Probing eV-scale axions with CAST

Journal Article · Sun Feb 15 00:00:00 EST 2009 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2009/02/008· OSTI ID:22156893

Arik, E.; Boydag, F. S.; Cetin, S. A.; Dogan, O. B. ^[1]; Aune, S. ^[2]; Autiero, D.; Barth, K.; Borghi, S.; Davenport, M.; Lella, L. Di; Elias, N. ^[3]; Belov, A. ^[4]; Beltran, B.; Carmona, J. M.; Cebrian, S.; Dafni, T. ^[5]; Bourlis, G. ^[6]; Braeuninger, H. ^[7]; Collar, J. I. ^[8]; others, and

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1. Dogus University, Istanbul (Turkey)
2. CEA, IRFU, Centre de Saclay, Gif-sur-Yvette (France)
3. European Organization for Nuclear Research (CERN), Geneve (Switzerland)
4. Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow (Russian Federation)
5. Instituto de Fisica Nuclear y Altas Energias, Universidad de Zaragoza, Zaragoza (Spain)
6. Present address: Hellenic Open University, Patras (Greece)
7. Max-Planck-Institut fuer extraterrestrische Physik, Garching (Germany)
8. Enrico Fermi Institute and KICP, University of Chicago, Chicago, IL (United States)

We have searched for solar axions or other pseudoscalar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we previously have reported results from CAST with evacuated magnet bores (Phase I), setting limits on lower mass axions, here we report results from CAST where the magnet bores were filled with {sup 4}He gas (Phase II) of variable pressure. The introduction of gas generates a refractive photon mass m{sub {gamma}}, thereby achieving the maximum possible conversion rate for those axion masses m{sub a} that match m{sub {gamma}}. With 160 different pressure settings we have scanned m{sub a} up to about 0.4 eV, taking approximately 2 h of data for each setting. From the absence of excess x-rays when the magnet was pointing to the Sun, we set a typical upper limit on the axion-photon coupling of g{sub a{gamma}}{approx}<2.2 Multiplication-Sign 10{sup -10} GeV{sup -1} at 95% CL for m{sub a}{approx}<0.4 eV, the exact result depending on the pressure setting. The excluded parameter range covers realistic axion models with a Peccei-Quinn scale in the neighborhood of f{sub a} {approx} 10{sup 7} GeV. Currently in the second part of CAST Phase II, we are searching for axions with masses up to about 1.2 eV using {sup 3}He as a buffer gas.

• OSTI ID: 22156893
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2009, Issue 02; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
AXIONS
COUPLING
EV RANGE
GEV RANGE
HELIUM 3
HELIUM 4
MAGNETS
MASS
PHOTONS
PSEUDOSCALAR MESONS
SUN
TELESCOPES
X RADIATION