abstract

The general form of the metric of an axially-symmetrical asymptotically de Sitter space-time fulfilling a radiation condition was found. Using the Bondi–Metzner method, the group of asymptotic symmetries of de Sitter space-time was found. The results obtained in this work agree only partially with Penrose’s theory.

abstract

In this paper we study systematically a generalization of the notion of “superenergy tensors” which has been introduced previously in the framework of the General Theory of Relativity on the Einstein–Cartan Theory of Gravitation. It is shown, by means of expansion in the normal coordinate system that the generalization is analytically simple only for the Einstein formulation of conservation laws.

abstract

Approximate Lorentz invariant equations of motion which follow from a gravitational Lagrangian function with higher derivatives are derived. It is shown that in the nonrelativistic limit the equations go over into the Newtonian equations of motion for all values of the additional parameters in the Lagrangian.

abstract

A method is given for obtaining the probability distribution of the number of interacting nucleons of the incident nucleus in collisions of relativistic nuclei. Cross sections and average pion multiplicities in collisions with various total charge of non-interacting fragments of the incident nucleus are used as input data. The method is applied to He+Ta and C+Ta collisions at a momentum of \(p/A\) 4.2 GeV/\(c\). The obtained distributions are compared with calculations using the multiple scattering model.

abstract

Solutions of the Pomeron equation are investigated for large gluon virtual mass \(k_{\bot }^2\). Effects of the running coupling constant for this equation are studied; it is also shown that large \(k_{\bot }^2\) solutions of the Pomeron equation agree with the small \(x\) limit of the DDT equation.

abstract

It is shown that the perturbative calculations in Regge limit in nonabelian gauge theories are in agreement with the hypothesis of the reggeization of vector meson (gluon). The infrared properties of the integral equations for various quantum numbers exchange in the \(t\)-channel are studied in the spontaneously broken theory; the role of the Higgs particles is investigated. Some connections with deep inelastic scattering are also discussed. The integral equation describing the three gluon exchange in a colour singlet state is formulated and its infrared properties are studied. It is argued that it generates a fixed branch point in \(j\)-plane.

abstract

A relativistic solution is given for a quantum-dynamical system which, like \(e^-\alpha \) or \(e^-\pi ^+\), consists of one Dirac particle and one Klein–Gordon particle bound by Coulomb potential. A new fine-structure formula follows displaying explicitly the mass dependence of energy spectrum in the relativistic two-body problem.

abstract

The root mean square radius, the charge form factor, the charge density, the quadrupole moment and the bremsstrahlung weighted cross section for the photodisintegration of \(^6\)Li, are calculated using a polarised cluster model wave function, which is modified to take into account, in its relative motion part, the requirement of a shell model node. A set of parameters, in the modified cluster model wave function, which account for the available experimental data for the afore-said quantities, is determined.

abstract

The \(B\)(E2) values and lifetimes of the first 2\(^+\) states of the even palladium isotopes and the 279.9, 319.3, 442.1, 565.7 and 781.7 keV states of \(^{105}\)Pd have been measured from the Coulomb excitation with 3.2 MeV protons by observing the de-excitedgamma-rays with a high resolution Ge(Li) detector. The 319.3, 561.7 and 78L7 keV states have been observed for the first time in the Coulomb excitation with low-energy protons. The change in collective behaviour of the first 2\(^+\) states with the change in neutron number has been noticed in even palladium nuclei. The properties of the excited states of \(^{105}\)Pd have been discussed in the light of core particle coupling models.

abstract

The new isotope \(^{146}\)Dy \(T_{1/2} = 32\pm 5\)s has been identified on the IRIS on-line mass-separator facility coupled to the 1 GeV proton beam from the synchrocyclotron. The identification is based on the analysis of the X-ray and \(\gamma \)-ray spectra.