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337 results on '"Zioutas K"'

302. Search for narrow signals in the γ-spectrum from pp̄ annihilation at rest

Author

Adiels, L., primary, Backenstoss, G., additional, Bergström, I., additional, Carius, S., additional, Charalambous, S., additional, Cooper, M.D., additional, Findeisen, Ch., additional, Hatzifotiadou, D., additional, Kerek, A., additional, Pavlopoulos, P., additional, Repond, J., additional, Tauscher, L., additional, Tröster, D., additional, Williams, M.C.S., additional, and Zioutas, K., additional

Published
1986
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306. Signals for invisible matter from solar - terrestrial observations

Author

Bertolucci Sergio, Zioutas Konstantin, Hofmann Sebastian, and Maroudas Marios

Subjects
Physics, QC1-999
Abstract

Gravitational lensing of invisible streaming matter towards the Sun or the Earth could be the explanation of puzzling solar/terrestrial phenomena. We have analyzed solar flares, EUV emission and also the global ionization content of the Earth atmosphere. Assuming that this invisible matter has some form of interaction with normal matter and that there exist preferred directions in its flow, then one would expect an enhanced activity at certain planetary longitudes, which is also observed. The broad velocity spectrum of the assumed constituents makes it difficult at this stage to identify the origin of the stream(s) or the nature of its constituents.

Published
2017
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307. Planetary Relationships to Birth (Imputed Conception) Rates in Humans: A Signature of Cosmic Origin?

Author

Georgiopoulou, E., Hofmann, S., Maroudas, M., Mastronikolis, A., Matteson, E. L., Tsagri, M., and Zioutas, K.

Subjects
*SOLAR cycle, *DARK matter, *BIRTH rate, *JUPITER (Planet), *STATISTICAL significance
Abstract

This report addresses the time dependence of normal biomedical processes. The conception rate in humans shows relationships that strikingly coincide with planetary periodicities like the orbital period of Jupiter, the 11 years solar cycle and the 237 days Jupiter–Venus synod, and the combined dependence on Jupiter with Mars' orbital position. The birth rates are used as conception surrogates based on a data set available from the Minnesota Department of Health. The statistical significance of each independent analysis (far) exceeds 5 σ. This result cannot be explained with known science. As with other observations in Physics and Medicine (i.e., melanoma), tentatively the only viable explanation we have is the otherwise invisible streaming matter from the dark Universe we live in. The favored dark matter scenario involves streams or clusters as opposed to an isotropic dark sector. The dark Universe scenario has been the driving idea for this type of work. The high sensitivity of living matter to the tiniest external impact might help identify the nature of the dark matter particles, a major problem in all physics since the 1930s. This work is a model for evaluating other biological processes and mutation rates. [ABSTRACT FROM AUTHOR]

Published
2023
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320. First Results on the Search for Chameleons with the KWISP Detector at CAST

Author

C. Krieger, Sami K. Solanki, K. Barth, B. Döbrich, S. Neff, Michael J. Pivovaroff, J. Castel, A. Belov, I. Tsagris, E. Ruiz Chóliz, Marc Schumann, A. Ozbey, A. V. Dermenev, A. Bayirli, L. Stewart, S. C. Yildiz, J. Ruz, J. G. Garza, L. Miceli, Serkant Ali Cetin, S. Arguedas Cuendis, T. Dafni, Giovanni Cantatore, J. M. Laurent, F.J. Iguaz, T. Vafeiadis, J. M. Carmona, Klaus Kurt Desch, I. G. Irastorza, M. Maroudas, M. D. Hasinoff, S. N. Gninenko, Biljana Lakić, I. Ortega, H. Bräuninger, M. Vretenar, Konstantin Zioutas, Søren Schmidt, Marin Karuza, Sebastian Baum, Julia Vogel, G. Luzón, A. Gardikiotis, Yannis K. Semertzidis, J. Baier, M. Davenport, Krešimir Jakovčić, M. Rosu, H. Fischer, Wolfgang Funk, J. A. García, Dieter Hoffmann, J. Kaminski, Arguedas Cuendis, S., Baier, J., Barth, K., Baum, S., Bayirli, A., Belov, A., Brauninger, H., Cantatore, G., Carmona, J. M., Castel, J. F., Cetin, S. A., Dafni, T., Davenport, M., Dermenev, A., Desch, K., Dobrich, B., Fischer, H., Funk, W., Garcia, J. A., Gardikiotis, A., Garza, J. G., Gninenko, S., Hasinoff, M. D., Hoffmann, D. H. H., Iguaz, F. J., Irastorza, I. G., Jakovcic, K., Kaminski, J., Karuza, M., Krieger, C., Lakic, B., Laurent, J. M., Luzon, G., Maroudas, M., Miceli, L., Neff, S., Ortega, I., Ozbey, A., Pivovaroff, M. J., Rosu, M., Ruz, J., Choliz, E. R., Schmidt, S., Schumann, M., Semertzidis, Y. K., Solanki, S. K., Stewart, L., Tsagris, I., Vafeiadis, T., Vogel, J. K., Vretenar, M., Yildiz, S. C., Zioutas, K., and İÜC

Subjects
Astrophysics and Astronomy, Physics - Instrumentation and Detectors, Photon, Cosmology and Nongalactic Astrophysics (astro-ph.CO), astro-ph.SR, Physics::Instrumentation and Detectors, Chameleons, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 7. Clean energy, High Energy Physics - Experiment, law.invention, Telescope, High Energy Physics - Experiment (hep-ex), Optics, law, Opto-mechanical sensor, 0103 physical sciences, Chameleon, Dark energy, Detectors and Experimental Techniques, 010306 general physics, chameleons, dark energy, opto-mechanical sensor, interferometry, Axion, physics.ins-det, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Coupling, 010308 nuclear & particles physics, business.industry, hep-ex, Detector, Michelson interferometer, Astronomy and Astrophysics, Instrumentation and Detectors (physics.ins-det), Interferometry, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, astro-ph.CO, Direct coupling, business, Particle Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report on a first measurement with a sensitive opto-mechanical force sensor designed for the direct detection of coupling of real chameleons to matter. These dark energy candidates could be produced in the Sun and stream unimpeded to Earth. The KWISP detector installed on the CAST axion search experiment at CERN looks for tiny displacements of a thin membrane caused by the mechanical effect of solar chameleons. The displacements are detected by a Michelson interferometer with a homodyne readout scheme. The sensor benefits from the focusing action of the ABRIXAS X-ray telescope installed at CAST, which increases the chameleon flux on the membrane. A mechanical chopper placed between the telescope output and the detector modulates the incoming chameleon stream. We present the results of the solar chameleon measurements taken at CAST in July 2017, setting an upper bound on the force acting on the membrane of $80$~pN at 95\% confidence level. The detector is sensitive for direct coupling to matter $10^4 \leq\beta_m \leq 10^8$, where the coupling to photons is locally bound to $\beta_\gamma \leq 10^{11}$., Comment: 21 pages, 12 figures

Published
2019

322. Towards a medium-scale axion helioscope and haloscope

Author

R. Djilkibaev, F. T. Avignone, V. K. Eremin, Sergey Troitsky, Serkant Ali Cetin, A. Gardikiotis, D. Semenov, Grigory Rubtsov, M. N. Pavlinsky, V. N. Muratova, Maxim Libanov, Vassilis Anastassopoulos, Pierre Sikivie, S. Molkov, Leonid Kravchuk, V. A. Matveev, Marin Karuza, Dieter H. H. Hoffmann, N. Golubev, Giovanni Cantatore, Konstantin Zioutas, Peter Tinyakov, E. V. Unzhakov, S. N. Gninenko, Andrei M. Bykov, M. Maroudas, A. V. Derbin, H. Fischer, K. V. Ptitsyna, V. S. Pantuev, A. A. Lutovinov, I. Drachnev, A. Gangapshev, Igor Tkachev, A. Spiridonov, Anastassopoulos, V., Avignone, F., Bykov, A., Cantatore, G., Cetin, S. A., Derbin, A., Drachnev, I., Djilkibaev, R., Eremin, V., Fischer, H., Gangapshev, A., Gardikiotis, A., Gninenko, S., Golubev, N., Hoffmann, D. H. H., Karuza, M., Kravchuk, L., Libanov, M., Lutovinov, A., Maroudas, M., Matveev, V., Molkov, S., Muratova, V., Pantuev, V., Pavlinsky, M., Ptitsyna, K., Rubtsov, G., Semenov, D., Sikivie, P., Spiridonov, A., Tinyakov, P., Tkachev, I., Troitsky, S., Unzhakov, E., and Zioutas, K.

Subjects
Particle physics, solar axion, Physics::Instrumentation and Detectors, Axions, FOS: Physical sciences, 01 natural sciences, magnetic helioscope, High Energy Physics - Phenomenology, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics::Theory, High Energy Physics - Phenomenology (hep-ph), Axion, 0103 physical sciences, 010306 general physics, Instrumentation, Mathematical Physics, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Helioscope, 010308 nuclear & particles physics, solar axions, High Energy Physics::Phenomenology, Astrophysics::Instrumentation and Methods for Astrophysics, Medium scale, Solar telescope, Dark matter halo, Halo, CERN Axion Solar Telescope
Abstract

We discuss the physics case for and the concept of a medium-scale axion helioscope with sensitivities in the axion-photon coupling a few times better than CERN Axion Solar Telescope (CAST). Search for an axion-like particle with these couplings is motivated by several persistent astrophysical anomalies. We present early conceptual design, existing infrastructure, projected sensitivity and timeline of such a helioscope (Troitsk Axion Solar Telescope Experiment, TASTE) to be constructed in the Institute for Nuclear Research, Troitsk, Russia. The proposed instrument may be also used for the search of dark-matter halo axions., 38 pages, 15 figures, JINST style. V2: misprints corrected. V3: minor clarifications and detalizations, version accepted by JINST

Published
2017

323. KWISP: An ultra-sensitive force sensor for the Dark Energy sector

Author

A. Gardikiotis, Yannis K. Semertzidis, Konstantin Zioutas, Marin Karuza, Dieter H. H. Hoffmann, Giovanni Cantatore, Karuza, M., Cantatore, Giovanni, Gardikiotis, A., Hoffmann, D. H. H., Semertzidis, Y. K., and Zioutas, K.

Subjects
opto-mechanical sensor, chameleons, dark energy, Fabry–Perot interferometer, Physics - Instrumentation and Detectors, Chameleons, Dark Energy, Fabry-Perot interferometer, Opto-mechanical sensor, Astronomy and Astrophysics, Space and Planetary Science, FOS: Physical sciences, Physics::Optics, General Relativity and Quantum Cosmology (gr-qc), Kinetic energy, 01 natural sciences, Displacement (vector), General Relativity and Quantum Cosmology, law.invention, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Optics, law, 0103 physical sciences, Chameleon, Detectors and Experimental Techniques, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Physics, 010308 nuclear & particles physics, business.industry, Gravitational wave, Resonance, Instrumentation and Detectors (physics.ins-det), Astronomy and Astrophysic, Interferometry, Optical cavity, Direct coupling, business, Astrophysics - Instrumentation and Methods for Astrophysics, Fabry–Pérot interferometer
Abstract

An ultra-sensitive opto-mechanical force sensor has been built and tested in the optics laboratory at INFN Trieste. Its application to experiments in the Dark Energy sector, such as those for Chameleon-type WISPs, is particularly attractive, as it enables a search for their direct coupling to matter. We present here the main characteristics and the absolute force calibration of the KWISP (Kinetic WISP detection) sensor. It is based on a thin Si3N4 micro-membrane placed inside a Fabry-Perot optical cavity. By monitoring the cavity characteristic frequencies it is possible to detect the tiny membrane displacements caused by an applied force. Far from the mechanical resonant frequency of the membrane, the measured force sensitivity is 5.0e-14 N/sqrt(Hz), corresponding to a displacement sensitivity of 2.5e-15 m/sqrt(Hz), while near resonance the sensitivity is 1.5e-14 N/sqrt(Hz), reaching the estimated thermal limit, or, in terms of displacement, 7.5e-16 N/sqrt(Hz). These displacement sensitivities are comparable to those that can be achieved by large interferometric gravitational wave detectors., 9 pages, 8 figures in color

Published
2016

324. Search for chameleons with CAST

Author

J. I. Collar, M. Arik, F.J. Iguaz, Milica Krčmar, Javier Galan, Philippe Brax, José Villar, S. C. Yildiz, Marin Karuza, Julia Vogel, K. Barth, G. Luzón, Biljana Lakić, M. Davenport, M. Kavuk, I. Ortega, Joachim Jacoby, Heinrich Bräuninger, Serkant Ali Cetin, T. Geralis, Georg G. Raffelt, E. Ferrer-Ribas, M. Rosu, H. Riege, T. Papaevangelou, J. G. Garza, Theodoros Vafeiadis, A. Belov, I. G. Irastorza, S. Aune, A. Gardikiotis, Krešimir Jakovčić, F. Haug, I. Savvidis, J. M. Laurent, Dieter H. H. Hoffmann, Peter Friedrich, S. Neff, Charles J. Hailey, M. J. Pivovaroff, Konstantin Zioutas, T. Dafni, Vassilis Anastassopoulos, J. Ruz, I. Giomataris, Klaus Kurt Desch, I. Lavrentyev, Finn Erland Christensen, C. Eleftheriadis, Ante Ljubičić, A. V. Dermenev, A. Upadhye, C. Krieger, Sami K. Solanki, J. M. Carmona, M. D. Hasinoff, Georgios Fanourakis, G. Cantatore, Evangelos Gazis, Jochen Kaminski, Anders Clemen Jakobsen, A. Krüger, A. Liolios, J. A. Garcia, Doğuş Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, TR3959, Çetin, Serkant Ali, Anastassopoulos, V, Arik, M., Aune, S., Barth, K., Belov, A., Bräuninger, H., Cantatore, Giovanni, Carmona, J. M., Cetin, S. A., Christensen, F., Collar, J. I., Dafni, T., Davenport, M., Desch, K., Dermenev, A., Eleftheriadis, C., Fanourakis, G., Ferrer Ribas, E., Friedrich, P., Galán, J., García, J. A., Gardikiotis, A., Garza, J. G., Gazis, E. N., Geralis, T., Giomataris, I., Hailey, C., Haug, F., Hasinoff, M. D., Hoffmann, D. H. H., Iguaz, F. J., Irastorza, I. G., Jacoby, J., Jakobsen, A., Jakovčić, K., Kaminski, J., Karuza, M., Kavuk, M., Krčmar, M., Krieger, C., Krüger, A., Lakić, B., Laurent, J. M., Liolios, A., Ljubičić, A., Luzón, G., Neff, S., Ortega, I., Papaevangelou, T., Pivovaroff, M. J., Raffelt, G., Riege, H., Rosu, M., Ruz, J., Savvidis, I., Solanki, S. K., Vafeiadis, T., Villar, J. A., Vogel, J. K., Yildiz, S. C., Zioutas, K., Brax, P., Lavrentyev, I., and Upadhye, A.

Subjects
Nuclear and High Energy Physics, Astrophysics and Astronomy, Photon, Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, FOS: Physical sciences, Tachocline, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, SDD, X-ray, High Energy Physics - Phenomenology (hep-ph), 0103 physical sciences, Chameleon, Dark energy, 010306 general physics, Axion, Solar and Stellar Astrophysics (astro-ph.SR), Primakoff effect, Coupling constant, Coupling, Physics, CAST, 010308 nuclear & particles physics, Instrumentation and Detectors (physics.ins-det), lcsh:QC1-999, High Energy Physics - Phenomenology, Astrophysics - Solar and Stellar Astrophysics, CERN Axion Solar Telescope, lcsh:Physics
Abstract

In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter ($\beta_{\rm m}$) and to photons ($\beta_{\gamma}$) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1$\,$keV to 400$\,$eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600$\,$eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of $\beta_{\gamma}\!\lesssim\!10^{11}$ for $1, Comment: 8 pages, 12 figures

Published
2015
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325. The IAXO Helioscope

Author

I. Savvidis, I. G. Irastorza, I. Ortega, Toyokazu Sekiguchi, K Saikawa, M. Davenport, Serkant Ali Cetin, C. Eleftheriadis, C. Krieger, D. Chelouche, O. Limousin, Charles J. Hailey, P. Vedrine, G. Fanourakis, S. Caspi, Gianpaolo Carosi, Javier Redondo, A. Tomás, Ioannis Giomataris, Javier Galan, Hector Gomez, Pierre Sikivie, A.C. Jakobsen, S. Russenschuck, J. G. Garza, F.J. Iguaz, Kenichi Imai, K. van Bibber, Pierre Brun, Marin Karuza, A. Dael, Takashi Hiramatsu, S. Gninenko, A. Lindner, M. Betz, Dieter H. H. Hoffmann, A. Liolios, Jochen Kaminski, E. Ferrer Ribas, Theodoros Geralis, V. N. Muratova, Julia Vogel, Yannis K. Semertzidis, Theodoros Vafeiadis, Babette Döbrich, Sergey Troitsky, G. Luzón, A. V. Derbin, D. González-Díaz, Michael J. Pivovaroff, F. T. Avignone, J. A. Garcia, Joerg Jaeckel, Amanda Weltman, W. C. Wester, Georg G. Raffelt, Masahiro Kawasaki, A. Dudarev, Andreas Ringwald, Krešimir Jakovčić, T. Dafni, Milica Krčmar, J.A. Villar, A. Diago, Eduardo Guendelman, Konstantin Zioutas, Dieter Horns, Klaus Kurt Desch, J. Ruz, J. M. Carmona, Giovanni Cantatore, Benito Gimeno, F.E. Christensen, P. Brax, T. Papaevangelou, L. Walckiers, Jordi Isern, Konstantinos Kousouris, I. Dratchnev, I. Shilon, Fritz Caspers, C. Nones, S. Matsuki, S. C. Yildiz, Biljana Lakić, H. H. J. ten Kate, E. Armengaud, H. Silva, Ribas, E. Ferrer, Armengaud, E., Avignone, F. T., Betz, M., Brax, P., Brun, P., Cantatore, Giovanni, Carmona, J. M., Carosi, G. P., Caspers, F., Caspi, S., Cetin, S. A., Chelouche, D., Christensen, F. E., Dael, A., Dafni, T., Davenport, M., Derbin, A. V., Desch, K., Diago, A., Döbrich, B., Dratchnev, I., Dudarev, A., Eleftheriadis, C., Fanourakis, G., Galán, J., García, J. A., Garza, J. G., Geralis, T., Gimeno, B., Giomataris, I., Gninenko, S., Gómez, H., González Diaz, D., Guendelman, E., Hailey, C. J., Hiramatsu, T., Hoffmann, D. H. H., Horns, D., Iguaz, F. J., Irastorza, I. G., Isern, J., Imai, K., Jaeckel, J., Jakobsen, A. C., Jakovčić, K., Kaminski, J., Kawasaki, M., Karuza, M., Krčmar, M., Kousouris, K., Krieger, C., Lakić, B., Limousin, O., Lindner, A., Liolios, A., Luzón, G., Matsuki, S., Muratova, V. N., Nones, C., Ortega, I., Papaevangelou, T., Pivovaroff, M. J., Raffelt, G., Redondo, J., Ringwald, A., Russenschuck, S., Ruz, J., Saikawa, K., Savvidis, I., Sekiguchi, T., Semertzidis, Y. K., Shilon, I., Sikivie, P., Silva, H., Ten Kate, H. H. J., Tomas, A., Troitsky, S., Vafeiadis, T., Van Bibber, K., Vedrine, P., Villar, J. A., Vogel, J. K., Walckiers, L., Weltman, A., Wester, W., Yildiz, S. C., Zioutas, K., Doğuş Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, TR3959, and Çetin, Serkant Ali

Subjects
History, Particle physics, QCD axion, Dark matter, X-ray optics, Detectable Signal, 7. Clean energy, magnetic helioscope, dark matter, Education, Solar tracker, Optics, QCD axions, ddc:530, Detectors and Experimental Techniques, Axion, Physics, Helioscope, Fourth Generation, business.industry, Technical Design, Detector, MicroMegas detector, Toroidal Magnets, Low Background Detectors, Computer Science Applications, Magnet, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Feasibility Studies, X-ray Focusing Optics, business
Abstract

Çetin, Serkant Ali (Dogus Author) -- Conference full title: 7th International Symposium on Large TPCs for Low-Energy Rare Event Detection; Institute of Astroparticle Physics (APC) Campus - Paris Diderot UniversityParis; France; 15 December 2014 through 17 December 2014 The IAXO (International Axion Experiment) is a fourth generation helioscope with a sensitivity, in terms of detectable signal counts, at least 104 better than CAST phase-I, resulting in sensitivity on gaγ one order of magnitude better. To achieve this performance IAXO will count on a 8-coil toroidal magnet with 60 cm diameter bores and equipped with X-ray focusing optics into 0.20 cm2 spots coupled to ultra-low background Micromegas X-ray detectors. The magnet will be on a platform that will allow solar tracking for 12 hours per day. The next short term objectives are to prepare a Technical Design Report and to construct the first prototypes of the hardware main ingredients: demonstration coil, X-ray optics and low background detector while refining the physics case and studying the feasibility studies for Dark Matter axions.

Published
2015
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326. Conceptual design of the International Axion Observatory (IAXO)

Author

A. Liolios, P. Vedrine, G. Fanourakis, Doron Chelouche, Klaus Kurt Desch, Serkant Ali Cetin, I. G. Irastorza, Konstantin Zioutas, Gianpaolo Carosi, Javier Redondo, I. Dratchnev, Ken'ichi Saikawa, Ioannis Giomataris, B. Gimeno, Pierre Brun, Eduardo Guendelman, A. Dael, B. Döbrich, S. Gninenko, E. Ferrer-Ribas, C. Krieger, L. Walckiers, J. Ruz, J. A. García, S. Matsuki, Milica Krčmar, I. Shilon, S. Russenschuck, Kenichi Imai, J.A. Villar, I. Ortega, A. Diago, J. Galán, Sergey Troitsky, V. N. Muratova, Joerg Jaeckel, I. Savvidis, Ph. Brax, Amanda Weltman, H. Silva, C. Nones, Charles J. Hailey, Haley Louise Gomez, Dieter Horns, K. van Bibber, Krešimir Jakovčić, S. C. Yildiz, Olivier Limousin, Jordi Isern, Finn Erland Christensen, T. Vafeiadis, William Wester, C. Eleftheriadis, Michael J. Pivovaroff, Theodoros Geralis, Biljana Lakić, Julia Vogel, A. Dudarev, Andreas Ringwald, Fritz Caspers, A. V. Derbin, K. Kousouris, G. Luzón, T. Papaevangelou, J. M. Carmona, J. Kaminski, Anders Clemen Jakobsen, H. H. J. ten Kate, T. Dafni, A. Lindner, M. Betz, Georg G. Raffelt, Marin Karuza, S. Caspi, Masahiro Kawasaki, Giovanni Cantatore, Eric Armengaud, J. G. Garza, F.J. Iguaz, F. T. Avignone, A. Tomás, T. Sekiguchi, M. Davenport, Pierre Sikivie, Takashi Hiramatsu, Dieter H. H. Hoffmann, Diego González-Díaz, Yannis K. Semertzidis, Doğuş Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, TR3959, Çetin, Serkant Ali, Armengaud, E., Avignone, F. T., Betz, M., Brax, P., Brun, P., Cantatore, Giovanni, Carmona, J. M., Carosi, G. P., Caspers, F., Caspi, S., Cetin, S. A., Chelouche, D., Christensen, F. E., Dael, A., Dafni, T., Davenport, M., Derbin, A. V., Desch, K., Diago, A., Döbrich, B., Dratchnev, I., Dudarev, A., Eleftheriadis, C., Fanourakis, G., Ferrer Ribas, E., Galán, J., García, J. A., Garza, J. G., Geralis, T., Gimeno, B., Giomataris, I., Gninenko, S., Gómez, H., Gonźlez Díaz, D., Guendelman, E., Hailey, C. J., Hiramatsu, T., Hoffmann, D. H. H., Horns, D., Iguaz, F. J., Irastorza, I. G, Isern, J., Imai, K., Jakobsen, A. C., Jaeckel, J., Jakovčić, K., Kaminski, J., Kawasaki, M., Karuza, M., Krčmar, M., Kousouris, K., Krieger, C., Lakić, B., Limousin, O., Lindner, A., Liolios, A., Luzón, G., Matsuki, S., Muratova, V. N., Nones, C., Ortega, I., Papaevangelou, T., Pivovaroff, M. J., Raffelt, G., Redondo, J., Ringwald, A., Russenschuck, S., Ruz, J., Saikawa, K., Savvidis, I., Sekiguchi, T., Semertzidis, Y. K., Shilon, I., Sikivie, P., Silva, H., Kate, H. Ten, Tomas, A., Troitsky, S., Vafeiadis, T., Bibber, K. Van, Vedrine, P., Villar, J. A., Vogel, J. K., Walckiers, L., Weltman, A., Wester, W., Yildiz, S. C., and Zioutas, K.

Subjects
MICROPIC, Physics - Instrumentation and Detectors, Photon, axions, Parameter space, 7. Clean energy, High Energy Physics - Experiment, Dark Matter detectors (WIMPs, axions, etc.), High Energy Physics - Experiment (hep-ex), Observatory, etc.), Micropattern gaseous detectors (MSGC, GEM, THGEM, RETHGEM, MHSP, MICROPIC, MICROMEGAS, InGrid, etc), Detectors and Experimental Techniques, Instrumentation, Mathematical Physics, Physics, GEM, solar [axion], Dark Matter Detectors (Wimps, Axions, etc.), MicroMegas detector, X-ray detectors, Instrumentation and Detectors (physics.ins-det), Large detector systems for particle and astroparticle physics, solar, observatory, MICROMEGAS, MHSP, axion-like particles, proposed experiment, dark matter detectors, x-ray detectors, Micropattern gaseous detectors, large detector systems for particle and astroparticle physics, Micromegas, X-ray detector, Particle physics, optics [X-ray], FOS: Physical sciences, Superconducting magnet, Micropattern gaseous detectors (MSGC, ddc:610, Axion, activity report, Dark Matter detectors (WIMPs, superconductivity [magnet], etc), Helioscope, sensitivity, InGrid, RETHGEM, Orders of magnitude (time), axion, Large detector systems for particle and astroparticle physic, THGEM, Micropattern Gaseous Detectors (MSGC, Gem, THGEM, Rethgem, MHSP, Micropic, Micromegas, In Grid
Abstract

The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be about 4-5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few $\times 10^{-12}$ GeV$^{-1}$ and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling $g_{ae}$ with sensitivity $-$for the first time$-$ to values of $g_{ae}$ not previously excluded by astrophysics. With several other possible physics cases, IAXO has the potential to serve as a multi-purpose facility for generic axion and ALP research in the next decade. In this paper we present the conceptual design of IAXO, which follows the layout of an enhanced axion helioscope, based on a purpose-built 20m-long 8-coils toroidal superconducting magnet. All the eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able to focus the signal photons into $\sim 0.2$ cm$^2$ spots that are imaged by ultra-low-background Micromegas x-ray detectors. The magnet is built into a structure with elevation and azimuth drives that will allow for solar tracking for $\sim$12 h each day., Comment: 47 pages, submitted to JINST

Published
2014
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327. Detecting solar chameleons through radiation pressure

Author

Marin Karuza, Sebastian Baum, Dieter H. H. Hoffmann, A. Upadhye, Konstantin Zioutas, Yannis K. Semertzidis, Giovanni Cantatore, Baum, S., Cantatore, Giovanni, Hoffmann, D. H. H., Karuza, Marin, Semertzidis, Y. K., Upadhye, A., and Zioutas, K.

Subjects
Astrophysics and Astronomy, Nuclear and High Energy Physics, Physics - Instrumentation and Detectors, Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Metric expansion of space, Theoretical physics, chameleons, dark energy, opto-mechanical sensors, Tests of general relativity, Fysik, dark energy, Instrumentation and Methods for Astrophysics (astro-ph.IM), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Scalar (physics), Instrumentation and Detectors (physics.ins-det), lcsh:QC1-999, chameleons, Radiation pressure, Physical Sciences, Dark energy, opto-mechanical sensors, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, lcsh:Physics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Light scalar fields can drive the accelerated expansion of the universe. Hence, they are obvious dark energy candidates. To make such models compatible with tests of General Relativity in the solar system and "fifth force" searches on Earth, one needs to screen them. One possibility is the so-called "chameleon" mechanism, which renders an effective mass depending on the local matter density. If chameleon particles exist, they can be produced in the sun and detected on Earth exploiting the equivalent of a radiation pressure. Since their effective mass scales with the local matter density, chameleons can be reflected by a dense medium if their effective mass becomes greater than their total energy. Thus, under appropriate conditions, a flux of solar chameleons may be sensed by detecting the total instantaneous momentum transferred to a suitable opto-mechanical force/pressure sensor. We calculate the solar chameleon spectrum and the reach in the chameleon parameter space of an experiment using the preliminary results from a force/pressure sensor, currently under development at INFN Trieste, to be mounted in the focal plane of one of the X-Ray telescopes of the CAST experiment at CERN. We show, that such an experiment signifies a pioneering effort probing uncharted chameleon parameter space., Comment: revised version

Published
2014
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328. Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with (3)He Buffer Gas

Author

M, Arik, 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, García, 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, B, Lakić, J M, Laurent, A, Liolios, A, Ljubičić, V, Lozza, G, Lutz, G, Luzón, J, Morales, T, Niinikoski, A, Nordt, T, Papaevangelou, M J, Pivovaroff, G, Raffelt, T, Rashba, H, Riege, A, Rodríguez, M, Rosu, J, Ruz, I, Savvidis, P S, Silva, S K, Solanki, L, Stewart, A, Tomás, M, Tsagri, K, van Bibber, T, Vafeiadis, J A, Villar, J K, Vogel, S C, Yildiz, K, Zioutas, Arik, M., Aune, S., Barth, K., Belov, A., Borghi, S., Brauninger, H., Cantatore, Giovanni, Carmona, J. M., Cetin, S. A., Collar, J. I., Dafni, T., Davenport, M., Eleftheriadis, C., Elias, N., Ezer, C., Fanourakis, G., Ferrer Ribas, E., Friedrich, P., Galan, J., Garcia, J. A., Gardikiotis, A., Gazis, E. N., Geralis, T., Giomataris, I., Gninenko, S., Gomez, H., Gruber, E., Guthorl, T., Hartmann, R., Haug, F., Hasinoff, M. D., Hoffmann, D. H. H., Iguaz, F. J., Irastorza, I. G., Jacoby, J., Jakovcic, K., Karuza, M., Konigsmann, K., Kotthaus, R., Krcmar, M., Kuster, M., Lakic, B., Laurent, J. M., Liolios, A., Ljubicic, A., Lozza, Valentina, Lutz, G., Luzon, G., Morales, J., Niinikoski, T., Nordt, A., Papaevangelou, T., Pivovaroff, M. J., Raffelt, G., Rashba, T., Riege, H., Rodriguez, A., Rosu, M., Ruz, J., Savvidis, I., Silva, P. S., Solanki, S. K., Stewart, L., Tomas, A., Tsagri, M., van Bibber, K., Vafeiadis, T., Villar, J. A., Vogel, J. K., Yildiz, S. C., and Zioutas, K.

Subjects
solar axion, low background detectors, solar axions, photons, dark matter
Abstract

The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. 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(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

Published
2011

329. Photon Production From The Scattering of Axions Out of a Solenoidal Magnetic Field

Author

Giovanni Cantatore, I. Shilon, Konstantin Zioutas, Eduardo Guendelman, Guendelman, E. I., Shilon, I., Cantatore, Giovanni, and Zioutas, K.

Subjects
Quantum chromodynamics, Physics, High Energy Physics - Theory, Particle physics, Photon, axions, Solenoidal vector field, Scattering, FOS: Physical sciences, Astronomy and Astrophysics, Primakoff effect, solar physics, Resonance (particle physics), Cross section (physics), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Theory (hep-th), axion, Axion
Abstract

We calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a 2D delta-function, a cylindrical step function and a 2D Gaussian distribution, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the axion-photon conversion probability which could be expected in a reasonable experimental situation. The calculated conversion probabilities for QCD inspired axions are bigger by a factor of 2.67 (for the cylindrical step function case) than those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect. We also consider scattering at a resonance $E_{axion} \sim m_{axion}$, which corresponds to the scattering from a delta-function and gives the most enhanced results. Finally, we analyze the results of this work in the astrophysical extension to suggest a way in which they may be directed to a solution to some basic solar physics problems and, in particular, the coronal heating problem., Comment: 19 pages, 1 figure, added analysis of our results in the astrophysical extension

Published
2009
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332. Improved search for solar chameleons with a GridPix detector at CAST

Author

Wolfgang Funk, Milica Krčmar, T. Geralis, M. Maroudas, S. C. Yildiz, I. G. Irastorza, Joachim Jacoby, Sofia Kostoglou, Babette Döbrich, Sergei Gninenko, Giovanni Cantatore, C. Krieger, Søren Schmidt, M. Davenport, Marin Karuza, I. Ortega, M. J. Pivovaroff, Konstantin Zioutas, C. J. Hailey, J. Ruz, S. Neff, L. Miceli, T. Papaevangelou, S. Aune, Georg G. Raffelt, T. Dafni, I. Savvidis, M. Vretenar, Klaus Kurt Desch, Biljana Lakić, A. Liolios, Georgios Fanourakis, Nenad Kralj, Alexander Dermenev, J. F. Castel, A. Belov, Krešimir Jakovčić, L. Stewart, Dieter Hoffmann, Sami K. Solanki, Heinrich Bräuninger, Serkant Ali Cetin, E. Ruiz Chóliz, F.J. Iguaz, Vassilis Anastassopoulos, H. Fischer, A. Gardikiotis, Yannis K. Semertzidis, M. D. Hasinoff, C. Eleftheriadis, Jochen Kaminski, Anders Clemen Jakobsen, K. Paraschou, E. Ferrer-Ribas, J. M. Carmona, Julia Vogel, Theodoros Vafeiadis, J. G. Garza, K. Barth, G. Luzón, Walter Wuensch, I. Giomataris, M. Rosu, P. Brax, Ante Ljubičić, J. M. Laurent, J. A. Garcia, Evangelos Gazis, Finn Erland Christensen, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Théorique - UMR CNRS 3681 (IPHT), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), CAST, Anastassopoulos, V., Aune, S., Barth, K., Belov, A., Bräuninger, H., Cantatore, G., Carmona, J. M., Castel, J. F., Cetin, S. A., Christensen, F., Dafni, T., Davenport, M., Dermenev, A., Desch, K., Döbrich, B., Eleftheriadis, C., Fanourakis, G., Ferrer-Ribas, E., Fischer, H., Funk, W., García, J. A., Gardikiotis, A., Garza, J. G., Gazis, E. N., Geralis, T., Giomataris, I., Gninenko, S., Hailey, C. J., Hasinoff, M. D., Hoffmann, D. H. H., Iguaz, F. J., Irastorza, I. G., Jakobsen, A., Jacoby, J., Jakovčić, K., Kaminski, J., Karuza, M., Kostoglou, S., Kralj, N., Krčmar, M., Krieger, C., Lakić, B., Laurent, J. M., Liolios, A., Ljubičić, A., Luzón, G., Maroudas, M., Miceli, L., Neff, S., Ortega, I., Papaevangelou, T., Paraschou, K., Pivovaroff, M. J., Raffelt, G., Rosu, M., Ruz, J., Chóliz, E. Ruiz, Savvidis, I., Schmidt, S., Semertzidis, Y. K., Solanki, S. K., Stewart, L., Vafeiadis, T., Vogel, J. K., Vretenar, M., Wuensch, W., Yildiz, S. C., Zioutas, K., and Brax, P.

Subjects
Physics - Instrumentation and Detectors, Photon, Physics::Instrumentation and Detectors, Solar luminosity, magnetic field, Astrophysics, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), photon: coupling, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Astrophysics::Solar and Stellar Astrophysics, Detectors and Experimental Techniques, GridPix, dark energy, modified gravity, physics.ins-det, Solar physics, Physics, dark energy experiments, particle physics - cosmology connection, solar physics, Astronomy and Astrophysics, chameleon: solar, solar physic, Instrumentation and Detectors (physics.ins-det), Coupling (probability), transition: (axion photon), dark energy experiment, Beta (plasma physics), Physics::Space Physics, CAST, Astrophysics::Earth and Planetary Astrophysics, CERN Axion Solar Telescope, Particle Physics - Experiment, chameleon, Modified gravity, Particle physics, CERN Lab, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, photon: spectrum, coupling constant: upper limit, Tachocline, Astrophysics::Cosmology and Extragalactic Astrophysics, X-ray, Dark energy experiments, 0103 physical sciences, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Sensitivity (control systems), hep-ex, background, 010308 nuclear & particles physics, magnet, coupling: (axion 2photon), Particle physics - cosmology connection, axion: solar, tachocline, Energy (signal processing), experimental results
Abstract

We report on a new search for solar chameleons with the CERN Axion Solar Telescope (CAST). A GridPix detector was used to search for soft X-ray photons in the energy range from 200 eV to 10 keV from converted solar chameleons. No signiffcant excess over the expected background has been observed in the data taken in 2014 and 2015. We set an improved limit on the chameleon photon coupling, $\beta_\gamma < 5.7\times10^{10}$ for $1, Comment: 19 pages, 12 figures, 3 tables

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333. New Upper Limit on the Axion-Photon Coupling with an Extended CAST Run with a Xe-Based Micromegas Detector.

Author

Altenmüller K, Anastassopoulos V, Arguedas-Cuendis S, Aune S, Baier J, Barth K, Bräuninger H, Cantatore G, Caspers F, Castel JF, Çetin SA, Christensen F, Cogollos C, Dafni T, Davenport M, Decker TA, Desch K, Díez-Ibáñez D, Döbrich B, Ferrer-Ribas E, Fischer H, Funk W, Galán J, García JA, Gardikiotis A, Giomataris I, Golm J, Hailey CH, Hasinoff MD, Hoffmann DHH, Irastorza IG, Jacoby J, Jakobsen AC, Jakovčić K, Kaminski J, Karuza M, Kostoglou S, Krieger C, Lakić B, Laurent JM, Luzón G, Malbrunot C, Margalejo C, Maroudas M, Miceli L, Mirallas H, Navarro P, Obis L, Özbey A, Özbozduman K, Papaevangelou T, Pérez O, Pivovaroff MJ, Rosu M, Ruiz-Chóliz E, Ruz J, Schmidt S, Schumann M, Semertzidis YK, Solanki SK, Stewart L, Vafeiadis T, Vogel JK, and Zioutas K

Abstract

Hypothetical axions provide a compelling explanation for dark matter and could be emitted from the hot solar interior. The CERN Axion Solar Telescope has been searching for solar axions via their back conversion to x-ray photons in a 9-T 10-m long magnet directed toward the Sun. We report on an extended run with the International Axion Observatory pathfinder detector, doubling the previous exposure time. The detector was operated with a xenon-based gas mixture for part of the new run, providing technical insights for future configurations. No counts were detected in the 95% signal-encircling region during the new run, while 0.75 were expected. The new data improve the axion-photon coupling limit to 5.8×10^{-11}  GeV^{-1} at 95% CL (for m&#95;{a}≲0.02  eV), the most restrictive experimental limit to date.

Published
2024
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334. Search for Invisible Decays of Sub-GeV Dark Photons in Missing-Energy Events at the CERN SPS.

Author

Banerjee D, Burtsev V, Cooke D, Crivelli P, Depero E, Dermenev AV, Donskov SV, Dubinin F, Dusaev RR, Emmenegger S, Fabich A, Frolov VN, Gardikiotis A, Gninenko SN, Hösgen M, Kachanov VA, Karneyeu AE, Ketzer B, Kirpichnikov DV, Kirsanov MM, Kovalenko SG, Kramarenko VA, Kravchuk LV, Krasnikov NV, Kuleshov SV, Lyubovitskij VE, Lysan V, Matveev VA, Mikhailov YV, Myalkovskiy VV, Peshekhonov VD, Peshekhonov DV, Petuhov O, Polyakov VA, Radics B, Rubbia A, Samoylenko VD, Tikhomirov VO, Tlisov DA, Toropin AN, Trifonov AY, Vasilishin B, Vasquez Arenas G, Ulloa P, Zhukov K, and Zioutas K

Abstract

We report on a direct search for sub-GeV dark photons (A^{'}), which might be produced in the reaction e^{-}Z→e^{-}ZA^{'} via kinetic mixing with photons by 100 GeV electrons incident on an active target in the NA64 experiment at the CERN SPS. The dark photons would decay invisibly into dark matter particles resulting in events with large missing energy. No evidence for such decays was found with 2.75×10^{9} electrons on target. We set new limits on the γ-A^{'} mixing strength and exclude the invisible A^{'} with a mass ≲100  MeV as an explanation of the muon g&#95;{μ}-2 anomaly.

Published
2017
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335. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

Author

Arik M, Aune S, Barth K, Belov A, Borghi S, Bräuninger H, Cantatore G, Carmona JM, Cetin SA, Collar JI, Da Riva E, Dafni T, Davenport M, Eleftheriadis C, Elias N, Fanourakis G, Ferrer-Ribas E, Friedrich P, Galán J, García JA, Gardikiotis A, Garza JG, Gazis EN, Geralis T, Georgiopoulou E, Giomataris I, Gninenko S, Gómez H, Gómez Marzoa M, Gruber E, Guthörl T, Hartmann R, Hauf S, Haug F, Hasinoff MD, Hoffmann DH, Iguaz FJ, Irastorza IG, Jacoby J, Jakovčić K, Karuza M, Königsmann K, Kotthaus R, Krčmar M, Kuster M, Lakić B, Lang PM, Laurent JM, Liolios A, Ljubičić A, Luzón G, Neff S, Niinikoski T, Nordt A, Papaevangelou T, Pivovaroff MJ, Raffelt G, Riege H, Rodríguez A, Rosu M, Ruz J, Savvidis I, Shilon I, Silva PS, Solanki SK, Stewart L, Tomás A, Tsagri M, van Bibber K, Vafeiadis T, Villar J, Vogel JK, Yildiz SC, and Zioutas K

Abstract

The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. 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 gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

Published
2014
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336. Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas.

Author

Arik M, Aune S, Barth K, Belov A, Borghi S, Bräuninger H, Cantatore G, Carmona JM, Cetin SA, Collar JI, Dafni T, Davenport M, Eleftheriadis C, Elias N, Ezer C, Fanourakis G, Ferrer-Ribas E, Friedrich P, Galán J, García JA, Gardikiotis A, Gazis EN, Geralis T, Giomataris I, Gninenko S, Gómez H, Gruber E, Guthörl T, Hartmann R, Haug F, Hasinoff MD, Hoffmann DH, Iguaz FJ, Irastorza IG, Jacoby J, Jakovčić K, Karuza M, Königsmann K, Kotthaus R, Krčmar M, Kuster M, Lakić B, Laurent JM, Liolios A, Ljubičić A, Lozza V, Lutz G, Luzón G, Morales J, Niinikoski T, Nordt A, Papaevangelou T, Pivovaroff MJ, Raffelt G, Rashba T, Riege H, Rodríguez A, Rosu M, Ruz J, Savvidis I, Silva PS, Solanki SK, Stewart L, Tomás A, Tsagri M, van Bibber K, Vafeiadis T, Villar JA, Vogel JK, Yildiz SC, and Zioutas K

Abstract

The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. 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(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

Published
2011
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337. Searching for decaying axionlike dark matter from clusters of galaxies.

Author

Riemer-Sørensen S, Zioutas K, Hansen SH, Pedersen K, Dahle H, and Liolios A

Abstract

We constrain the lifetime of radiatively decaying dark matter in clusters of galaxies inspired by generic Kaluza-Klein axions, which have been invoked as a possible explanation for the solar coronal x-ray emission. These particles can be produced inside stars and remain confined by the gravitational potential of clusters. By analyzing x-ray observations of merging clusters, where gravitational lensing observations have identified massive, baryon poor structures, we derive the first cosmological lifetime constraint on this kind of particles of tau > or = 10(23) sec.

Published
2007
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