[en] For two quantum-mechanical particles in an external field a decomposition is obtained for the integral scattering operator in which all the pole (principal) singularities corresponding to the formation of bound states in independent subsystems (bound states of the first and of the second particle in the field and of the two particles) are separated explicitly. For the unknown functions of this decomposition (the components of the integral scattering operator) a system of integral equations with kernels that have only integrable singularities is obtained. The connection between the elements of the S matrix and the components of the total scattering operator is established. The spectral properties of the total Green's function of the system of two particles in the field are investigated. A method is proposed for generalizing this spectral analysis to the case of a problem of three bodies with arbitrary masses; this method makes it possible to describe the bound states and resonances that arise in the system

[en] The theoretical basis and the experimental methods for identifying relativistic charged particles by measuring ionization energy loss and specific primary ionization are described. Methods for determining more accurately the probable ionization energy loss in multilayer detectors are analyzed. The construction and performance of large proportional and drift chambers used in modern physics experiments are described. The factors that influence the reliability of the identification of the particles in multilayer detectors and determine the intrinsic space and time resolution of these instruments are investigated. The possibilities and conditions of identification of particles by measurement of the specific primary ionization in streamer chambers, by cluster counting in drift chambers, and by the efficiency of a gas-discharge detector and the spark formation time in spark chambers are considered

[en] The analytic structure and geometrical meaning of multipole expansions for systems containing convection and induction currents are illustrated in the framework of classical electrodynamics. The main attention is devoted to the expansion of the transverse electric part of the current, in which the authors have identified a third family of multipole parameters: toroidal moments and their radii. The electromagnetic properties of the simplest toroidal systems are analyzed. The connection between multipole expansions and the methods of invariant parametrizations of relativistic matrix elements of a current operator is emphasized. Some consequences and effects of the existence of these moments are pointed out in the theory of atomic and nuclear transitions. A review is made of the results achieved on the extraction of toroidal moments of nuclear transitions through nuclear conversion penetration parameters, the possibilities of extracting information about toroidal giant resonances, etc. The results are given of the study of anapoles (toroidal dipoles) in the framework of the problem of parity violation by the electroweak interactions in atomic, nuclear, quasinuclear, and quark systems

[en] The present status of theoretical and experimental investigations of excited states of hypernuclei is reviewed. Topics considered are the mechanism of formation of hypernuclei in the (K ^-, π^-) reaction, the influence of the kinematic conditions on the nature of the excitations, and the main features of the cross sections for production of hypernuclei at small momentum transfers. The hyperon--nucleus and residual ΛN interactions are analyzed in a model of particle--hole excitations and in the many-particle shell model. The status of the weak-coupling model is discussed. The properties of the low-lying levels of light Λ hypernuclei are considered. Various approaches to the description of the structure of strangeness analog states are presented. Strong decays of Λ hypernuclei and the associated nucleon--association effects are considered. The problem of summationΛ conversion of summation hypernuclei is discussed

[en] A review of experimental studies made by scientists in the United States, West Germany, and the Laboratory of Nuclear Problems at the Joint Institute for Nuclear Research, Dubna demonstrates the unique possibilities of using muonic atoms for comparative element analysis, in particular in biology and medicine. The method using muonic atoms has a number of advantages over other nuclear-physics methods and has great possibilities for further development and applications in related fields of science and technology

[en] A summary is given of the investigation of a new mode of operation of a wire chamber involving a self-quenching streamer discharge. The history of the question is briefly discussed. The main characteristics of the self-quenching mode and the influence of the composition and pressure of the gas mixture and the geometrical parameters of the chamber on the characteristics are described. The mechanism of a self-quenching streamer discharge is analyzed. Detectors working in this mode are described, and the prospects for its future use are discussed

[en] The main features of the experimental methods of determining the dissipation of relative orbital angular momentum and orientational effects in heavy-ion reactions are briefly described. An estimate of the information that can be extracted from these measurements is given, and qualitative conclusions are drawn about the quasielastic and deep inelastic mechanisms of the studied reactions. The predictions of the various macroscopic and microscopic models are considered, and the theoretical results are compared with one another and with the experimental data. The possible further development of experimental and theoretical investigations is discussed

[en] The geometrical approach to explicitly and completely integrable nonlinear partial differential equations with two independent variables that arise in the theory of relativistic strings is reviewed. The geometry of two-dimensional minimal surfaces in n-dimensional pseudo-Euclidean space is considered. The description of these surfaces by differential forms makes it possible to obtain two series of systems of nonlinear equations whose general solutions can be constructed explicitly. A geometrical method of obtaining new nonlinear equations that admit a Lax representation is presented. These equations describe a relativistic string in de Sitter space--time, a sphere in a three-dimensional unimodular affine space, and a special parametrization on an ordinary sphere in three-dimensional Euclidean space

[en] The basic characteristics of x-ray transition radiation (XTR) are considered; work on the experimental investigation of various types of XTR detector is reviewed. Physics experiments that use such detectors are analyzed. Some recommendations helpful in the development of such detectors are given

[en] First- and second-order Galileo-invariant systems of differential equations which describe the motion of nonrelativistic particles of arbitrary spin are derived. The equations can be derived from a Lagrangian and describe the dipole, quadrupole, and spin-orbit interaction of the particles with an external field; these interactions have traditionally been regarded as purely relativistic effects. The problem of the motion of a nonrelativistic particle of arbitrary spin in a homogeneous magnetic field is solved exactly on the basis of the obtained equations. The generators of all classes of irreducible representations of the Galileo group are found