acta physica slovaca

Acta Physica Slovaca 49(1999)
  • I. Radinschi
    The energy of a dyonic dilaton black hole
    Acta Physica Slovaca 49, 789 (1999)

    Abstract: We calculate the energy distribution of a dyonic dilaton black hole by using the Tolman's energy-momentum pseudotensor. All the calculations are performed with approximation in quasi-Cartesian coordinates. The energy distribution of the dyonic dilaton black hole depends on the mass M, the electric charge Qe, the magnetic charge Qm and asymptotic value of the dilaton . We get the same result as obtained by Y-Ching Yang, Ching-Tzung Yeh, Rue-Ron Hsu and Chin-Rong Lee by using the Einstein's prescription.

  • Z. Stuchlík, S. Hledík
    Embedding diagrams of the optical geometry of Kerr backgrounds
    Acta Physica Slovaca 49, 795 (1999)

    Abstract: Embedding diagrams of the equatorial plane of Kerr black holes and naked singularities are constructed for the optical reference geometry related to the family of locally non-rotating observers. It is shown that turning points of the diagrams correspond to radii at which centrifugal force related to the optical geometry vanish. The corotating photon circular orbits above the outer horizon enter the embedding diagrams only for black holes with specific angular momentum a2< 0.505658861, while the counterrotating photon circular orbits enter the diagrams for all black holes and naked singularities.

  • C. Wolf
    Thermodynamic equilibrium of pyrgons and radiation
    Acta Physica Slovaca 49, 805 (1999)

    Abstract: By considering the pyrgons generated by the Planck scale excitations of massive scalar field to be equilibrium with radiation we calculate the favored equilibrium condition of pyrgons and radiation.

  • Ch. Cronström
    Canonical structure of Yang-Mills theory
    Acta Physica Slovaca 49, 811 (1999)

    Abstract: I consider the problem of defining canonical coordinates and momenta in pure Yang-Mills theory, under the condition that Gauss' law is identically satisifed. This involves among other things particular boundary conditions for certain dependent variables. These boundary conditions are not postulated a priori, but arise as consistency conditions related to the equations of motion. It is shown that the theory indeed has a canonical structure, provided one uses a special gauge condition, which is a natural generalisation to Yang-Mills theory of the Coulomb gauge condition in electrodynamics. The canonical variables and Hamiltonian are explicitly constructed. Quantisation of the theory is briefly discussed.

  • G. K. Yeghiyan
    Upper bound on the lightest Higgs mass in supersymmetric theories
    Acta Physica Slovaca 49, 823 (1999)

    Abstract: The problem of the lightest Higgs boson mass in the next-to-minimal supersymmetric standard model (NMSSM) is investigated. Assuming the validity of the perturbation theory up to unification scales and using the recent experimental results for the top quark mass, the restrictions on the NMSSM coupling constants are obtained. These restrictions are used to make the predictions for the lightest Higgs mass, which are compared to those of the minimal supersymmetric standard model (MSSM).

  • T.S. Biró, P. Lévai, J. Zimányi, Ch. T. Traxler
    Hadronization and strangeness production in heavy-ion collisions
    Acta Physica Slovaca 49, 835 (1999)

    Abstract: The hadronization process of a quark matter possibly formed in relativistic heavy ion experiments at CERN SPS and RHIC is addressed in the framework of a non-equilibrium approach using hadron formation rates for effectively massive quarks and gluons. After a brief review of the relevant thermodynamical concepts consequences of string formation on the hadron composition are investigated in the transchemical quark fusion model and in a molecular dynamical simulation of the semiclassical chromodielectric model.

  • M. Martinis, V. Mikuta-Martinis, J. Crnugelj
    Disoriented chiral condensates and anomalous production of pions
    Acta Physica Slovaca 49, 875 (1999)

    Abstract: The leading-particle effect and the factorization property of the scattering amplitude in the impact parameter space are used to study semiclassical production of pions in the central region. The mechanism is related to the isospin-uniform solution of the nonlinear -model coupled to quark degrees of freedom. The multipion exchange potential between two quarks is derived. It is shown that the soft chiral pion bremsstralung also leads to anomalously large fluctuations in the ratio of neutral to charged pion. We show that only direct production of pions in the form of an isoscalar coherent pulse without isovector pairs can lead to large neutral-charged fluctuations.

  • M. Morhác, V. Matousek
    Matched fast Haar wavelet transform and its application for coincidence nuclear spectra compression
    Acta Physica Slovaca 49, 889 (1999)

    Abstract: The paper describes a new fast matched Haar wavelet transform aimed for the use in the nuclear spectra compression. The proposed transform is compared with other classical transforms. The results obtained prove in favour of the matched Haar wavelet transform.

  • R. Varga, P. Vojtaník, J. Kovác, P. Agudo, M. Vázquez, A. Lovas
    Influence of Cr on magnetic and structural properties of amorphous Fe80-xCrxSi6B14 (x=0-14) alloys
    Acta Physica Slovaca 49, 901 (1999)

    Abstract: The influence of Cr on the magnetic as well as on the structural properties has been investigated. Thermomagnetic analysis is made in order to find the influence of Cr on the Curie temperature and the DSC measurements are used to study the crystallization behaviour. It was found that Cr decreases the Curie themperature and linearizes the temperature dependence of the susceptibility that results in the decrease of relaxation. From the DSC measurements, two crystallization peaks were found for lower Cr concentrations. Increasing the Cr concentration reduces crystallization into one crystallization step. The crystallization temperature increases when the Cr concentration increases.

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