arXiv subjects

S. I. Kruglov

Publications and source records attributed to S. I. Kruglov.

117 records · Page 7Linked to original sources

arXiv2001

Charge Radii and Magnetic Polarizabilities of the Rho and K* Mesons in QCD String Theory

The effective action for light mesons in the external uniform static electromagnetic fields was obtained on the basis of QCD string theory. We imply that in the presence of light quarks the area law of the Wilson loop integral is valid. The approximation of the Nambu-Goto straight-line string is used to simplify the problem. The Coulomb-like short-range contribution which goes from one-gluon exchange is also neglected. We do not take into account spin-orbital and spin-spin interactions of quarks and observe the $ρ$ and $K^*$ mesons. The wave function of the meson ground state is the Airy function. Using the virial theorem we estimate the mean charge radii of mesons in terms of the string tension and the Airy function zero. On the basis of the perturbative theory, in the small external magnetic field we find the diamagnetic polarizabilities of $ρ$ and $K^*$ mesons: $β_ρ=-0.8\times 10^{-4} {fm}^3$, $β_{K^*}=-0.57\times 10^{-4} {fm}^3$

hep-ph↗

arXiv2001

Effective Actions, Radii and Electromagnetic Polarizabilities of Hadrons in QCD String Theory

A nonperturbative approach to QCD describing confinement and chiral symmetry breaking is discussed. It is based on the path integral representation of Green's function of quarks and leads to the QCD string theory. The effective actions for mesons and baryons in the external uniform static electromagnetic fields are obtained. The area law of the Wilson loop integral, the approximation of the Nambu-Goto straight-line string, and the asymmetric quark-diquark structure of nucleons are used to simplify the problem. The spin-orbit and spin-spin interactions of quarks are treated as a perturbation. Using the virial theorem we estimate the mean radii of hadrons in terms of the string tension and the Airy function zeros. On the basis of the perturbation theory in small external electromagnetic fields we derive the electromagnetic polarizabilities of nucleons. The electric and diamagnetic polarizabilities of a proton are $\barα_p= 10\times 10^{-4} fm^3$, $β_p^{dia}=-8\times 10^{-4} fm^3$ and for a neutron we find $\barα_n=4.2\times 10^{-4} fm^3 $, $β_n^{dia}= -5.4\times 10^{-4} fm^3$. Using the $Δ$ contribution to the paramagnetic polarizability of the nucleons, reasonable values of the magnetic polarizabilities $\barβ_p=(5\pm 3)\times 10^{-4} fm^3$, $\barβ_n=(7.6\pm 3)\times 10^{-4} fm^3$ are estimated.

hep-ph↗

arXiv2001

Generalized Maxwell Equations and Their Solutions

The generalized Maxwell equations are considered which include an additional gradient term. Such equations describe massless particles possessing spins one and zero. We find and investigate the matrix formulation of the first order of equations under consideration. All the linearly independent solutions of the equations for a free particle are obtained in terms of the projection matrix-dyads (density matrices).

math-ph↗

arXiv2001

Internal Symmetry Group and Density Matrix of Fields with Spins 0, 1

The internal symmetry group U(3,1) of the neutral vector fields with two spins 0 and 1 is investigated. Massless fields correspond to the generalized Maxwell equations with the gradient term. The symmetry transformations in the coordinate space are integro-differential transformations. Using the method of the Hamiltonian formalism the conservation tensors are found, and the quantized theory is studied. The necessity to introduce an indefinite metric is shown. The internal symmetry group U(3,1) being considered, after the transition to electrodynamics, reduces to the U(2) group. It is shown that the group of dual transformations is the subgroup of the group under consideration. All the linearly independent solutions of the equation for a free particle obtained in terms of the projection matrix-dyads.

quant-ph↗

arXiv2001

Pair Production and Vacuum Polarization of Arbitrary Spin Particles with EDM and AMM

The exact solutions of the wave equation for arbitrary spin particles with electric dipole and magnetic moments in the constant and uniform electromagnetic field were found. The differential probability of pair production of particles by an external electromagnetic field has been calculated on the basis of the exact solutions. We have also estimated the imaginary part of the constant and uniform electromagnetic field. The nonlinear corrections to the Maxwell Lagrangian have been calculated taking into account the vacuum polarization of arbitrary spin particles. The role of electric dipole and magnetic moments of arbitrary spin particles in instability of the vacuum is discussed.

hep-th↗

arXiv2001

Pair Production and Vacuum Polarization of Vector Particles with Electric Dipole Moments and Anomalous Magnetic Moments

The matrix, 8-component Dirac-like form of P-odd equations for boson fields of spins 1 and 0 are obtained and the GL(2,c) symmetry group of equations is derived. We found exact solutions of the field equation for vector particles with arbitrary electric and magnetic moments in external constant and uniform electromagnetic fields. The differential probability of pair production of vector particles with the EDM and AMM by an external constant and uniform electromagnetic field has been found using the exact solutions. We have calculated the imaginary and real parts of the electromagnetic field Lagrangian that takes into account the vacuum polarization of vector particles.

hep-ph↗

arXiv2001

Dirac-Kähler Equation (Review)

Tensor and matrix formulations of Dirac-Kähler equation for massive and massless fields are considered. The equation matrices obtained are simple linear combinations of matrix elements in the 16-dimensional space. The projection matrix-dyads defining all the 16 independent equation solutions are found. A method of computing the traces of 16-dimensional Petiau-Duffin-Kemmer matrix product is considered. It is shown that the symmetry group of the Dirac-Kähler tensor fields is SO(4,2). The conservation currents corresponding this symmetry are constructed. Supersymmetry of the Dirac-Kähler fields with tensor and spinor parameters is analyzed. We show the possibility of constructing a gauge model of interacting Dirac-Kähler fields where the gauge group is the noncompact group under consideration.

hep-th↗

arXiv1999

On exact solutions of the equation for a pion in external fields III

The exact solutions of the equation for a composite scalar particle which possesses electric and magnetic polarizabilities are found in an external uniform static magnetic field parallel to the direction of propagation of the quantized electromagnetic wave. As a particular case, the relativistic coherent states of a particle in the field of photons were considered. When the average photon number trends to infinity, the solution tends to the solution corresponding to the external classical electromagnetic wave with circular polarization.

hep-ph↗

arXiv1999

Pair production and solutions of the wave equation for particles with arbitrary spin

We investigate the theory of particles with arbitrary spin and anomalous magnetic moment in the Lorentz representation (0,s)X(s,0), in an external constant and uniform electromagnetic field. We obtain the density matrix of free particles in pure spin states. The differential probability of pair producing particles with arbitrary spin by an external constant uniform electromagnetic field has been found using the exact solutions. We have calculated the imaginary and real parts of the Lagrangian in an electromagnetic field that takes into account vacuum polarization.

hep-ph↗