Peculiarities of null string motion in the gravitational field of a radially expanding or radially collapsing multistring system

Abstract

We have found a solution to the Einstein equations for the case of radial expansion or radial collapse of a multistring system having a layered structure. It has been shown that the influence of the gravitational field of such multistring system can lead to stable oscillations of a test null string in the vicinity of a fixed (stationary) point in space, which can be regarded as a spatially localized particle with a nonzero effective rest mass. In this case, the ability of multistring systems to create such particles can be considered as a possible alternative to the Higgs mechanism. It has also been noted that for a gas of null strings, creation of particles with nonzero effective rest mass is possible at early stages of the Universe evolution, where due to high pressures and a domain structure of such a gas, mutual penetration of null strings belonging to neighboring domains was unavoidable and could emerge in mass. At later stages, due to expansion of the Universe, such an opportunity could be lost.