Positron emission tomography (PET) offers a number of unique advantages compared to other imaging modalities. PET measures the two annihilation photons that are produced back-to-back after positron emission from a radionuclide tagged tracer molecule, which is chosen to mark a specific function in the body on a biochemistry level (Fig. 1). Hence PET provides molecular imaging of biological funct...

We show the impact of the electroweak, and in one instance the QCD, one-loop corrections on the relic density of dark matter in the MSSM which is provided by the lightest neutralino. We cover here some of the most important scenarii: annihilation into fermions for a bino-like neutralino, annihilation involving gauge bosons in the case of a mixed neutralino, the neutralinostau co-annihilation re...

The effects of the positron (e(+)) annihilation in e(+) scattering by the H atom are included directly in the Hamiltonian as an absorption potential, and hence the finite lifetimes Gamma(ns) of positronium (Ps) in states ns are automatically taken account of. The Schrödinger equation is solved using the hyperspherical close-coupling method. The annihilation and Ps formation are shown to be inse...

A new theoretical framework for computation of the relic abundance of cold dark matter particles such as LSP is presented and some generic features of new results are discussed. The most important is a generalization of the Boltzmann equation to include off-shell effects and its thermal average over cosmic medium. It is shown that at very low temperatures, much below the mass of annihilating pa...

Pair annihilation of heavy stable particle that occurs in the early universe is investigated, and quantum kinetic equation for the momentum distribution of the annihilating particle is derived, using the influence functional method. A bosonic field theory model is used to describe the pair annihilation in the presence of decay product particles making up a thermal environment. A crossing symmet...

Congestion control in the signaling system number 7 (SS7) is a necessity to fulfil the requirements of a telecommunication network that satisfy customers’ requirements on quality of service. Heavy network load is an important source of customer dissatisfaction as congested networks result in deteriorated quality of service. With the introduction of a Congestion Control Mechanism (CCM), that ann...

The injection of secondary particles produced by dark annihilation around redshift ∼ 1000 would inevitably affect the process of recombination, leaving an imprint on cosmic microwave background (CMB) temperature and polarization anisotropies. We show that the most recent CMB measurements provided by the WMAP satellite mission and the ACT telescope place interesting constraints on DM self-annihi...

Clusters of galaxies are enriched with positrons from jets of active galactic nuclei (AGNs) or from the interaction of cosmic-rays with the intracluster gas. We follow the cooling of these positrons and show that their eventual annihilation with cluster electrons yields a narrow annihilation line. Unlike annihilation in the interstellar medium of galaxies, the line produced in clusters is not s...

We present a model of weak scale dark matter (DM) where the thermal DM density is set by the lepton asymmetry due to the presence of higher dimension lepton violating operators. In these models there is generically a separation between the annihilation cross section responsible for the relic abundance (through lepton violating operators) and the annihilation cross section that is relevant for t...

We found new current-field equations including charge creation-annihilation fields. Although it is difficult to treat creation and annihilation of charge pairs for Maxwell’s equations, the new equations easily treat them. The equations cause the confinement of charge creation and annihilation centers, which means the charge conservation for this model. The equations can treat not only electroma...