-
S. Aune,
K. Barth,
A. Belov,
S. Borghi,
H. Brauninger,
G. Cantatore,
J.M. Carmona,
S.A. Cetin,
J.I. Collar,
T. Dafni, [......],
A. Tomas,
M. Tsagri,
K. van Bibber,
T. Vafeiadis,
J. Villar,
J.K. Vogel,
L. Walckiers,
Y.Y.Y. Wong,
S.C. Yildiz,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: The CERN Axion Solar Telescope (CAST) is searching for solar axions which could be produced in the core of the Sun via the so-called Primakoff effect. Not only would these hypothetical particles solve the strong CP problem, but they are also one of the favored candidates for dark matter. In order to look for axions originating from the Sun, CAST uses a decommissioned LHC prototype magnet. In its 10 m long magnetic field region of 9 Tesla, axions could be reconverted into X-ray photons. Different X-ray detectors are installed on both ends of the magnet, which is mounted on a structure built to follow the Sun during sunrise and sunset for a total of about 3 hours per day. The analysis of the data acquired during the first phase of the experiment with vacuum in the magnetic field region yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV. In order to extend the sensitivity of the experiment to a wider mass range, the CAST experiment continues its search for axions with helium in the magnet bores. In this way it is possible to restore coherence of conversion for larger masses. Changing the pressure of the helium gas enables the experiment to scan different axion masses in the range of up to about 1.2 eV. Especially at high pressures, a precise knowledge of the gas density distribution is crucial to obtain accurate results. In the first part of this second phase of CAST, <sup>4</sup>He was used and the axion mass region was extended up to 0.39 eV, a part of phase space favored by axion models. In CAST's ongoing <sup>3</sup>He phase the studied mass range is now being extended further. In this contribution the final results of CAST's <sup>4</sup>He phase will be presented and the current status of the <sup>3</sup>He run will be given. This includes latest results as well as prospects of future axion experiments.
Nuclear Science Symposium Conference Record (NSS/MIC), 2010 IEEE; 12/2010
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CAST collaboration,
S. Andriamonje,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
H. Bräuninger,
J.M. Carmona,
S. Cebrián, [......],
J. Ruz,
I. Savvidis,
Y. Semertzidis, P. Serpico,
L. Stewart,
J. D. Vieira,
J. Villar,
J. Vogel,
L. Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a search for a high-energy axion emission signal from 7Li (0.478 MeV) and D(p, γ)3He (5.5 MeV) nuclear transitions using a low-background γ-ray calorimeter during Phase I of the CAST experiment. These so-called ``hadronic axions'' could provide a solution to the long-standing strong-CP problem and can be emitted from the solar core from nuclear M1 transitions. This is the first such search for high-energy pseudoscalar bosons with couplings to nucleons conducted using a helioscope approach. No excess signal above background was found.
Journal of Cosmology and Astroparticle Physics 03/2010; 2010(03):032. · 5.72 Impact Factor
-
CAST Collaboration: E. Arik,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
S. Borghi,
F. S. Boydag,
H. Bräuninger,
G. Cantatore, [......], P. Serpico,
S. K. Solanki,
R. Soufli,
L. Stewart,
M. Tsagri,
K van Bibber,
J5D. Villar,
J Vogel,
L Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipe of an LHC dipole. The analysis of the data recorded during the first phase of the experiment with vacuum in the magnet pipes has resulted in the most restrictive experimental limit on the coupling constant of axions to photons. In the second phase, CAST is operating with a buffer gas inside the magnet pipes in order to extent the sensitivity of the experiment to higher axion masses. We will present the first results on the $^{4}{\rm He}$ data taking as well as the system upgrades that have been operated in the last year in order to adapt the experiment for the $^{3}{\rm He}$ data taking. Expected sensitivities on the coupling constant of axions to photons will be given for the recent $^{3}{\rm He}$ run just started in March 2008.
11/2008;
-
Giovanni Cantatore,
for the CAST Collaboration: E. Arik,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
S. Borghi,
F. S. Boydag,
H. Bräuninger, [......], P. Serpico,
S. K. Solanki,
R. Soufli,
L. Stewart,
M. Tsagri,
K van Bibber,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.
10/2008;
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K Zioutas,
S Andriamonje,
V Arsov,
S Aune,
D Autiero,
F T Avignone,
K Barth,
A Belov,
B Beltrán,
H Bräuninger, [......],
M L Sarsa,
I Savvidis,
W Serber, P Serpico,
Y Semertzidis,
L Stewart,
J D Vieira,
J Villar,
L Walckiers,
K Zachariadou
[show abstract]
[hide abstract]
ABSTRACT: Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.
Physical Review Letters 04/2005; 94(12):121301. · 7.37 Impact Factor
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S. Andriamonje,
V. Arsov,
S. Aune,
D. Autiero,
F. Avignone,
K. Barth,
A. Belov,
B. Beltran,
H. Brauninger,
J. M. Carmona, [......],
I. Savvidis,
W. Serber, P. Serpico,
Y. Semertzidis,
L. Stewart,
J. D. Vieira,
J. Villar,
L Walckiers,
K Zachariadou,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.
Physical Review Letters, 121301 (2005).
-
The CAST Collaboration,
E Arik,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
S. Borghi,
G. Bourlis,
F. S. Boydag, [......],
I. Savvidis,
Y. Semertzidis, P. Serpico,
R. Soufli,
L. Stewart,
K van Bibber,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: 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 \hefour gas (Phase II) of variable pressure. The introduction of gas generated a refractive photon mass $m_\gamma$, thereby achieving the maximum possible conversion rate for those axion masses \ma that match $m_\gamma$. With 160 different pressure settings we have scanned \ma 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 $\gag\lesssim 2.17\times 10^{-10} {\rm GeV}^{-1}$ at 95% CL for $\ma \lesssim 0.4$ 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 $f_{\rm a}\sim10^{7}$ GeV. Currently in the second part of CAST Phase II, we are searching for axions with masses up to about 1.2 eV using \hethree as a buffer gas.
Journal of Cosmology and Astroparticle Physics, 008 (2009).
-
S. Andriamonje,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
H. Bräuninger,
J. M. Carmona,
S. Cebrián,
J. I. Collar, [......],
A Rodríguez,
J. Ruz,
I. Savvidis,
Y. Semertzidis, P. Serpico,
L. Stewart,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: We have searched for 14.4 keV solar axions or more general axion-like particles (ALPs), that may be emitted in the M1 nuclear transition of 57Fe, by using the axion-to-photon conversion in the CERN Axion Solar Telescope (CAST) with evacuated magnet bores (Phase I). From the absence of excess of the monoenergetic X-rays when the magnet was pointing to the Sun, we set model-independent constraints on the coupling constants of pseudoscalar particles that couple to two photons and to a nucleon g_{a\gamma} |-1.19 g_{aN}^{0}+g_{aN}^{3}|<1.36\times 10^{-16} GeV^{-1} for m_{a}<0.03 eV at the 95% confidence level.
Journal of Cosmology and Astroparticle Physics, 002 (2009).
-
S. Andriamonje,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltran,
H. Brauninger,
J. M. Carmona,
S. Cebrian,
J. I. Collar, [......],
J. Ruz,
I. Savvidis,
Y. Semertzidis, P. Serpico,
L. Stewart,
J. D. Vieira,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: We present the results of a search for a high-energy axion emission signal from 7Li (0.478 MeV) and D(p,gamma)3He (5.5 MeV) nuclear transitions using a low-background gamma-ray calorimeter during Phase I of the CAST experiment. These so-called "hadronic axions" could provide a solution to the long-standing strong-CP problem and can be emitted from the solar core from nuclear M1 transitions. This is the first such search for high-energy pseudoscalar bosons with couplings to nucleons conducted using a helioscope approach. No excess signal above background was found.
Journal of Cosmology and Astroparticle Physics, 032 (2010).
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S. Andriamonje,
S. Aune,
K. Barth,
A. Belov,
B. Beltrán,
H. Bräuninger,
J. M. Carmona,
S. Cebrián,
J. I. Collar,
T. Dafni, [......],
G. Raffelt,
J. Ruz,
H Riege, P. Serpico,
L. Stewart,
J. D. Vieira,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
C. Munoz, G. Yepes: The Dark Side of the Universe, American Institute of Physics, 395-401 (2006).
-
K. Zioutas,
S. Andriamonje,
V. Arsov,
S. Aune,
D. Autiero,
F T Avignone,
K. Barth,
A. Belov,
B. Beltrán,
H. Bräuninger, [......],
M. L. Sarsa,
I. Savvidis,
W. Serber, P. Serpico,
Y. Semertzidis,
L. Stewart,
J. D. Vieira,
J. Villar,
L Walckiers,
K Zachariadou
Physical Review Letters, v.94, 121301-1-121301-5 (2005).
-
S. Andriamonje,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltran,
H. Bräuninger,
J. M. Carmona,
S. Cebrian,
J. I. Collar, [......],
J. Ruz,
I. Savvidis,
Y. Semertzidis, P. Serpico,
L. Stewart,
J. Vieira,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
Journal of Cosmology and Astroparticle Physics (2007).
-
T. Dafni,
S. Andriamonje,
V. Arsov,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
H. Bräuninger,
J. Carmona, [......],
M. Sarsa,
I. Savvidis,
Y. Semertzidis,
W. Serber, P. Serpico,
L. Stewart,
J. Vieira,
J. Villar,
L Walckiers,
K. Zioutas
Journal of Physics: Conference Series, v.39, 117-119 (2006).
-
S. Andriamonje,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltran,
H. Brauninger,
J. M. Carmona,
S. Cebrian,
J. I. Collar, [......],
J. Ruz,
I. Savvidis,
Y. Semertzidis, P. Serpico,
L. Stewart,
J. Vieira,
J. Villar,
J Vogel,
L Walckiers,
K. Zioutas
[show abstract]
[hide abstract]
ABSTRACT: 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.
Journal of Cosmology and Astroparticle Physics, 010 (2007).
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E Arik,
S Aune,
D Autiero,
K Barth,
A Belov,
B Beltran,
G Bourlis,
F S Boydag,
H Brauninger,
J Carmona, [......],
Y Semertzidis, P Serpico,
R Soufli,
L Stewart,
S Tzamarias,
K Van Bibber,
J Villar,
J Vogel,
L Walckiers,
K Zioutas
-
B. Lakic,
E. Arik,
S. Aune,
D. Autiero,
K. Barth,
A. Belov,
B. Beltrán,
S. Borghi,
G. Bourlis,
F. S. Boydag, [......],
I. Savvidis,
Y. Semertzidis, P. Serpico,
R. Soufli,
L. Stewart,
K. van Bibber,
J. Villar,
J. Vogel,
L. Walckiers,
K. Zioutas
-1:65.
-
B. Lakic,
S. Andriamonje,
V. Arsov,
S. Aune,
D. Autiero,
F. Avignone,
K. Barth,
A. Belov,
B. Beltran,
H. Brauninger, [......],
M. L. Sarsa,
I. Savvidis, P. Serpico,
Y. Semertzidis,
L. Stewart,
J. D. Vieira,
J. Villar,
L. Walckiers,
K. Zachariadou,
K. Zioutas
-1:22.
