abstract

Investigations of exact solutions to the Einstein gravitational field equations are described. A systematic search for solutions with certain symmetries leads to several interesting properties of the gravitational field equations.

abstract

The pp and p\(\overline {\rm p}\) elastic scattering amplitudes are calculated in the dual unitary scheme. It is shown that the crossing symmetry of the pomeron term in the low energy region is restored due to the presence of annihilation channels in the p\(\overline {\rm p}\) scattering. The total annihilation cross section and the \(t\)-dependence of the elastic scattering amplitudes are also discussed.

abstract

Effective potentials of the quartic meson-meson interaction and of the large \(N\ O(N)\) \(\sigma \)-model are examined. In both models the first order radiative corrections restore the symmetry broken in the tree approximation. The potential of the \(O(N)\) \(\sigma \)-model has a minimum which is lower than the one found previously by Coleman, Jackiw and Politzer.

abstract

It is shown that incoherent geometrical composition of probabilities gives a good approximation for the overlap function in collisions of two composite objects. It follows that a detailed understanding of the incident hadron fragmentation is crucial for the correct estimate of the overlap slope in hadron–hadron collisions.

abstract

We assume that the charge distribution in non-diffractive multiparticle production in the Feynman variable \(x\)) is the same as that of valence quarks in the proton. Combining the consequences of this assumption with information from deep inelastic electron–proton, electron–deuteron and neutrino–nucleus data one can separately estimate the parton distribution functions in the proton. The functions obtained in this way (by using charge distribution data including the diffractive component) are, within rather large errors, reminiscent of the usual models of parton distribution functions.

abstract

We interpret the observed departure from Bjorken scaling as a coherent effect of the internal structure of constituent quarks in the nucleon. Then the elastic form-factor of the constituent quark might be determined by precise measurements of this departure, giving crucial information on the nature of quarks. The presented model is orthogonal to that proposed by Chanowitz and Drell.

abstract

Numerical estimates of diffractive dissociation in uncorrelated jet model are performed. The model describes fairly well the absolute magnitude and the general behaviour of diffractive cross-section. It fails badly, however, for the multiplicity distribution. This is mainly due to the fact that only one coherent state has been used as the input.

abstract

It is shown that a “minimal” six quark model based on the Weinberg–Salam theory of unified weak and electromagnetic interactions may be constructed if a small (consistent with experimental uncertainties) deviation from \(e\)–\(\mu \) universality is assumed. This minimal model offers a solution to the difficulties of the standard charm scheme associated with \(R=\sigma (e^++ e^- \to \) hadrons)\(/\sigma (e^++e^-\to \mu ^++\mu ^+)\) and the abundance of \(\mu ^-\mu ^+\) and \(\mu ^-\mu ^+\) pairs in neutrino reactions. It also explains in a natural way the character and smallness of CP violation

abstract

Using certain theorems from the theory of functions a single complex variable, we obtain upper bounds on the derivatives of the pion electromagnetic formfactor at zero momentum-transfer.

abstract

The neutron-deficient \(^{194}\)Bi and \(^{196}\)Bi isotopes were produced in the \(^{181}\)Ta (\(^{20}\)Ne,\(x\)n) and \(^{181}\)Ta (\(^{22}\)Ne,\(x\)n) reactions. The half-lives of \(^{194}\)Bi and \(^{196}\)Bi were found to be \(T_{1/2}=2.0\pm 0.3\) min and \(T_{1/2}=4.6\pm 0.5\) min, respectively. The \(\gamma \)–\(\gamma \) coincidence measurements were carried out. The excited level schemes in \(^{194}\)Pb and \(^{196}\)Pb are presented. The possible spins of the ground states in \(^{194}\)Bi and \(^{196}\)Bi are discussed.

abstract

A method of solving ordinary nonlinear differential equations through a formal series is applied to the approximate calculation of Regge poles. In particular, the nonrelativistic potential theory, Dirac theory and a problem in quasipotential approach are considered.

abstract

The Polya distribution is derived from the minimum information principle, using the measure relative information defined by Kossakowski.