acta physica slovaca

Abstract: The paper presents general protocols for quantum teleportation between many parties. It is shown how N parties can teleport unknown quantum states to M other parties with the use of N+M qudits in the maximally entangled state.

Abstract: By using the unitary and analytic model of nucleon electromagnetic structure the problem of inconsistency of proton electric form factor data in space-like region (obtained from e- p -> e- p process by the Rosenbluth technique) with recent Jefferson Lab data on ratio G_{Ep}(t)/G_{Mp}(t) (measured in precise polarization vec{e}- p -> \to e- vec{p} experiment) has been solved in favour of the latter. However, the new data strongly require an existence of a zero, i.e. a diffraction minimum in G_{Ep}(t) around t=-Q^2=-15 GeV^2, which may change our conception about the charge distribution inside of the proton.

Abstract: Using the S-matrix formalism and Feynman's diagram technique, the gravitational scattering of the zero-rest-mass and massive 1/2-spin and 3/2-spin particles on the ''far field'' of a Kerr black-hole is studied. The calculations have been made in the first order of the Born approximation, but taking into account the contribution brought by the covariant derivative, according to the principle of minimal coupling in Quantum Gravity.

Abstract: The concept of z-scaling that reflects the general features of internal particle substructure, constituent interaction, and mechanism of particle formation at high-p_T is reviewed. The experimental data on inclusive cross sections obtained at the U70, ISR, SpS, RHIC and Tevatron are analyzed. The properties of z-presentation of data such as the energy independence, power law, and A-dependence are discussed. The properties of z-scaling are argued to be connected with the fundamental symmetries such as self-similarity, locality and fractality. The use of z-scaling to search for new physics phenomena in collisions of hadrons and nuclei is suggested. RHIC data used in our new analysis confirm z-scaling in pp collisions. High-p_T particle spectra at LHC energies are predicted. Violation of z-scaling characterized by the change of the anomalous fractal dimension is considered as a new and complementary signature of new physics phenomena.

Abstract: The tensor analyzing power Ayy of the 9Be(d,p)X reaction at an initial deuteron momentum of 5 GeV/c and a proton detection angle of 180 mr has been measured at the JINR Synchrophasotron. The preliminary data obtained are compared with the relativistic calculations made within the framework of the light-front dynamics. With Karmanov's relativistic deuteron wave function we have managed to explain the new data without invoking degrees of freedom additional to nucleon ones.

Abstract: We give an overview of results and prospects of nuclear clustering studies on the grounds of the observations of interactions of light stable and radioactive nuclei with an initial energy above 1 AGeV in nuclear emulsions. Thank to the best spatial resolution and the full solid angle acceptance provided by nuclear emulsions, such an approach allows one to obtain unique and evident observations reflecting cluster-like features in light nuclear structures. New results on dissociation of 7Be in very peripheral interactions with emulsion nuclei are presented. The importance of this research for the physics of few body nuclear systems and the related problems of nucleosynthesis is noted. The paper is illustrated with characteristic images obtained by means of a microscope equipped with a CCD camera. The discussed explorations are provided with the beams of the Synchrophasotron and Nuclotron of JINR, Dubna. Future investigations are suggested to be carried out in relativistic beams of He, Be, B, C, and N isotopes.

Abstract: The high-momentum structure of the ${}^3$He, ${}^3$H and deuteron in the experiment with polarized deuteron beam performed at Ed=270 MeV at RIKEN, Japan in December 2000, was investigated. For this purpose the angular dependence of the tensor and vector analyzing powers were measured for the reactions d + d -> 3H + p and d + d -> 3He + n. In this report the results on the tensor Ayy and vector Ay analyzing powers are presented in the full angular range. The energy dependence of the tensor analyzing power T_20 at a zero degree is also shown. First results on the Ay and Ayy in the d + d -> p + X reaction near threshold are obtained.

Abstract: The HADES spectrometer installed at GSI Darmstadt is devoted to the study of the production of di-lepton pairs from vector meson decays in relativistic nucleus-nucleus collisions, as well as proton- and pion-induced reactions. Extraction of rare lepton pairs in high hadron multiplicity events requires an efficient particle identification (PID). In HADES charged particles momentum is measured by a tracking system surrounding the toroidal super conducting magnet, and velocity and energy loss is provided by a TOF detector. Leptons are identified by a Rich as well as a Shower detector. The particle identification method is using full experimental information from all subdetectors. To demonstrate the method performance, single particle spectra of charged hadrons and leptons from C+C at 2 AGeV will be presented and compared with results of corresponding simulations. The proton and pion yields an m_T and rapidity distributions will be compared with existing data. Very preliminary results of lepton analysis will be shown as well.

Abstract: This paper describes graphical models of visualization of 2-, 3-, 4-dimensional scalar data used in nuclear data acquisition, processing and visualization system developed at the Institute of Physics, Slovak Academy of Sciences. It focuses on presentation of nuclear spectra (histograms). However it can be successfully applied for visualization of arrays of other data types. In the paper we present conventional as well as new developed surface and volume rendering visualization techniques used.

Abstract: The paper reports on experimental results and numerical studies of a possibility of the application of ion beams emitted from plasma focus discharges for target activation. The complete data obtained from the activation of a carbon target and also numerical prognoses for the 13N isotope production are presented. Deuterons emitted from a plasma focus facility bombarded a carbon target and they produced positron-emitting isotopes. Gamma quanta with energy 511 keV were obtained from annihilation of positron-electron pairs. Gamma spectrometry has been used to measure the induced activity. The activity of isotopes was determined using a multichannel analyzer and a high purity germanium detector. The activity of the 13N isotope was of the order of tens of thousands Bq and was compared with that obtained by numerical estimation.

Abstract: A new method is described to deposit synthetic opal films by using the Langmuir-Blodgett (LB) technique. We show that, using a NIMA two compartment trough, good quality films can be formed if the substrate is maintained in a horizontal position during the drying period between dips. The first layers to be deposited consists of a number of highly ordered domains which make good contact with one another but which have differing crystal orientation. With the deposition of further layers the domain structure gradually disappears but these further layers have a good degree of order with regions which are as regular in structure as the domains.

Abstract: Thin films of ZnSe:Al were deposited on glass substrates by laser assisted evaporation. Parameters such as crystal structure, optical and electrical properties of the films have been investigated. X-ray diffraction shows that prepared films are polycrystalline with preferred (111) orientation and having a zinc blend cubic structure. The lattice constant has been evaluated for ZnSe, the value was found to be 0.56 nm, and the value does not show any appreciable change with the addition of aluminium. From optical measurement, it was found that optical band gap, Eg, decreases on adding Al. The value changes from 2.62 eV (for ZnSe) to 1.85 eV with 3.0 wt % of Al in the film. Hall effect measurements showed that the films are all n-type and the carrier concentration increases with the increase of Al concentration in the film. DC electrical conductivity may be thermally activated with negligible activation energy only when the Al concentration is lower than 3 wt % at temperature up to 200° C, and the transport process may involve hopping of electrons in the localized states near the conduction band edge. However, at higher concentration of Al the process is dominated by usual transition of electrons to the mobility edge. Addition of Al up to 3 wt % does not only increase the electrical conductivity by a factor of 10^2 but also the carrier concentration by a factor of 10^3 which may bring about electron degeneracy at room temperature by dislodging the Fermi level.