Positronium in a liquid phase: formation, bubble state and chemical reactions

This chapter reviews the following items: 1. Energy deposition and track structure of fast positrons: ionization slowing down, number of ion-electron pairs, typical sizes, thermalization, electrostatic interaction between e+ and its blob, effect of local heating; 2. Positronium formation in condensed media: the Ore model, quasifree Ps state, intratrack mechanism of Ps formation; 3. Fast intratrack diffusion-controlled reactions: Ps oxidation and ortho-para conversion by radiolytic products, reaction rate constants, interpretation of the PAL spectra in water at different temperatures; 4. Ps bubble models. "Non-point" positronium: wave function, energy contributions, relationship between the pick-off annihilation rate and the bubble radius

Renormalized non-modal theory of the kinetic drift instability of plasma shear flows

The linear and renormalized nonlinear kinetic theory of drift instability of plasma shear flow across the magnetic field, which has the Kelvin's method of shearing modes or so-called non-modal approach as its foundation, is developed. The developed theory proves that the time-dependent effect of the finite ion Larmor radius is the key effect, which is responsible for the suppression of drift turbulence in an inhomogeneous electric field. This effect leads to the non-modal decrease of the frequency and growth rate of the unstable drift perturbations with time. We find that turbulent scattering of the ion gyrophase is the dominant effect, which determines extremely rapid suppression of drift turbulence in shear flow

Formation of quasi-free and bubble positronium states in water and aqueous solutions

It is shown that in aqueous solutions a positronium atom is first formed in the quasi-free state, and, after 50-100 ps, becomes localized in a nanobubble. Analysis of the annihilation spectra of NaNO3 aqueous solutions shows that the hydrated electron is not involved in the positronium (Ps) formation

Semiclassical treatment of logarithmic perturbation theory

The explicit semiclassical treatment of logarithmic perturbation theory for the nonrelativistic bound states problem is developed. Based upon $\hbar$-expansions and suitable quantization conditions a new procedure for deriving perturbation expansions for the one-dimensional anharmonic oscillator is offered. Avoiding disadvantages of the standard approach, new handy recursion formulae with the same simple form both for ground and exited states have been obtained. As an example, the perturbation expansions for the energy eigenvalues of the harmonic oscillator perturbed by $\lambda x^{6}$ are considered.Comment: 6 pages, LATEX 2.09 using IOP style

Effects of local heating and premelting in the terminal part of the e+^+ track

Due to the ionizations promoted by the slowing down of energetic positron and subsequent ion-electron recombinations, positron releases up to 1 keV in the terminal blob region [1]. After all this energy converts into heat. This local heating effect makes the medium to heat up and melt, especially at the region where the bulk temperature of the medium is close (but slightly below) the phase transition temperature. In this case this effect leads to a peculiar temperature dependence of the lifetime of the long-lived LT spectra component. We introduce a model to describe the temperature behaviour of the ortho-positronium lifetime for three simple alcohols (methanol, ethanol and butanol) at the melting range

Operational indistinguishably of varying speed of light theories

The varying speed of light theories have been recently proposed to solve the standard model problems and anomalies in the ultra high energy cosmic rays. These theories try to formulate a new relativity with no assumptions about the constancy of the light speed. In this regard, we study two theories and want to show that these theories are not the new theories of relativity, but only re-descriptions of Einstein's special relativity.Comment: 5 pages, 2 figures, title changed, minor changes in notations and formulae, a paragraph added, Int. J. Mod. Phys. D (in press) v

The evidence of quasi-free positronium state in GiPS-AMOC spectra of glycerol

We present the results of processing of Age-Momentum Correlation (AMOC) spectra that were measured for glycerol by the Gamma-induced positron spectroscopy (GiPS) facility. Our research has shown that the shape of experimental s(t) curve cannot be explained without introduction of the intermediate state of positronium (Ps), called quasi-free Ps. This state yields the wide Doppler line near zero lifetimes. We discuss the possible properties of this intermediate Ps state from the viewpoint of developed model. The amount of annihilation events produced by quasi-free Ps is estimated to be less than 5% of total annihilations. In the proposed model, quasi-free Ps serves as a precursor for trapped Ps of para- and ortho-states