Effect of radon on SAGE results

A method for estimating the systematic uncertainty associated with radon in the SAGE experiment¹⁾ aimed at observing the solar-neutrino flux is described. For the gallium target used in this experiment, the systematic uncertainty in the measured neutrino-capture rate of 75 SNU²⁾ is below 0.3 SNU.     

Space-time structure of the low-frequency acoustic field in an underwater sound channel

Experimental data are presented on the fine structure of the sound field in an underwater sound channel for low and infralow sound frequencies. The experiments are performed in the Black Sea, on a 600-km-long path, with explosive sound sources. The intensity, space-time, and frequency characteristics of the sound field are analyzed. The geometric dispersion of the first normal wave is experimentally studied. The role of the channel inhomogeneities in the violation of the sound field coherence is determined for different frequency bands. On the basis of the experimental data, the vertical distribution of the critical frequencies of the waveguide is obtained, and the validity limits are established for the wave and ray calculation methods. The applicability of the phase methods for calculating the sound fields in waveguides with dispersion is discussed. The frequency-angular dependence of the effective sound attenuation coefficient in an underwater waveguide is revealed and explained.     

Violation of isotopic invariance in strong interactions and mass spectrum of the 1/2+ baryon octet

The ideas developed by Gell-Mann and Okubo in studying violation of unitary symmetry are used to describe violation of isototic invariance in strong interactions. The present consideration is performed for the example of the mass spectrum of the octet formed by baryons of spin-parity 1/2⁺: only for this family are the widths of its particles much less than the scale of the effects being investigated, their masses being known from experiments to a fairly high precision. The Gell-Mann-Okubo formula is generalized in such a way that relations both for the splitting between the isomultiplets of the octet and for the mass splitting within these isomultiplets follow from the new formula. Moreover, a relation between masses that describes their electromagnetic splitting and which coincides in form with the Coleman-Glashow relation also follows from this formula. The relations obtained for the masses of the baryons belonging to the octet in question are satisfied to a precision not poorer than 3%.     

An Empirical Potential of Interatomic Interaction

A potential of interatomic interaction for simulating complex structural states of solids (grain boundaries and heterogeneous equilibrium states) is put forward. In simulating heterogeneous states of systems, the potential must simultaneously provide for stability conditions for several phases in equilibrium and correct values of a number of macroscopic parameters such as lattice constants, elastic moduli, internal energy, heat capacity, and stability parameters. The existing empirical potentials of interatomic interaction fail to provide agreement of the calculated and experimentally obtained parameters determining the structure of the system and structural transformations due to changes in the external parameters. The potential under discussion is a polynomial representing a solution to the problem of interpolation of functions and their derivatives to the nth order prescribed on a finite system of points (Hermit interpolation problem). The relation for a general solution to the foregoing problem is so complicated that it is virtually inapplicable. A new polynomial is constructed on the basis of the Lagrangian interpolation polynomial. The interpolation of the known interatomic potentials with allowance for the fourth-order derivatives by the polynomial is achieved with high accuracy where three to four interpolation nodes are specified. Local changes can easily be introduced to the polynomial. In doing so, the values of the potential and its derivatives in other regions of space are retained. This allows mechanical stability for stable and metastable phases to be ensured.     

Quasi-hexagonal self-organization of nanoparticles upon the laser-controlled deposition of Ga atoms

A cooperative defect-deformation (DD) mechanism is developed for the nucleation of the quasi-monodisperse ensemble of nanoparticles in the low-temperature deposition of Ga atoms in the presence of laser radiation. A comparison with experiment is carried out, and a good agreement between the theoretical and experimental results has been obtained. In particular, in accordance with the DD model, it has been found that the arrangement of nanoparticles is characterized by a latent hexagonal order, and their shape is quasi-hexagonal. It has been shown that the characteristics of the deposited ensemble of nanoparticles can be controlled with the use of an anisotropic deformation.     

Diffraction of Elastic Waves from a Cylindrical Infinite Cavity with Circular Cross Section Filled by a Liquid

Based on the equations of elasticity theory and hydroacoustics, we calculated the field structures arising when a plane wave is incident on an infinite cylindrical cavity with circular cross section filled by a liquid. The variable pressure component on the cavity axis for longitudinal and shear incident waves is determined.     

Quark masses from regularized integrals of vector current spectral functions

We give estimates of quark masses from a comparison of two methods of regularizing the coefficient of the Schwinger term. The masses of the first radial excited states of ?, ω, and ? would have to be slightly higher than indicated by the new Orsay data for this method to yield real solutions for the masses of theu, d, ands quarks.