1. X-ray telescope: D. Greenwald, R. Kotthaus, G. Lutz
CAST
(CERN Axion Solar Telescope)
Search for Solar Axions
The CAST Collaboration
Athens, CERN, Chicago, Darmstadt, Frankfurt, Freiburg,
Moscow (INR), Munich (MPE-MPP), Pisa, Saclay,
South Carolina, Thessaloniki, Zagreb, Zaragoza
X-ray telescope: D. Greenwald, R. Kotthaus, G. Lutz
Axion and solar physics: G. Raffelt, P. Serpico

2. Motivation to search for the AXION
solve the „Strong CP Problem“
(„Peccei-Quinn“ Axion)
find a DARK MATTER candidate
(„invisible“ Axion)

3. The „invisible“ Axion CAST „hot“ „cold“ DM 2005, ... 2003, 2004
Bradley et al.:
Rev. Mod. Phys. 75 (2003)
Hannestad, Mirizzi, Raffelt:
J. Cosm. Astropart. Physics
Vol. 07 (2005)
„hot“
„cold“ DM
2005, ...
2003, 2004
CAST

4. Ng ~ gag4 Solar axions axions X ray „HELIOSCOPE“
SOLAR AXION PRODUCTION
Ng ~ gag4
axions
Transverse magnetic field (B)
X ray
detector
AXION PHOTON CONVERSION L
„HELIOSCOPE“

5. Solar axion production
Thermal photon-nucleus interaction in the Sun core (T~15.6x106K)
g + Ze a+ Ze g a Ze
axion energy
Raffelt,
Serpico
(2005)
solar radius
Solar axion differential flux on Earth
for gagg = GeV-1

6. Energy-momentum conservation: Axion-photon conversion probability:
Axion detection
Axion – photon conversion in a transverse magnetic field B ( ampl. ~ E.B )
a + magnet g + magnet a g
Energy-momentum conservation:
magnet
(q = momentum transfer to magnet)
(mg: effective photon mass in dispersive medium)
Axion-photon conversion probability:
(B = magnetic field component
transverse to axion momentum)
CAST phase I:
ma< O (10-2eV)
qL << 1

7. CAST Helioscope Axion sensitivity enhanced by > 103
LHC prototype dipole magnet
B = 9.0 Tesla
L = 9.26 m
Wolter I
X-ray mirror
(ABRIXAS)
X-ray Telescope
Axion sensitivity
enhanced by
> 103
pn-CCD (XMM-Newton)

8. X-ray mirror
focus,
pn-CCD

9. Telescope alignment signal/background improvement: x 200 Laser spot
X-ray beam
defines axion signal area
1 cm
3 cm
signal/background improvement: x 200
signal and background simultaneously
reference to monitor
stability of focus

10. pn-CCD background 2004 background energy spectrum axion search region
(1 – 7 keV):
(7.69 +_ 0.07) x 10-5
events cm-2 sec-1 keV-1
axion region
M. Kuster et al.: SPIE 2005,
physics/
R.K. et al.: NSS-MIC 2005,
astro-ph/

12. The „invisible“ Axion
gag < GeV-1 (95% CL) Phys. Rev. Lett. 94, (2005)

13. CCD photon counts in solar axion search region

14. The „invisible“ Axion
He (phaseII)
vacuum (phase I)
gag < GeV-1 (95% CL) Phys. Rev. Lett. 94, (2005)

15. Extending a-g coherence to higher ma values
Fill the magnetic channels with Helium gas mg > 0
coherence: qL <<1
Ne: number of electrons/cm3
r: gas density (g/cm3) eV
< 0.2x10-3 g/cm3 (He4 vapour pressure at 1.8°K) mg ~ 0.26 eV

16. Start Phase II: Nov. 23, 2005

17. CAST Phase II: He cold windows

18. Thermo-acoustical He Pressure Oscillations
damping

19. ma=0.14 eV

20. 2005/6 ~ 170 pressure settings 4He (0 – 14mbar)
Vacuum
Phase I
Phase II
4He He
2005/6 ~ 170 pressure settings 4He (0 – 14mbar)
2006/7 ~ 700 for 3He (14-60 mbar)
Phase II:

21. H. Davoudiasl and P. Huber, hep-ph/0509293
1 m2
ma< 10-4 eV
gag ~ GeV-1

22. H. Davoudiasl and P. Huber, hep-ph/0509293
1 m2
ma< 10-4 eV
gag ~ GeV-1

23. PVLAS
CAST prospects

24. rotation of linear polarization:
PVLAS Experiment
(Zavattini et al., hep-ex/ )
rotation of linear polarization:
(3.9 +_ 0.5) rad/pass
Letter of Intent to CERN: L. Duvillaret et al., CERN-SPSC
Plan at DESY: TTF (X-FEL) into string of HERA dipole magnets

25. “Shining light through walls”
K. van Bibber
et al., 1987
A. Ringwald, 2003
P. Pugnat et al., 2005
LoI: CERN-SPSC
R. Rabadan,
A. Ringwald and
C. Sigurdson, 2005
TTF (XFEL) + HERA magnets a x x