J. Zmeskal
A5103562461- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Atomic and Molecular Physics
- Muon and positron interactions and applications
- Atomic and Subatomic Physics Research
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Nuclear physics research studies
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Radioactive Decay and Measurement Techniques
- Radiation Detection and Scintillator Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Cold Atom Physics and Bose-Einstein Condensates
- High-pressure geophysics and materials
- Particle accelerators and beam dynamics
- Quantum Mechanics and Applications
- Advanced Chemical Physics Studies
- Ionosphere and magnetosphere dynamics
- Neutrino Physics Research
- Noncommutative and Quantum Gravity Theories
- Cold Fusion and Nuclear Reactions
- Superconducting Materials and Applications
- Magnetic confinement fusion research
Stefan Meyer Institute for Subatomic Physics
2015-2024
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2011-2024
Istituto Nazionale di Fisica Nucleare
2006-2024
Austrian Academy of Sciences
2013-2022
Tokyo Institute of Technology
2022
Czech Academy of Sciences, Institute of Physics
2022
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2011-2022
Enrico Fermi Center for Study and Research
2019-2022
Technical University of Munich
1989-2022
Excellence Cluster Universe
2021-2022
The $\bar{K}N$ system at threshold is a sensitive testing ground for low energy QCD, especially the explicit chiral symmetry breaking. Therefore, we have measured $K$-series x rays of kaonic hydrogen atoms DA$\Phi$NE electron-positron collider Laboratori Nazionali di Frascati, and determined most precise values strong-interaction energy-level shift width $1s$ atomic state. As x-ray detectors, used large-area silicon drift detectors having excellent timing resolution, which were developed...
The DEAR (DAPhiNE exotic atom research) experiment measured the energy of x rays emitted in transitions to ground state kaonic hydrogen. values for shift epsilon and width Gamma 1s due K(-)p strong interaction are epsilon(1s)=-193 +/- 37 (stat) 6 (syst) eV Gamma(1s)=249 111 30 eV, most precise yet obtained. pattern hydrogen K-series lines, K(alpha), K(beta), K(gamma), was disentangled first time.
Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart—hydrogen—is one of most precisely investigated and best understood systems in physics research. High-resolution comparisons both provide sensitive tests CPT symmetry, which fundamental symmetry Standard Model elementary particle physics. Any measured difference would point violation thus new Here we report development antihydrogen source using cusp trap for in-flight spectroscopy. A total 80 atoms are...
Muon-catalyzed deuterium-tritium fusion was investigated within a wide range of mixtures in liquid and gas (23--35 K) by detection neutrons. Our improved analysis includes hyperfine effects allows clear separation intrinsic dt sticking ${\ensuremath{\omega}}_{s}$ from kinetic effects. Strongly density-dependent cycle rates with values up to 1.45\ifmmode\times\else\texttimes\fi{}${10}^{8}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$, yields 113 fusions per muon,...
Abstract The precise measurement of forces is one way to obtain deep insight into the fundamental interactions present in nature. In context neutral antimatter, gravitational interaction high interest, potentially revealing new that violate weak equivalence principle. Here we report on a successful extension tool from atom optics—the moiré deflectometer—for acceleration slow antiprotons. setup consists two identical transmission gratings and spatially resolving emulsion detector for...
Kaonic atoms are exotic atomic systems where an electron is replaced by a negatively charged kaon which also experiences the strong interaction with nucleus. Precision spectroscopy of kaonic represents excellent tool to study particles strangeness. This work reviews progress and prospects in modern era atom experiments, discusses constraints on low-energy theories strangeness sector.
We demonstrate the laser excitation of $n=3$ state positronium (Ps) in vacuum. A combination a specially designed pulsed slow positron beam and high-efficiency converter target was used to produce Ps. Its annihilation recorded by single-shot lifetime spectroscopy. Pulsed level at wavelength $\ensuremath{\lambda}\ensuremath{\approx}205$ nm monitored via Ps photoionization induced second intense pulse $\ensuremath{\lambda}=1064$ nm. About 15% overall emitted into vacuum excited photoionized....
We report the measurement of K− absorption processes in Σ0p final state and first exclusive two nucleon (2NA) with KLOE detector. The 2NA process without further interactions is found to be 9% sum all other contributing processes, including on three more nucleons or followed by residual nucleons. also determine possible contribution ppK− bound state. yield ppK−/Kstop− (0.044±0.009stat−0.005+0.004syst)⋅10−2 but its statistical significance based an F-test only 1σ.
We observed a distinct peak in the Λp invariant mass spectrum of He3(K−,Λp)n, well below mK+2mp, i.e., threshold K− to be bound two protons. By selecting relatively large momentum-transfer region q=350∼650 MeV/c, one can kinematically separate from quasi-free process, K‾N→K‾N followed by non-resonant absorption spectator-nucleons K‾NN→ΛN. found that simplest fit gives us Breit–Wigner pole position at BKpp=47±3(stat.)−6+3(sys.) MeV having width ΓKpp=115±7(stat.)−20+10(sys.) MeV, and S-wave...
We have measured the Balmer-series x-rays of kaonic $^4$He atoms using novel large-area silicon drift x-ray detectors in order to study low-energy $\bar{K}$-nucleus strong interaction. The energy $3d \to 2p$ transition was determined be 6467 $\pm$ 3 (stat) 2 (syst) eV. resulting strong-interaction energy-level shift is agreement with theoretical calculations, thus eliminating a long-standing discrepancy between theory and experiment.
A model where a Dirac fermion is coupled to background dilaton field considered study s-wave scattering of by back ground black hole. It found that an uncomfortable situation towards information loss scenario arises when one loop correction gets involved during bosonization.
The possible existence of deeply bound $\bar K$-nucleus states (kaonic nuclei) has been widely discussed as a consequence the strongly attractive K N$ interaction in I = 0 channels. For simplest kaonic nucleus, KNN$, we observed significant peak structure that can be interpreted ``$K^-pp$'' state using $^3$He$(K^-,N)$ reactions at J-PARC. To further understand nuclei, have proposed and prepared an experiment to precisely measure NNN$ system $^4$He$(K^-,N)$ first step towards comprehensive...
The SIDDHARTA-2 collaboration is performing research in the field of kaonic atoms spectroscopy. In this work, following an introduction on and their importance for development low-energy strong interaction theories, first result experiment (kaonic helium) presented. This measurement was promising view main goal experiment, i.e. deuterium transitions to 1s level, important model kaon-nucleon interaction. last part paper future plans measure new key quantities with beyond stat-of-the-art...
High rates for mesomolecular processes were found in a study of neutron spectra from muon-catalyzed $\mathrm{dt}$ fusion low-density D/T mixtures. An interpretation is given terms reaction-kinetics model which includes hyperfine effects. The components the $d\ensuremath{\mu}t$ formation rates, first separated this experiment, are large 30 to 300 K. unexpected temperature dependence transition rate between $\ensuremath{\mu}t$ states found.
We describe a system designed to re-bunch positron pulses delivered by an accumulator supplied source and Surko-trap. Positron from the are magnetically guided in 0.085 T field injected into region free of magnetic fields through μ-metal terminator. Here positrons temporally compressed, electrostatically accelerated towards porous silicon target for production emission positronium vacuum. Positrons focused spot less than 4 mm FWTM bunches ∼8 ns FWHM. Emission vacuum is shown single shot...
The goal of the ASACUSA-CUSP collaboration at Antiproton Decelerator CERN is to measure ground-state hyperfine splitting antihydrogen using an atomic spectroscopy beamline. A milestone was achieved in 2012 through detection 80 atoms 2.7 m away from their production region. This first observation ‘cold’ a magnetic field free In parallel progress on production, beamline tested with source hydrogen. led measurement relative precision 2.7×10 −9 which constitutes most precise hydrogen beam....
Abstract The hadronic width of the ground state pionic hydrogen has been redetermined by X-ray spectroscopy to be $$\varGamma ^{\pi \mathrm {H}}_{1s}=(856\,\pm \,16_\mathrm{stat}\,\pm \,22_\mathrm{sys})$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msubsup> <mml:mi>Γ</mml:mi> <mml:mn>1</mml:mn> <mml:mi>s</mml:mi> </mml:mrow> <mml:mi>π</mml:mi> <mml:mi>H</mml:mi> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mo>(</mml:mo> <mml:mn>856</mml:mn> <mml:mspace />...
A large area silicon drift detectors (SDDs) system and its readout electronics have been developed by the SIDDHARTA-2 Collaboration, aiming to perform high-precision light kaonic atoms x-ray spectroscopy for investigation of strong interaction in low-energy QCD regime. To these measurements, a linear energy response good resolution are mandatory requirements system, be preserved along whole DAQ (analog digital) chain; such task is made even harder experimental environment particles...
Abstract The current work presents the optimization of large area silicon drift detectors developed by SIDDHARTA-2 collaboration for high precision x-ray measurements light exotic atom transitions. Two different radiation sources were employed in study: an tube, investigating energy resolution and charge collection efficiency device range 4000 eV–13 000 eV, a β − 90 Sr radioactive source measuring timing response, thus qualifying parameters inside semiconductor. study reports spectroscopic...