H. Fischer
A5075802195- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Advancements in PLL and VCO Technologies
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Quantum, superfluid, helium dynamics
- Radiation Detection and Scintillator Technologies
- Neutrino Physics Research
- Nuclear physics research studies
- Photocathodes and Microchannel Plates
- Strong Light-Matter Interactions
- Opportunistic and Delay-Tolerant Networks
- Scientific Research and Discoveries
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Radiation Effects in Electronics
- Medical Imaging Techniques and Applications
- Advanced Power Amplifier Design
- Adaptive optics and wavefront sensing
University of Freiburg
2010-2024
University of Fribourg
2024
Charles University
2024
A. Alikhanyan National Laboratory
2023
University of Aveiro
2019-2020
European Organization for Nuclear Research
2017-2020
Paul Scherrer Institute
2010
Institute for Mobile and Satellite Communication Technology
2004
University of New Mexico
2003
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.
We present the first measurement of nuclear recoils from solar <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mmultiscripts><a:mrow><a:mi mathvariant="normal">B</a:mi></a:mrow><a:mprescripts/><a:none/><a:mrow><a:mn>8</a:mn></a:mrow></a:mmultiscripts></a:mrow></a:math> neutrinos via coherent elastic neutrino-nucleus scattering with XENONnT dark matter experiment. The central detector is a low-background, two-phase time projection chamber 5.9 t sensitive...
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...
Results are reported from the HERMES experiment at HERA on a measurement of neutron spin structure function $g_1^n(x,Q^2)$ in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident $^3$He internal gas target. The data cover kinematic range $0.023
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...
A bstract We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part CERN Solar Telescope (CAST), searching for axion dark matter in 34.67 μ eV mass range. radio frequency cavity consisting 5 sub-cavities coupled by inductive irises took physics data inside CAST dipole magnet first time using this filter-like haloscope geometry. An exclusion limit with 95% credibility level on axion-photon coupling constant g aγ ≳ 4 × 10 − 13 GeV 1 over range 34 ....
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in 19.74 $\mu$eV to 22.47 mass range. detection concept follows Sikivie haloscope principle, where Dark Matter convert into photons within a resonator immersed magnetic field. is an array of four individual rectangular cavities inserted strong phase-matched maximize sensitivity. Here we report on data acquired 4124 h from 2019 2021. Each cavity equipped with fast frequency tuning mechanism...
The multi-staged XENON program at INFN Laboratori Nazionali del Gran Sasso aims to detect dark matter with two-phase liquid xenon time projection chambers of increasing size and sensitivity. XENONnT experiment is the latest detector in program, planned be an upgrade its predecessor XENON1T. It features active target 5.9 tonnes cryogenic (8.5 total mass cryostat). expected extend sensitivity WIMP by more than order magnitude compared XENON1T, thanks larger significantly reduced background,...
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...
We report experimental details and results of a new measurement the decay K+→π+π−e+νe(Ke4). A sample more than 400,000Ke4 events with low background has been collected by Experiment 865 at Brookhaven Alternate Gradient Synchrotron. From these data, branching ratio (4.11±0.01±0.11)×10−5 ππ invariant mass dependence form factors F,G, H weak hadronic current as well phase shift difference δ00−δ11 for scattering were extracted. Using constraints based on analyticity chiral symmetry, value...
Abstract On a very fundamental level, particle detectors share similar requirements for their read-out chain. This is reflected in the way that typical solutions are developed, where previous design modified to fit changes requirements. One of two common approaches current-based read-out, waveform sensor output sampled order later extract information central processing unit. approach used many detector applications using scintillation based detectors, including PET. With this contribution,...
The CERN Axion Solar Telescope (CAST) has been in operation and taking data since 2003. main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, axion, which might be produced core sun. basic physics process based on time inverted Primakoff effect, by an axion can converted into detectable photon external electromagnetic field. resulting x-ray photons are expected thermally distributed between 1 7 keV. most sensitive detector system pn-CCD combined with...
Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and shown for kinematic range 1(GeV/c)2<Q2<100(GeV/c)2 in photon virtuality, 0.004<x<0.7 Bjorken scaling variable W>4GeV/c2 mass hadronic final state. deuteron double-spin asymmetry A1d longitudinal-spin structure function g1d bins x Q2. Towards lowest accessible values x, decreases becomes...
We discuss the physics case for and concept of a medium-scale axion helioscope with sensitivities in axion-photon coupling few times better than CERN Axion Solar Telescope (CAST). Search an axion-like particle these couplings is motivated by several persistent astrophysical anomalies. present early conceptual design, existing infrastructure, projected sensitivity timeline such (Troitsk Experiment, TASTE) to be constructed Institute Nuclear Research, Troitsk, Russia. The proposed instrument...
We report on a first measurement with sensitive opto-mechanical force sensor designed for the direct detection of coupling real chameleons to matter. These dark energy candidates could be produced in Sun and stream unimpeded Earth. The KWISP detector installed CAST axion search experiment at CERN looks tiny displacements thin membrane caused by mechanical effect solar chameleons. are detected Michelson interferometer homodyne readout scheme. benefits from focusing action ABRIXAS X-ray...
The production of vector mesons in deep inelastic scattering is an interesting yet scarsely explored channel to study the transverse spin structure nucleon and related phenomena. COMPASS collaboration has performed first measurement Collins Sivers asymmetries for inclusively produced $\rho^0$ mesons. analysis based on data set collected $2010$ using a $160\,\,\rm{GeV}/c$ $\mu^+$ beam impinging transversely polarized $\rm{NH}_3$ target. $\rho^{0}$ are selected from oppositely charged hadron...
Abstract As a prototype detector for the SHiP Surrounding Background Tagger (SBT), we constructed cell (120 cm × 80 25 cm) made from corten steel that is filled with liquid scintillator (LS) composed of linear alkylbenzene (LAB) and 2,5-diphenyloxazole (PPO). The equipped two Wavelength-shifting Optical Modules (WOMs) light collection primary scintillation photons. Each WOM consists an acrylic tube dip-coated wavelength-shifting layer on its surface. Via internal total reflection, secondary...
New results are presented on a high-statistics measurement of Collins and Sivers asymmetries charged hadrons produced in deep inelastic scattering muons transversely polarized ^{6}LiD target. The data were taken 2022 with the COMPASS spectrometer using 160 GeV muon beam at CERN, statistically balancing existing proton targets. first from about two-thirds new have total uncertainties smaller by up to factor three compared previous deuteron measurements. Using all results, both transversity...
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 GANDALF 6U-VME64x/VXS module has been designed to cope with a variety of readout tasks in high energy and nuclear physics experiments, particular the COMPASS experiment at CERN. exchangeable mezzanine cards allow for an employment system very different applications such as analog-to-digital or time-to-digital conversions, coincidence matrix formation, fast pattern recognition trigger generation. Based on this platform, we present 128-channel TDC which is implemented single Xilinx...
A set of measurements azimuthal asymmetries in the production pairs identified hadrons deep-inelastic scattering muons on transversely polarised 6LiD (deuteron) and NH3 (proton) targets is presented. All available data collected years 2003–2004 2007/2010 with COMPASS spectrometer using a muon beam 160GeV/c at CERN SPS were analysed. The provide access to transversity distribution functions via fragmentation function that principle may be independently obtained from e+e− annihilation data....
We report on a new search for solar chameleons with the CERN Axion Solar Telescope (CAST). A GridPix detector was used to soft X-ray photons in energy range from 200 eV 10 keV converted chameleons. No signiffcant excess over expected background has been observed data taken 2014 and 2015. set an improved limit chameleon photon coupling, $\beta_\gamma < 5.7\times10^{10}$ $1<\beta_\mathrm{m}<10^6$ at 95% C.L. improving our previous results by factor two first time reaching sensitivity below...