Volume 29, Issue 1, January 1998
29(1998); http://dx.doi.org/10.1134/1.953058View Description Hide Description
This review of the relativistic theory of gravity describes the developments in this theory during the last ten years, for example, the necessity of introducing a graviton mass and the improved statement of the basic propositions of the theory, including the philosophical aspects of choosing a particular spacetime geometry to describe physical phenomena dictated by the universal properties of the motion of matter and the fundamental conservation laws. It is shown that this theory leads to a uniquely defined Lagrangian density and to equations for the gravitational field. Some physical consequences of the theory are discussed.
29(1998); http://dx.doi.org/10.1134/1.953059View Description Hide Description
The derivation of effective mesonLagrangians in higher orders of the chiral expansion from bosonization of the four-quark interaction of the extended Nambu–Jona-Lasinio (NJL) model, treated as a local approximation of low-energy QCD, is reviewed. The calculated heat-kernel coefficients for the quark determinant of the bosonized NJL model through seventh order are presented in a systematic way. The results are used to fix the structure coefficients of the effective chiral Lagrangians in orders and of the momentum expansion. Various aspects of the use of bosonized Lagrangians to describe low-energy meson processes are discussed: the reduction of vector, axial-vector, and scalar resonances, regularization of graphs with meson loops, and the dependence of the phenomenological structure coefficients on the renormalization scheme and regularization parameters. Questions related to the physical justification of the NJL model as a low-energy limit of QCD are also discussed. Nonlocal corrections to the structure coefficients of bosonized Lagrangians are studied in this context.
29(1998); http://dx.doi.org/10.1134/1.953060View Description Hide Description
The existing methods of constructing an explicitly resonance, unitary matrix are reviewed. These methods can be used for describing groups of resonances with identical quantum numbers in the case where they overlap, when The relation between these methods is studied in detail. The description of excited states by means of the Breit–Wigner formulas is used most often in many problems of resonance physics and nuclear physics, and in this review we focus on the construction of a unitary, -invariant, multichannel, multiresonance matrix of the Breit–Wigner type. As a real application of these methods we study the excitation spectrum of vector ρ and ω mesons. The possibility of interpreting these as quark–antiquark excited states is discussed.
29(1998); http://dx.doi.org/10.1134/1.953061View Description Hide Description
A review of the problem of whether the violation of the OZI rule in nucleon–antinucleon annihilation at rest can be explained in the framework of conventional mechanisms is given in detail. While the vector-dominance model and the rescattering model qualitatively describe the OZI-rule violation in the reactions and for the annihilation from the state of the protonium atom, the latter model cannot explain the fact that the annihilation into from the state is not seen and the OZI rule in the reaction is not satisfied. We also discuss what information about the OZI-rule violation can be extracted from the reaction and decays of the meson.