L. Stewart

An improved limit on the axion–photon coupling from the CAST experiment

We have searched for solar axions or similar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup with improved conditions in all detectors. From the absence of excess X-rays when the magnet was pointing to the Sun, we set an upper limit on the axion-photon coupling of 8.8 x 10^{-11} GeV^{-1} at 95% CL for m_a<~ 0.02 eV. This result is the best experimental limit over a broad range of axion masses and for m_a<~ 0.02 eV also supersedes the previous limit derived from energy-loss arguments on globular-cluster stars.

Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with 3He Buffer Gas

S. Aune, K. Barth, A. Belov, S. Borghi, ∗ H. Bräuninger, G. Cantatore, J. M. Carmona, S. A. Cetin, J. I. Collar, T. Dafni, M. Davenport, C. Eleftheriadis, N. Elias, C. Ezer, G. Fanourakis, E. Ferrer-Ribas, P. Friedrich, J. Galán, J. A. Garćıa, A. Gardikiotis, E. N. Gazis, T. Geralis, I. Giomataris, S. Gninenko, H. Gómez, E. Gruber, T. Guthörl, R. Hartmann, † F. Haug, M. D. Hasinoff, D. H. H. Hoffmann, F. J. Iguaz, ‡ I. G. Irastorza, J. Jacoby, K. Jakovčić, M. Karuza, K. Königsmann, R. Kotthaus, M. Krčmar, M. Kuster, 16, § B. Lakić, ¶ J. M. Laurent, A. Liolios, A. Ljubičić, V. Lozza, G. Lutz, † G. Luzón, J. Morales, ∗∗ T. Niinikoski, †† A. Nordt, 16, ‡‡ T. Papaevangelou, M. J. Pivovaroff, G. Raffelt, T. Rashba, H. Riege, A. Rodŕıguez, M. Rosu, J. Ruz, 2 I. Savvidis, P. S. Silva, S. K. Solanki, L. Stewart, A. Tomás, M. Tsagri, ‡‡ K. van Bibber, §§ T. Vafeiadis, 9, 12 J. Villar, J. K. Vogel, 20, ¶¶ S. C. Yildiz, and K. Zioutas 12

New CAST limit on the axion–photon interaction

During 2003--2015, the CERN Axion Solar Telescope (CAST) has searched for

Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

a\to\gamma

New solar axion search using the CERN Axion Solar Telescope with He 4 filling

conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. In its final phase of solar axion searches (2013--2015), CAST has returned to evacuated magnet pipes, which is optimal for small axion masses. The absence of a significant signal above background provides a world leading limit of

Search for 14.4 keV solar axions emitted in the M1-transition of 57Fe nuclei with CAST

g_{a\gamma} < 0.66 \times 10^{-10} {\rm GeV}^{-1}

Status and perspectives of the CAST experiment

(95% C.L.) on the axion-photon coupling strength for

Search for Solar Axions with the CAST-Experiment

m_a \lesssim 0.02

Search for solar axions: the CAST experiment

eV. Compared with the first vacuum phase (2003--2004), the sensitivity was vastly increased with low-background x-ray detectors and a new x-ray telescope. These innovations also serve as pathfinders for a possible next-generation axion helioscope.

First results from the CAST experiment

Introduction.—The most promising method to searchfor axions and axion-likeparticles (ALPs) [1–4], low-massbosons with a two-photon interaction vertex, is their con-version to photons in macroscopic magnetic fields [5–7].This approach includes the search for solar axions by thehelioscope technique [8–15], photon regeneration exper-iments (“shining light through a wall”) [16–18], axion-photon conversion in astrophysical B fields [19–22], andthe search for galactic axion dark matter [23–27].One limiting factor in any of these efforts is the mo-mentum difference between freely propagating photonsand axions caused by the axion mass m