S. Gninenko
A5035658746- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Neutrino Physics Research
- Computational Physics and Python Applications
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Atomic and Molecular Physics
- Muon and positron interactions and applications
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Medical Imaging Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Cold Atom Physics and Bose-Einstein Condensates
- Black Holes and Theoretical Physics
- Superconducting Materials and Applications
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- CCD and CMOS Imaging Sensors
- Nuclear physics research studies
- Radiation Therapy and Dosimetry
- Quantum and Classical Electrodynamics
European Organization for Nuclear Research
2002-2025
Institute for Nuclear Research
2015-2024
A. Alikhanyan National Laboratory
2022-2024
Millennium Institute
2024
Universidad Andrés Bello
2024
Institute of High Energy Physics
2021-2024
University of Antwerp
2024
Princeton University
2023
Purdue University West Lafayette
2023
Institute for Theoretical and Experimental Physics
2023
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,...
This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and latest astrophysical data.
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....
Abstract With the establishment and maturation of experimental programs searching for new physics with sizeable couplings at LHC, there is an increasing interest in broader particle astrophysics community exploring light feebly-interacting particles as a paradigm complementary to New Physics sector TeV scale beyond. FIPs 2020 has been first workshop fully dedicated was held virtually from 31 August 4 September 2020. The gathered together experts collider, beam dump, fixed target experiments,...
A search for sub-GeV dark matter production mediated by a new vector boson A^{'}, called photon, is performed the NA64 experiment in missing energy events from 100 GeV electron interactions an active beam dump at CERN SPS. From analysis of data collected years 2016, 2017, and 2018 with 2.84×10^{11} electrons on target no evidence such process has been found. The most stringent constraints A^{'} mixing strength photons parameter space scalar fermionic mass range ≲0.2 are derived, thus...
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...
We report on a direct search for sub-GeV dark photons (${A}^{\ensuremath{'}}$), which might be produced in the reaction ${e}^{\ensuremath{-}}Z\ensuremath{\rightarrow}{e}^{\ensuremath{-}}Z{A}^{\ensuremath{'}}$ via kinetic mixing with by 100 GeV electrons incident an active target NA64 experiment at CERN SPS. The would decay invisibly into matter particles resulting events large missing energy. No evidence such decays was found $2.75\ifmmode\times\else\texttimes\fi{}1{0}^{9}$ target. set new...
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...
A search is performed for a new sub-GeV vector boson (${A}^{\ensuremath{'}}$) mediated production of dark matter ($\ensuremath{\chi}$) in the fixed-target experiment, NA64, at CERN SPS. The ${A}^{\ensuremath{'}}$, called photon, can be generated reaction ${e}^{\ensuremath{-}}Z\ensuremath{\rightarrow}{e}^{\ensuremath{-}}Z{A}^{\ensuremath{'}}$ 100 GeV electrons dumped against an active target followed by its prompt invisible decay...
Important open questions are still present in fundamental Physics and Cosmology, like the nature of Dark Matter, matter-antimatter asymmetry validity Standard Model particle interactions. Addressing these requires a new generation massive detectors to explore subatomic astrophysical worlds. ICARUS T600 is first large mass (760 tons) example able combine imaging capabilities old famous ``bubble chamber'' with excellent energy measurement huge electronic detectors. now operates at Gran Sasso...
The 3.6 \sigma discrepancy between the predicted and measured values of anomalous magnetic moment positive muons can be explained by existence a new dark boson Z_\mu with mass in sub-GeV range, which is coupled predominantly to second third lepton generations through L_\mu - L_\tau current . After discussion present phenomenological bounds on coupling, we show that if exists, it could observed reaction \mu+Z \to \mu+Z+Z_\mu muon scattering off nuclei looking for an excess events large...
We report the first results on a direct search for new 16.7 MeV boson (X) which could explain anomalous excess of e^{+}e^{-} pairs observed in excited ^{8}Be^{*} nucleus decays. Because its coupling to electrons, X be produced bremsstrahlung reaction e^{-}Z→e^{-}ZX by 100 GeV e^{-} beam incident an active target NA64 experiment at CERN Super Proton Synchrotron and through subsequent decay into pair. With 5.4×10^{10} electrons target, no evidence such decays was found, allowing us set limits...
We review the physics potential of a next generation search for solar axions: International Axion Observatory (IAXO) . Endowed with sensitivity to discover axion-like particles (ALPs) coupling photons as small gaγ∼ 10−12 GeV−1, or electrons gae∼10−13, IAXO has find QCD axion in 1 meV∼1 eV mass range where it solves strong CP problem, can account cold dark matter Universe and be responsible anomalous cooling observed number stellar systems. At same time, will have enough detect lower axions...
The improved results on a direct search for new X(16.7 MeV) boson which could explain the anomalous excess of $e^+e^-$ pairs observed in excited 8Be nucleus decays ("Berillium anomaly") are reported. Due to its coupling electrons, X be produced bremsstrahlung reaction e-Z -> e-ZX by high-energy beam electrons incident active target NA64 experiment at CERN SPS and through subsequent decay into pair. No evidence such was found from combined analysis data samples with total statistics...
We carried out a model-independent search for light scalar ($s$) and pseudoscalar axionlike ($a$) particles that couple to two photons by using the high-energy CERN SPS H4 electron beam. The new particles, if they exist, could be produced through Primakoff effect in interactions of hard bremsstrahlung generated 100 GeV electrons NA64 active dump with virtual provided nuclei dump. $a(s)$ would penetrate downstream HCAL module, serving as shield, observed either their...
A bstract This article describes BabyIAXO, an intermediate experimental stage of the International Axion Observatory (IAXO), proposed to be sited at DESY. IAXO is a large-scale axion helioscope that will look for axions and axion-like particles (ALPs), produced in Sun, with unprecedented sensitivity. BabyIAXO conceived test all subsystems (magnet, optics detectors) relevant scale final system thus serve as prototype IAXO, but same time fully-fledged physics reach itself, potential discovery....
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...
Thermal dark matter models with particle χ masses below the electroweak scale can provide an explanation for observed relic density. This would imply existence of a new feeble interaction between and ordinary matter. We report on search sub-GeV production through mediated by vector boson, called photon A^{'}, in collisions 100 GeV electrons active target NA64 experiment at CERN SPS. With 9.37×10^{11} collected during 2016-2022 runs probes first time well-motivated region parameter space...