ‘93
S. Moriyama et al. ’98,
Y. Inoue et al. ’02
K. Zioutas et al. 04
E. Zavattini et al. 05 x
conversion probability
with

39. Tokyo Axion Helioscope

40. Cern Axion Solar Telescope
Decommissioned LCH test magnet
Rotating platform
3 X-ray detectors
X-ray Focusing Device
Sunset
Photon detectors
Sunset axions
Sunrise axions
Sunrise

42. CAST Collaboration: Phys. Rev. Lett. 112 (2013) 091302

46. Primakoff conversion of solar axions in crystals on Earth
Solax, Cosme ’98 a Ge
DAMA ‘01 x
NaI (100 kg)
CDMS ‘09
few keV Ge
Bragg scattering on crystal lattice
Edelweiss ‘13 Ge

48. from C. Eleftheriadis (CAST), arXiv: 0706.0637

49. Axio-Electric Effect Theory Experiment F. Avignone et al., '87
S. Dimopoulos, G.D. Starkman & B.W. Lynn, '86
F. Avignone et al., '87
E. Aprile et al., '09
E. Armengaud et al. ‘13

50. Linearly polarized light in a constant magnetic field

51. Rotation

52. Rotation and Ellipticity
Maiani, Petronzio and Zavattini, 1986

53. PVLAS

54. Shining light through walls
K. van Bibber et al. ‘87
A. Ringwald ‘03
R. Rabadan,
A. Ringwald and
C. Sigurdson ‘05
P. Pugnat et al. '05
C. Robilliard et al. '07
A. Afanasev et al. '08
A. Chou et al. '08
K. Ehret et al. '10 a x x
rate

55. Limits from "light through wall" axion searches

57. Resonantly Enhanced Axion-Photon Regeneration
Wall
Photon
Detector a 
Laser L B0
Magnet
Matched Fabry-Perots IO
Laser
Magnet
Photon
Detectors
(b)
Hoogeveen (1996); P.S., Tanner and van Bibber (2007) & G. Mueller (2009)

59. Macroscopic forces mediated by axions
Theory:
J. Moody and
F. Wilczek ’84
Experiment:
A. Youdin et al. ’96
W.-T. Ni et al. ‘96
forces coupled to
the f spin density
forces coupled to
the f number density
background of
magnetic forces

60. NMR with long range axion field
A. Arvanitaki and A. Geraci, 2014 th
the rotating mass on
the left produces an
oscillating axion field
the oscillating axion field
is an effective magnetic
field in an NMR experiment

61. Axion Search Techniques
the cavity haloscope
solar axion searches
shining light through walls
NMR methods
axion mediated long-range forces
LC circuit
atomic transitions

62. NMR techniques
P. Graham, S. Rajendran; D. Budker, M. Ledbetter, A. Sushkov

63. the axion field induces an oscillating nuclear
electric dipole moment

66. Axion dark matter detection using an LC circuit
PS, D. Tanner and N. Sullivan, 2013
to re
circuit should be cooled to milli-Kelvin
temperatures

69. Wire array detector - pass currents through superconducting wires
PS, D. Tanner and Y. Wang, 1992
G. Rybka, A. Wagner et al. 2004
- pass currents through superconducting wires
- produce
- enhance the quality factor by placing the array in a
confocal resonator
- tune to

70. Dielectric Haloscope
A. Caldwell et al., arXiv

71. Dish antenna D. Homs, J. Jaeckel, A. Lindner,
A. Lobanov, J. Redondo & A. Ringwald, 2013
B. Doebrich et al. ,2014

72. Axion dark matter detection using atomic transitions
PS 2014
- tune using the Zeeman effect
- use laser techniques to count axion induced transitions
- must cool to milli-Kelvin temperatures

79. Conclusions Axions solve the strong CP problem
A population of cold axions is naturally produced in the early universe which may be the dark matter today
Axion dark matter is detectable