Alexander Dermenev
A5061624991- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Neutrino Physics Research
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Distributed and Parallel Computing Systems
- Gamma-ray bursts and supernovae
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Nuclear physics research studies
- International Science and Diplomacy
- Magnetic confinement fusion research
- Noncommutative and Quantum Gravity Theories
- Radioactivity and Radon Measurements
- Stochastic processes and financial applications
- Particle accelerators and beam dynamics
- Big Data Technologies and Applications
European Organization for Nuclear Research
2014-2025
ETH Zurich
2024
Institute for Nuclear Research
2012-2022
Russian Academy of Sciences
2011
Lomonosov Moscow State University
2007
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,...
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...
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...
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...
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...
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...
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...
We report the first search for dark sectors performed at NA64 experiment employing a high energy muon beam and missing energy-momentum technique. Muons from M2 beamline CERN Super Proton Synchrotron with momentum of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mn>160</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>GeV</a:mi><a:mo>/</a:mo><a:mi>c</a:mi></a:mrow></a:math> are directed to an active target. The signal signature consists single scattered...
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...
A search for a new Z^{'} gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out first time using missing-energy technique NA64 experiment at CERN SPS. From analysis of data 3.22×10^{11} electrons on target collected during 2016-2021 runs, no signal events were found. This allows us to derive constraints Z^{'}-e coupling strength, which, 0.3≲m_{Z^{'}}≲100 MeV, are more stringent compared those obtained from neutrino-electron scattering data.
A bstract The inclusion of an additional U(1) gauge L μ − τ symmetry would release the tension between measured and predicted value anomalous muon magnetic moment: this paradigm assumes existence a new, light Z ′ vector boson, with dominant coupling to leptons interacting electrons via loop mechanism. model can also explain Dark Matter relic abundance, by assuming that boson acts as “portal” new Sector particles in Nature, not charged under known interactions. In work we present results...
Thermal light dark matter (LDM) with particle masses in the 1 MeV - GeV range could successfully explain observed abundance as a relic from primordial Universe. In this picture, new feeble interaction acts "portal" between Standard Model and LDM particles, allowing for exploration of paradigm at accelerator experiments. last years, "missing energy" experiment NA64e CERN SPS (Super Proton Synchrotron) has set world-leading constraints vector-mediated parameter space, by exploiting 100...
Liquid Argon Time Projection Chamber (LAr TPC) detectors offer charged particle imaging capability with remarkable spatial resolution. Precise event reconstruction procedures are critical in order to fully exploit the potential of this technology. In paper we present a new, general approach 3D for LAr TPC practical application track reconstruction. The efficiency method is evaluated on sample simulated tracks. We also analysis stopping tracks collected during ICARUS T600 detector operation...
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...
We performed a search for new generic $X$ boson, which could be scalar ($S$), pseudoscalar ($P$), vector ($V$), or an axial ($A$) particle produced in the 100 GeV electron scattering off nuclei, ${e}^{\ensuremath{-}}Z\ensuremath{\rightarrow}{e}^{\ensuremath{-}}ZX$, followed by its invisible decay NA64 experiment at CERN. No evidence such process was found full dataset of $2.84\ifmmode\times\else\texttimes\fi{}{10}^{11}$ electrons on target. place bounds $S$, $P$, $V$, $A$ coupling strengths...
The OPERA collaboration has claimed evidence of superluminal {\nu}{_\mu} propagation between CERN and the LNGS. Cohen Glashow argued that such neutrinos should lose energy by producing photons e+e- pairs, through Z0 mediated processes analogous to Cherenkov radiation. In terms parameter delta=(v^2_nu-v^2_c)/v^2_c, result implies delta = 5 x 10^-5. For this value \delta a very significant deformation neutrino spectrum an abundant production pairs be observed at We present analysis based on...
The extension of Standard Model made by inclusion additional $U(1)$ gauge ${L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}$ symmetry can explain the difference between measured and predicted value muon magnetic moment solve tension in $B$ meson decays. This model predicts existence a new, light ${Z}^{\ensuremath{'}}$ vector boson, predominantly coupled to second third generation leptons, whose interaction with electrons is due loop mechanism involving muons taus. In this work, we...
We present the results of a missing-energy search for light dark matter which has new interaction with ordinary transmitted by vector boson, called photon <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>A</a:mi><a:mo>′</a:mo></a:msup></a:math>. For first time, this is performed positron beam using significantly enhanced production <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mi>A</c:mi><c:mo>′</c:mo></c:msup></c:math> in...
We report the results of a search for light pseudoscalar particle $a$ that couples to electrons and decays ${e}^{+}{e}^{\ensuremath{-}}$ performed using high-energy CERN SPS H4 electron beam. If such exists, it could explain ATOMKI anomaly (an excess pairs in nuclear transitions $^{8}\mathrm{Be}$ $^{4}\mathrm{He}$ nuclei at invariant mass $\ensuremath{\simeq}17\text{ }\text{ }\mathrm{MeV}$ observed by experiment 5 MV Van de Graaff accelerator ATOMKI, Hungary). used NA64 data collected...
Abstract We report the results of a search for new vector boson ( $$ A'$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>A</mml:mi> <mml:mo>′</mml:mo> </mml:msup> </mml:math> ) decaying into two dark matter particles $$\chi _1 \chi _2$$ <mml:mrow> <mml:msub> <mml:mi>χ</mml:mi> <mml:mn>1</mml:mn> </mml:msub> <mml:mn>2</mml:mn> </mml:mrow> different mass. The heavier particle subsequently decays to _1$$ and an off-shell Dark Photon A'^* \rightarrow e^+e^-$$...
This proposal describes an experimental search for sterile neutrinos beyond the Standard Model with a new CERN-SPS neutrino beam. The experiment is based on two identical LAr-TPC's followed by magnetized spectrometers, observing electron and muon events at 1600 300 m from proton target. project will exploit ICARUS T600, moved LNGS to CERN "Far" position. An additional 1/4 of T600 detector be constructed located in "Near" Two spectrometers placed downstream LAr-TPC detectors greatly...
In high energy experiments such as active beam dump searches for rare decays and missing events, the purity is a crucial parameter. this paper we present technique to reject heavy charged particle contamination in 100 GeV electron of H4 line at CERN SPS. The method based on detection with BGO scintillators synchrotron radiation emitted by electrons passing through bending dipole magnet. A π− used test NA64 experiment resulting suppression factor 10−5 while efficiency ∼95%. spectra rejection...