A. Liolios
A5041748300- Particle physics theoretical and experimental studies
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Muon and positron interactions and applications
- Radiation Detection and Scintillator Technologies
- Cosmology and Gravitation Theories
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Black Holes and Theoretical Physics
- Physics of Superconductivity and Magnetism
- Glass properties and applications
- Silicon and Solar Cell Technologies
- Particle accelerators and beam dynamics
- Metallic Glasses and Amorphous Alloys
- Distributed and Parallel Computing Systems
- Computational Physics and Python Applications
- Gamma-ray bursts and supernovae
- Magnetic Properties of Alloys
- Photocathodes and Microchannel Plates
Aristotle University of Thessaloniki
2010-2020
Deutsche Gesellschaft für Information und Wissen
1992
Max Planck Institute for Solid State Research
1992
University of Göttingen
1992
InLeaVe
1992
University of Macedonia
1990
Hypothetical low-mass particles, such as axions, provide a compelling explanation for the dark matter in universe. Such particles are expected to emerge abundantly from hot interior of stars. To test this prediction, CERN Axion Solar Telescope (CAST) uses 9 T refurbished Large Hadron Collider magnet directed towards Sun. In strong magnetic field, solar axions can be converted X-ray photons which recorded by detectors. 2013–2015 run, thanks low-background detectors and new telescope,...
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 absence of excess X-rays when magnet was pointing Sun, we set an upper limit on axion-photon coupling 8.8 x 10^{-11} GeV^{-1} at 95% CL m_a <~ 0.02 eV. This result is best experimental over a broad range axion masses and eV also supersedes previous derived from energy-loss arguments globular-cluster stars.
The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO look for axions or axion-like particles (ALPs) originating in the Sun via Primakoff conversion of solar plasma photons. In terms signal-to-noise ratio, about 4–5 orders magnitude more sensitive than CAST, currently most powerful helioscope, reaching sensitivity to axion-photon couplings down few × 10−12 GeV−1 and thus probing large fraction unexplored ALP parameter space....
Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by Primakoff process. In laboratory magnetic field ("axion helioscope"), they transformed into x-rays energies of few keV. Using decommissioned Large Hadron Collider test magnet, CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from analysis these data are presented here. No signal above background was observed, implying an upper limit to axion-photon coupling...
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 reported results from CAST with evacuated magnet bores (Phase I), setting limits on lower mass axions, here report where were filled 4He gas II) of variable pressure. The introduction generates a refractive photon mγ, thereby achieving maximum possible conversion rate those axion masses ma match mγ. With 160 different...
The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With about 1 h of data taking at each 252 different we have scanned the mass range 0.39 eV < m_a 0.64 eV. From absence excess X-rays when magnet was pointing Sun set typical upper limit on axion-photon coupling g_ag 2.3 x 10^{-10} GeV^{-1} 95% CL, exact...
The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the range 0.64 eV ≲ ma 1.17 eV. This closes gap to cosmological hot dark matter limit and actually overlaps it. From absence of excess x rays when magnet was pointing Sun we set a typical upper on axion-photon coupling gaγ 3.3 × 10(-10) GeV(-1) at 95% C.L., exact value depending pressure setting. Future direct axion searches will focus increasing sensitivity smaller values gaγ, example by...
In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces strong flux by bremsstrahlung, Compton scattering, and axio-recombination, ``BCA processes.'' Based on new calculation of this flux, including for first time we derive limits Yukawa coupling gae axion-photon interaction strength gaγ using CAST phase-I data (vacuum phase). For ma≲10 meV/c2 find < 8.1 × 10−23 GeV−1 at 95% CL. We stress that next-generation helioscope such as proposed IAXO could...
The CERN Axion Solar Telescope (CAST) searches for $a\ensuremath{\rightarrow}\ensuremath{\gamma}$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward Sun. Two parallel bores filled with helium adjustable pressure to match x-ray refractive mass ${m}_{\ensuremath{\gamma}}$ axion search ${m}_{a}$. After vacuum phase (2003--2004), which is optimal ${m}_{a}\ensuremath{\lesssim}0.02\text{ }\text{ }\mathrm{eV}$, we used $^{4}\mathrm{He}$ 2005--2007...
We use fits to recent published CPLEAR data on neutral kaon decays $π^+π^-$ and $πeν$ constrain the CPT--violation parameters appearing in a formulation of system as an open quantum-mechanical system. The obtained upper limits are approaching range suggested by certain ideas concerning quantum gravity.
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 axion-to-photon conversion CERN Axion Solar Telescope (CAST) with evacuated magnet bores (Phase I). From absence excess monoenergetic X-rays when was pointing to Sun, we set model-independent constraints on coupling constants pseudoscalar couple two photons and a nucleon gaγ|−1.19gaN0+gaN3| < 1.36 × 10−16 GeV−1 ma 0.03 eV at 95% confidence level.
In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in field of dark energy research, exploits both chameleon coupling to matter (βm) and photons (βγ) via Primakoff effect. By reducing X-ray detection threshold used axions from 1 keV 400 eV CAST became sensitive converted solar spectrum which peaks around 600 eV. Even though have not observed any excess above background, can provide 95% C.L. limit strength...
The International Axion Observatory (IAXO) is a next generation axion helioscope aiming at sensitivity to the axion-photon coupling of few 10^{-12} GeV^{-1}, i.e. 1-1.5 orders magnitude beyond sensitivities achieved by currently most sensitive helioscope, CERN Solar Telescope (CAST). Crucial factors in improving for IAXO are increase magnetic field volume together with extensive use x-ray focusing optics and low background detectors, innovations already successfully tested CAST....
The CP violation parameter η+− is determined through the eigentime-dependent asymmetry in rates of initially tagged K0 and decaying to π+π−. obtained values are |η+−| = (2.312 ± 0.043stat. 0.030syst. 0.011τs) × 10−3 Φ+− 42.7° 0.9stat.° 0.6syst.° 0.9Δm° with Δ (527.4 2.9) 107h̵gs−1 measured same experiment using semileptonic decay channel.
We present the results of a search for high-energy axion emission signal from 7Li (0.478 MeV) and D(p,gamma)3He (5.5 nuclear transitions using low-background gamma-ray calorimeter during Phase I CAST experiment. These so-called "hadronic axions" could provide solution to long-standing strong-CP problem can be emitted solar core M1 transitions. This is first such pseudoscalar bosons with couplings nucleons conducted helioscope approach. No excess above background was found.
The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at sensitivity to the axion-photon coupling of gaγ ≳ few × 10−12 GeV−1, i.e. 1–1.5 orders magnitude beyond one achieved by CAST, currently most sensitive helioscope. main elements IAXO are an increased magnetic field volume together with extensive use x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases could include detection...
The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 – 10 keV energies in strong magnetic field. IAXO will achieve sensitivity axion-photon coupling gaγ down few ×10−12 GeV−1 wide range masses up ∼ 0.25 eV. This an improvement over currently best (3rd generation) helioscope, CERN Solar Telescope (CAST), about 5 orders magnitude signal...