V. Petousis
A5002926510- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Cosmology and Gravitation Theories
- Neutrino Physics Research
- Pulsars and Gravitational Waves Research
- Distributed and Parallel Computing Systems
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Medical Imaging Techniques and Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Black Holes and Theoretical Physics
- Astrophysics and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Solar and Space Plasma Dynamics
- Advanced Data Storage Technologies
- Digital Radiography and Breast Imaging
- Particle Accelerators and Free-Electron Lasers
- Big Data Technologies and Applications
- High-pressure geophysics and materials
- Ionosphere and magnetosphere dynamics
Czech Technical University in Prague
2020-2025
Brandeis University
2022-2024
A. Alikhanyan National Laboratory
2024
SR Research (Canada)
2024
Federación Española de Enfermedades Raras
2024
Atlas Scientific (United States)
2024
The University of Adelaide
2021-2023
Centre National de la Recherche Scientifique
2023
University of California, Santa Cruz
2023
Aix-Marseille Université
2023
We present a search for the e+e− decay of hypothetical dark photon, also named U vector boson, in inclusive dielectron spectra measured by HADES p(3.5 GeV) + p, Nb reactions, as well Ar (1.756 GeV/u) KCl reaction. An upper limit on kinetic mixing parameter squared ϵ2 at 90% CL has been obtained mass range MU=0.02–0.55 GeV/c2 and is compared with world data set. For masses 0.03–0.1 GeV/c2, lowered respect to previous results, allowing now exclude large part region favored muon g−2 anomaly....
Abstract The workshop “Shedding light on X17” brings together scientists looking for the existence of a possible new particle, often referred to as X17. This hypothetical particle can explain resonant structure observed at $$\sim $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> </mml:math> 17 MeV in invariant mass electron-positron pairs, produced after excitation nuclei such $$^8\hbox {Be}$$ <mml:mrow> <mml:msup> <mml:mrow /> <mml:mn>8</mml:mn> </mml:msup>...
We investigate the hypothetical X17 boson on neutron stars and quark (QSs) using various hadronic equation of states (EoSs) with phenomenological or microscopic origin. Our aim is to set realistic constraints its coupling constant mass scaling, respect causality possible upper limits dimensionless tidal deformability ${\mathrm{\ensuremath{\Lambda}}}_{1.4}$. In particular, we pay special attention two main parameters X17, one related $\mathrm{g}$ that it has hadrons quarks other in-medium...
Until today, the nature of dark matter (DM) remains elusive despite all our efforts. This missing Universe has not been observed by already operating DM direct-detection experiments, but we can infer its gravitational effects. Galaxies and clusters galaxies are most likely to contain trapped their field. leads us natural assumption that compact objects might too. Among exist in galaxies, neutron stars considered as laboratories, where theories be tested, observational data received. Thus,...
We report on the first measurement of $p\mathrm{\ensuremath{\Lambda}}$ and $pp$ correlations via femtoscopy method in $p$ + Nb reactions at $\sqrt{{s}_{\mathit{NN}}}=3.18\phantom{\rule{0.28em}{0ex}}\mathrm{GeV}$, studied with High Acceptance Di-Electron Spectrometer (HADES). By comparing experimental correlation function to model calculations, a source size for pairs...
We report on the investigation of $\mathrm{\ensuremath{\Delta}}$(1232) production and decay in proton-proton collisions at a kinetic energy 1.25 GeV measured with HADES. Exclusive dilepton channels $pp{e}^{+}{e}^{\ensuremath{-}}$ $pp{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$ have been studied compared partial-wave analysis hadronic $pp{\ensuremath{\pi}}^{0}$ channel. They allow to access both...
We present a search for the e+e- decay of hypothetical dark photon, also names U vector boson, in inclusive dielectron spectra measured by HADES p (3.5 GeV) + p, Nb reactions, as well Ar (1.756 GeV/u) KCl reaction. An upper limit on kinetic mixing parameter squared epsilon^{2} at 90% CL has been obtained mass range M(U) = 0.02 - 0.55 GeV/c2 and is compared with world data set. For masses 0.03 0.1 GeV/c^2, lowered respect to previous results, allowing now exclude large part region favoured...
Fission barrier heights of short-lived nuclei away from line $\ensuremath{\beta}$ stability are not known reliably. Low-energy fission $^{210}\mathrm{Fr}$ and $^{210}\mathrm{Ra}$, produced by ($d,p$) ($d,n$) transfer reaction on the re-accelerated unstable beam $^{209}\mathrm{Fr}$ was investigated at HIE-ISOLDE. Four Timepix3 pixel detectors were installed body ACTAR TPC demonstrator chamber. Polyethylene converters used for detection fast neutrons. Since no significant background observed,...
Till today, the nature of dark matter remains elusive despite all our efforts. This missing universe has not been observed by already operating direct-detection exper- iments, but we can infer its gravitational effects. Galaxies and clusters galaxies are most likely to contain trapped their field. leads us natural assumption that compact objects might too. Among exist in galaxies, neutron stars considered as laboratories, where theories be tested, observational data received. Thus, many...
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam kinetic energy 1.25GeV/u impinging liquid hydrogen target. Our measurements with HADES confirm significant excess $e^{+}e^{-}$ pairs above $\pi^{0}$ mass exclusive channel $dp \rightarrow npe^{+}e^{-}(p_{spect})$ as compared to $ ppe^{+}e^{-}$ measured proton-proton at same energy. That points different bremsstrahlung mechanisms. Two models were evaluated for role...
The inclusive production of {\Lambda} hyperons in proton-proton collisions at $\sqrt{s}$ = 3.18 GeV was measured with HADES the GSI Helmholtzzentrum f\"ur Schwerionenforschung Darmstadt. experimental data are compared to a data-based model for individual exclusive channels same reaction. contributions intermediate resonances such as {\Sigma}(1385), {\Delta}++ or N* considered detail. In particular, result partial wave analysis is accounted abundant pK$^+${\Lambda} final state. Model and show...
The HADES collaboration uses the e + − production as a probe of resonance matter produced in collisions at incident energies 1-3.5 GeV/nucleon GSI. Elementary reactions provide useful references for these studies and give information on Dalitz decays (R→Ne ). Such processes are sensitive to structure time-like electromagnetic baryon transitions kinematic range where (off-shell) vector mesons play crucial role. Results obtained proton-proton commissioning pion-beam experiment reported...
The production of $\Sigma^{0}$ baryons in the nuclear reaction p (3.5 GeV) + Nb (corresponding to $\sqrt{s_{NN}}=3.18$ is studied with detector set-up HADES at GSI, Darmstadt. $\Sigma^{0}$s were identified via decay $\Sigma^{0} \rightarrow \Lambda \gamma$ subsequent decays $\Lambda \pi^{-}$ coincidence a $e^{+}e^{-}$ pair from either external ($\gamma e^{+} e^{-}$) or internal (Dalitz $\gamma^{*}\rightarrow gamma conversions. differential $\Sigma^0$ cross section integrated over acceptance,...
This work presents the analysis of performance RPC ToF wall HADES, located at GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. The behavior detector is studied in Au+Au collisions 1.23 AGeV. A main characteristic that all active areas were designed to be electrically shielded order operate high occupancies chambers. Here we show achieved regarding efficiency and timing capabilities different this special design after applied offline corrections data. Also stability intrinsic time...
We present a hypothesis that the anomaly in folding angle distribution of electron-positron pairs, emitted decay excited levels nucleus $^{8}$Be and $^{4}$He can be related to cluster structure decaying state. Furthermore, we potentially observed boson with re st mass $m_{X}$=17 MeV mediate nucleon-nucleon interaction at low-energy regime QCD, particular weakly bound state p+$^{7}$Li,$^{3}$H. possible equations symmetric nuclear matter corresponding vector meson $m_{v}$=17 MeV, obtained...
Within the scope of Symmetry journal special issue on: “The Nuclear Physics Neutron Stars”, we complemented nuclear equation state (EoS) with a hypothetical 17 MeV boson and observed that only instances an admixture 30%–40% satisfy all constraints. The successful EoS resulted in radius around 13 km for neutron star mass MNS≈1.4M⊙ maximum MNS≈2.5M⊙. value is agreement recent measurement by NICER. also remnant gravitational wave event GW190814. Thus, it appears these EoSs existing experimental...
We present and discuss recent experimental activities of the HADES collaboration on open hidden strangeness production close or below elementary NN threshold. Special emphasis is put feed-down from ϕ mesons to antikaons, presence Ξ- excess in cold nuclear matter comparison statistical model rates p+p data. The implications for interpretation heavy-ion data are discussed as well.
The recent observation of the compact star XTE J1814-338 with a mass $M=1.2^{+0.05}_{-0.05}~{\rm M_{\odot}}$ and radius $R=7^{+0.4}_{-0.4}$ km, together HESS J1731-347, which has $M=0.77^{+0.20}_{-0.17}~{\rm $R=10.4^{+0.86}_{-0.78}$ they provide evidence for possible presence exotic matter in core neutron stars significantly enhance our understanding equation state dense nuclear matter. In present srtudy, we investigate existence neutral anti-kaons negative charged kaons by employing...
We examine the hypothetical X17 boson on neutron stars and quark using various hadronic equations of state with phenomenological or microscopic origin. Our aim is to set realistic constraints its coupling constant mass scaling. Everything done respect causality possible upper limits dimensionless tidal deformability Λ 1.4 . focused two main parameters, g that it has hadrons quarks in-medium effects through regulator C. came general conclusion effect both constrained mainly by limit, which a...
To this day, the nature of dark matter (DM) remains elusive despite all our efforts. This type has not been directly observed, so we infer its gravitational effect. Since galaxies and supermassive objects like these are most likely to contain DM, assume that dense such as neutron stars (NSs) also host DM. The NS is considered best natural laboratory for testing theories collecting observational data. We mainly focus on two types DM particles, fermions bosons, with a mass range [0.01–1.5] GeV...
The recent observation of a compact star with the lowest observable mass 0.77 +0.20 –0.17 M ⊙ within supernova remnant HESS J1731-347 has redefined our understanding for dense nuclear matter equation state and enhances existence exotic matter. In present work, we investigate possible kaon condensation in hadronic neutron stars through framework Momentum-Dependent Interaction model describing We concentrate on strangeness content proton its implications both microscopic macroscopic properties...
Neutron stars and black holes are the after death remnants of massive stars. However, according to most recent observations, neutron maximum mass is between $2.0-2.5 M_{\odot}$ while less than 5 $M_{\odot}$ rarely has been observed. The region star least hole called gap. If indeed its existence confirmed by future that indicates a gap in our understanding which seeks for explanation. In addition, compact objects within should also be supported with help possible new theoretical scenarios....