arXiv subjects
Publications and source records attributed to Valeriy Nazaruk.
Particle oscillations in absorbing matter are considered. The approach based on the optical potential is shown to be inapplicable in the strong absorption region. Models with Hermitian Hamiltonian are analyzed. They give an increase of the process width in comparison with the model based on the optical potential.
It is shown that in the standard model of $K^0_{S}$ regeneration a system of noncoupled equations of motion is used instead of the coupled ones. A model alternative to the standard one is proposed. The calculation performed by means of diagram technique agrees with that based on exact solution of equations of motion.
It is shown that in the previous calculations of $K^0_{S}$ regeneration the noncoupled equations of motion have been considered instead of coupled one. We present the calculations based on the exact solution of coupled equations of motion and perturbation theory. The results differ radically from the previous ones.
$K^0\bar{K}^0$ transitions in a medium followed by decay and regeneration of $K^0_{S}$-component are considered by means of perturbation theory. It is shown that in the previous calculations the problem different from regeneration is solved.
We have performed the calculation of kaon regeneration based on the exact solution of equations of motion. The result differs radically from the previous one.
The applicability of the optical theorem in the models with the non-Hermitian Hamiltonian is studied. By way of example we consider the $n\bar{n}$ transition in a medium followed by annihilation. It is shown that an application of optical theorem for the non-unitary $S$-matrix leads to the qualitative error in the result. The lower limit on the free-space $n\bar{n}$ oscillation time $τ$ calculated by means of the model with Hermitian Hamiltonian lies in the range $10^{16}\; {\rm yr}>τ>1.2\cdot 10^{9}\; {\rm s}$.
It is shown that an application of optical theorem for the non-unitary S-matrix can lead to the qualitative error in the result.
It is shown that the self-energy of intermediate particles plays a crucial role in the particle oscillations in absorbing matter.
The present state of the $n\bar{n}$ transition problem is briefly outlined. The models based on the diagram technique for direct reactions, potential description of $\bar{n}$-medium interaction and field-theoretical approach are considered. It is shown that for the $n\bar{n}$ transition in medium field-theoretical approach should be used. The lower limit on the free-space $n\bar{n}$ oscillation time $τ_{\rm min}$ is found to be: $10^{16}\; {\rm yr}>τ_{\rm min}>1.2\cdot 10^{9}\; {\rm s}$.