abstract

Black holes are defined and their properties investigated without use of any global causality restriction. Also the boundary at infinity of space-time is not needed. When the causal conditions are brought in, the equivalence with the usual approach is established.

abstract

The internal symmetry group (dyal symmetry) of relativistic wave equations is considered by means of the Gelfand–Yaglom method. As an example the dyal symmetry of field theory of particles with maximal spin one is investigated.

abstract

The Maxwell solutions to the Yang–Mills SU(2) equations with sources are analyzed from the viewpoint of the bifurcation theory. The necessary and sufficient conditions for the cylindrically symmetric bifurcation are given. An approximate expression for the bifurcating solution is written and its stability is proved.

abstract

It is shown, under weak analyticity assumptions, that high energy bounds on the imaginary and on the real part of a scattering amplitude are correlated. If in a theory the Froissart bound on the imaginary part is substituted by a stronger one, then the bound on the real part is improved as well. Applications of the result to various situations are discussed and the case of the \(\varphi ^4\) theory is explicitly analyzed. The resulting bounds on the real part and on the phase are sensitive to the original deviation from the Froissart bound.

abstract

The helicity-flip contribution in nucleon diffraction dissociation on simple and composite targets is discussed. This contribution is responsible for the observed correlations between the \(t\)-distributions and the mass and the decay angles of the diffractively excited system.

abstract

We show how to incorporate systematically a transparency into thermodynamic models of relativistic ion collisions. The momentum loss of a nucleon per penetration length is evaluated from the free N–N scattering data. Inclusion of transparency in the firestreak model improves agreement with the inclusive data of Gazzaly et al. from 1.8 GeV/nucl lab energy collisions.

abstract

The energy and mass dependent parameters of the local optical model potential for the elastic alpha particle scattering in the energy region of 90–172 MeV on target nuclei from 12 to 208 amu have been proposed and calculated. The calculated cross-sections qualitatively well fit the experimental data in the considered energy and mass region. In order to improve the fits the structure corrections that depend on the number of nucleons outside of the last closed shell could be added to the optical model potential.