J. Steṕaniak
A5061293781- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Quantum, superfluid, helium dynamics
- Particle Detector Development and Performance
- Astrophysics and Cosmic Phenomena
- Particle accelerators and beam dynamics
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Magnetic confinement fusion research
- Radiation Detection and Scintillator Technologies
- Scientific Research and Discoveries
- Advanced NMR Techniques and Applications
- Cold Fusion and Nuclear Reactions
- Nuclear reactor physics and engineering
- Stochastic processes and statistical mechanics
- Computational Physics and Python Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Physics of Superconductivity and Magnetism
- Scientific Computing and Data Management
National Centre for Nuclear Research
2016-2025
Uppsala University
1996-2020
Jagiellonian University
2012-2019
Forschungszentrum Jülich
2014-2016
Heinrich Heine University Düsseldorf
2014-2016
Johannes Gutenberg University Mainz
2013-2016
National Research Tomsk State University
2016
High Energy Accelerator Research Organization
2013-2016
University of Delhi
2014
University of Bern
2014
We report on an exclusive and kinematically complete high-statistics measurement of the basic double-pionic fusion reaction pn→dπ(0)π(0) over full energy region ABC effect, a pronounced low-mass enhancement in ππ-invariant mass spectrum. The measurements, which cover also transition to conventional t-channel ΔΔ process, were performed with upgraded WASA detector setup at COSY. data reveal Abashian-Booth-Crowe effect be uniquely correlated Lorentzian dependence integral cross section....
The ABC effect-a puzzling low-mass enhancement in the pipi invariant mass spectrum, first observed by Abashian, Booth, and Crowe-is well known from inclusive measurements of two-pion production nuclear fusion reactions. Here we report on exclusive kinematically complete most basic double-pionic reaction pn-->dpi;{0}pi;{0} at beam energies 1.03 1.35 GeV. measurements, which have been carried out CELSIUS-WASA, reveal effect to be a (pipi)_{I=L=0} channel phenomenon associated with both...
Exclusive and kinematically complete high-statistics measurements of quasifree polarized $\stackrel{\ensuremath{\rightarrow}}{n}p$ scattering have been performed in the energy region narrow resonancelike structure ${d}^{*}$ with $I({J}^{P})=0({3}^{+})$, $M\ensuremath{\approx}2380\text{ }\text{ }\mathrm{MeV}$, $\mathrm{\ensuremath{\Gamma}}\ensuremath{\approx}70\text{ }\mathrm{MeV}$ observed recently double-pionic fusion channels...
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...
Exclusive measurements of the quasifree $pn\ensuremath{\rightarrow}pp{\ensuremath{\pi}}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$ reaction have been performed by means $pd$ collisions at ${T}_{p}$ $=$ 1.2 GeV using wide angle shower apparatus (WASA) detector setup cooler synchrotron COSY (Institut f\"ur Kernphysik, J\"ulich). Total and differential cross sections obtained covering energy region $\sqrt{s}$ (2.35--2.46) GeV, which includes ABC effect its associated resonance structure. No...
We report an early result from the ICARUS experiment on search for a ν μ →ν e signal due to LSND anomaly. The was performed with T600 detector located at Gran Sasso Laboratory, receiving CNGS neutrinos CERN average energy of about 20 GeV, after flight path ∼730 km. anomaly would manifest as excess events, characterized by fast oscillation averaging approximately $\sin^{2}(1.27\Delta m^{2}_{\mathrm{new}}L/E_{\nu})\approx 1/2$ probability $P_{\nu_{\mu}\rightarrow \nu_{e}} = 1/2...
New data on quasifree polarized neutron-proton scattering in the region of recently observed ${d}^{*}$ resonance structure are obtained by exclusive and kinematically complete high-statistics measurements with WASA at COSY. This paper details determination beam polarization, checks character process, all ${A}_{y}$ angular distributions new partial-wave analysis, which includes producing a pole ${}^{3}{D}_{3}\ensuremath{-}{}^{3}{G}_{3}$ coupled partial waves...
Exclusive measurements of the quasi-free $np \to np\pi^0\pi^0$ reaction have been performed by means $dp$ collisions at $T_d$ = 2.27 GeV using WASA detector setup COSY. Total and differential cross sections obtained covering energy region $\sqrt s$ (2.35 - 2.46) GeV, which includes ABC effect its associated $d^*(2380)$ resonance. Adding $d^*$ resonance amplitude to that for conventional processes leads a reasonable description data. The observed in total section is agreement with predictions...
The CERN-SPS accelerator has been briefly operated in a new, lower intensity neutrino mode with ~10^12 p.o.t. /pulse and beam structure made of four LHC-like extractions, each narrow width 3 ns, separated by 524 ns. This very tightly bunched represents substantial progress respect to the ordinary operation CNGS beam, since it allows accurate time-of-flight measurement neutrinos from CERN LNGS on an event-to-event basis. ICARUS T600 detector collected 7 beam-associated events, consistent...
An exclusive measurement of the excitation function for dd->3Heppi- reaction was performed at Cooler Synchrotron COSY-Juelich with WASA-at-COSY detection system. The data were taken during a slow acceleration beam from 2.185 GeV/c to 2.400 crossing kinematic threshold eta meson production in dd->4He-eta 2.336 GeV/c. corresponding excess energy respect 4He-eta system varied -51.4MeV 22MeV. integrated luminosity experiment determined using dd->3Hen reaction. shape examined. No signal bound...
A bstract During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks a total of ~1.8 × 10 17 p.o.t., with proton made bunches, few ns wide and separated by 100 ns. This structure allows very accurate time flight measurement neutrinos from CERN to LNGS on an event-by-event basis. Both ICARUS-T600 PMT-DAQ CERN-LNGS timing synchronization have substantially improved this campaign, taking advantage additional independent GPS receivers, both at as well deployment “White Rabbit”...
The quasifree $p+n\ensuremath{\rightarrow}d+\ensuremath{\eta}$ reaction cross section has been measured at the threshold using 1295 MeV protons in CELSIUS storage ring and an internal cluster-jet deuterium target. kinematics is chosen such that target proton can be assumed to a spectator. Fermi momentum of neutron used extract energy dependence by reconstructing on event-by-event basis. data cover excess energies from 10 center mass final $d\ensuremath{\eta}$ system. Approaching enhanced...
The quasifree p+n→d+η reaction cross section has been measured in the near-threshold region using deuterium from an internal cluster-jet target and 1350 MeV protons CELSIUS storage ring of Svedberg Laboratory, Uppsala. energy dependence is extracted by exploiting Fermi momentum neutron reconstructing kinematics on event-by-event basis. data cover center mass excess energies 16 to 113 MeV.Received 14 April 1997DOI:https://doi.org/10.1103/PhysRevLett.79.2642©1997 American Physical Society