相关论文: $n\bar{n}$ transitions in medium
The new model of $n\bar{n}$ transitions in the medium based on unitary $S$-matrix is considered. The time-dependence and corrections to the model are studied. The lower limit on the free-space $n\bar{n}$ oscillation time $\tau $ is in the…
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.…
The new model of $n\bar{n}$ transitions in nuclei based on unitary $S$-matrix is considered. The $|in>$-state of nucleus is described by single-particle shell model. The dynamical process part is calculated by means of field-theoretical…
The corrections to the model of $n\bar{n}$ transitions in the medium and additional baryon-number-violating processes are considered. We focus on the time-dependence since it is different for the $n\bar{n}$ transition followed by…
We show that there is a double counting in the standard model of $n\bar{n}$ mixing in the medium, resulting in full cancellation of leading terms. The direct calculation of $n\bar{n}$ transition, annihilation is performed. For lower limit…
It is shown that there is a double counting in the standard model of $n\bar {n}$ mixing in the medium, resulting in full cancellation of leading terms. The direct calculation of $n\bar{n}$ transition followed by annihilation is performed.…
Many experiments are currently looking for evidence of neutrino mass in the form of neutrino oscillations. Oscillation probabilities are non-linear functions of the neutrino mixing matrix elements, so most comparisons of data to theory are…
This is revision of the S-Matrix theory of neutrino oscillations used for many years. We evaluate the transition probability of a $\mu$ to $e$ neutrino without an approximation used for many theoretical studies, and find important…
We consider two-family neutrino oscillations in a medium of continuously-varying density as a limit of the process in a series of constant-density layers. We construct analytic expressions for the conversion amplitude at high energies…
We briefly outline the present state of the $n\bar{n}$ transition problem and compare two alternative models.
In this article, we reevaluate supernovae (SN) constraints on the diffusion time of neutrinos for a family of extensions of the Standard Model that incorporate new light scalar and vector mediators. We compute the neutrino mean free path,…
We consider the scattering matrices of massive quantum field theories with no bound states and a global $O(N)$ symmetry in two spacetime dimensions. In particular we explore the space of two-to-two S-matrices of particles of mass $m$…
We summarize our study of the neutron-antineutron transition in medium and nuclei in the framework of the field-theoretical approach. The models based on the diagram technique for direct reactions, potential description of…
We study the bar instability in collisionless, rotating, anisotropic, stellar systems, using N-body simulations and also the matrix technique for calculation of modes with the perturbed collisionless Boltzmann equation. These methods are…
We show in detail some results, outlined in a previous paper regarding the case of Brownian motion (BM), about the distribution of the $n$th-passage time of a one-dimensional diffusion obtained by a space or time transformation of BM,…
We study the unitary time evolution of a simple quantum Hamiltonian describing two harmonic oscillators coupled via a three-level system. The latter acts as an engine transferring energy from one oscillator to the other and is driven in a…
Consider the example of the relationship of the group O(3) of rotations in 3-space to the special unitary group SU(2). Given other unitary groups, what transformations can we find? In this paper we describe a method of constructing…
We expose a grave drawback hidden in the standard model of neutron-antineutron transitions in a medium. Correcting it, one improves a limit on the free-space neutron-antineutron oscillation time by 31 orders of magnitude.
A simple method of the calculation of neutrino transition probabilities in vacuum in the general case of $n$ massive neutrinos is presented. The method proposed fully utilizes the unitarity of the mixing matrix. Three-neutrino case for both…
We examine the reliability of the theoretical methods presently used for analysis and prediction of neutrino oscillation phenomena. Of particular interest are the limitations imposed by branch points when expansions in one of the small…