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Axion Searches

Axion Searches. Sikivie (IAS, UF) Joint ILIAS-CAST-CERN Axion Training C.E.R.N. November 30, 2005. Outline. Introduction Axion cosmology Dark matter axion detection Solar axion detection Laser experiments Other methods. The Strong CP Problem.

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Axion Searches

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  1. Axion Searches Sikivie (IAS, UF) Joint ILIAS-CAST-CERN Axion Training C.E.R.N. November 30, 2005

  2. Outline Introduction Axion cosmology Dark matter axion detection Solar axion detection Laser experiments Other methods

  3. The Strong CP Problem Because the strong interactions conserve P and CP,. The Standard Model does not provide a reason for to be so tiny, but a relatively small modification of the model does provide a reason …

  4. If a symmetry is assumed, relaxes to zero, and a light neutral pseudoscalar particle is predicted: the axion.

  5. f f a a = 0.97 in KSVZ model 0.36 in DFSZ model

  6. The remaining axion window laboratory searches cosmology stellar evolution

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

  8. Thermal axions g a q these processes imply an axion decoupling temperature E. Masso R. Rota G. Zsembinszki thermal axion temperature today: = effective number of thermal degrees of freedom at axion decoupling

  9. Cold Axions Density Velocity dispersion Effective temperature

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

  11. Axion production by vacuum realignment V V a a initial misalignment angle

  12. String loop decaying into axion radiation simulation by S. Chang, C. Hagmann and PSsee also: R. Battye and P. Shellard;M. Yamaguchi, M.Kawasaki and J. Yokoyama

  13. Domain wall bounded by string decaying into axion radiation

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

  15. . If no inflation after the PQ phase transition . cold axions are produced by vacuum realignment, string decay and wall decay axion miniclusters appear (Hogan and Rees, Kolb and Tkachev)

  16. introduce require for stellar evolution D.B. Kaplan and K.M. Zurek (hep-ph/0507236) for cosmological energy density arrange allows much larger than GeV

  17. Axion dark matter is detectable a X FFT A/D

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

  19. Axion Dark Matter eXperiment

  20. High resolution analysis of the signal may reveal fine structure …

  21. The cold dark matter particles lie on a 3-dimensional sheet in 6-dimensional phase space . z the physical density is the projection of the phase space sheet onto position space z

  22. The cold dark matter particles lie on a 3-dimensional sheet in 6-dimensional phase space . z the physical density is the projection of the phase space sheet onto position space z

  23. Implications: At every point in physical space, the distribution of velocities is discrete, each velocity corresponding to a particular flow at that location. 2. At some locations in physical space, where the number of flows changes, there is a caustic, i.e. the density of dark matter is very high there.

  24. Phase space structure of spherically symmetric halos

  25. (from Binney and Tremaine’sbook)

  26. The flow of cold collisionless particles from all directions in and out of a region necessarily forms a caustic (Arvind Natarajan and PS, astro-ph/0510743). Hence galactic halos have inner caustics as well as outer caustics. If the initial velocity field is dominated by net overall rotation, the inner caustic is a ‘tricusp ring’. If the initial velocity field is irrotational, the inner caustic has a ‘tent-like’ structure.

  27. simulation by Arvind Natarajan

  28. The caustic ring cross-section D -4 an elliptic umbilic catastrophe

  29. The Big Flow • density • velocity • velocity dispersion previous estimates of the total local halo density range from 0.5 to 0.75 10 gr/cm -24 3 in the direction of galactic rotation in the direction away from the galactic center

  30. Experimental implications • for dark matter axion searches - peaks in the energy spectrum of microwave photons from conversion in the cavity detector - high resolution analysis of the signal yields a more sensitive search (with L. Duffy and ADMX collab.) • for dark matter WIMP searches - plateaux in the recoil energy spectrum from elastic WIMP collisions with target nuclei - the flux is largest around December (Vergados; Green; Gelmini and Gondolo; Ling, Wick &PS)

  31. High resolution analysis of the signal may reveal fine structure …

  32. an environmental peak, as seen in the medium and high resolution channels

  33. ADMX limit using high resolution (HR) channel for

  34. Axion to photon conversion in a magnetic field a x 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 in vacuum probability with

  35. CernAxionSolarTelescope Sunset Photon detectors Sunrise Photon detectors Sunrise axions Sunset axions Decommissioned LCH test magnet Rotating platform 3 X-ray detectors X-ray Focusing Device

  36. 4He3He 2005 ~ 100 pressure settings 4He (0 – 6mbar) 2006/7 ~ 700 for 3He (6-60 mbar) Vacuum Phase I Phase II

  37. Detecting solar axions using Earth’s magnetic field Earth Sun by H. Davoudiasl and P. Huber hep-ph/0509293 For axion masses , a low-Earth-orbit x-ray detector with an effective area of , pointed at the solar core, can probe down to , in one year.

  38. Linearly polarized light in a constant magnetic field

  39. Rotation

  40. Rotation and Ellipticity

  41. Experimental observation of optical rotation generated in vacuum by a magnetic field by E. Zavattini et al. (the PVLAS collaboration) hep-ex/0507107 the average measured optical rotation is (3.9 0.5) 10 rad/pass through a 5 T, 1 m long magnet -12

  42. PVLAS

  43. The PVLAS result can be interpreted in terms of an axion-like particle b inconsistent with solar axion searches, stellar evolution descrepancy may be avoided in some models E. Masso and J. Redondo, hep-ph/0504202

  44. 4He3He 2005 ~ 100 pressure settings 4He (0 – 6mbar) 2006/7 ~ 700 for 3He (6-60 mbar) Vacuum Phase I Phase II

  45. Shining light through walls a K. van Bibber et al. ‘87 A. Ringwald ‘03 P. Pugnat et al. ‘05 R. Rabadan, A. Ringwald and C. Sigurdson ‘05 x x rate

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

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