Related papers: Annihilation-Gamma-based Diagnostic Techniques for…
We study the initial properties and positron annihilation within a small electron-positron plasma drop formed by intense laser pulse. Such QED cascade initiated plasma is, in general, far below the chemical (particle yield) equilibrium. We…
Gamma-Ray Bursts are among the most powerful events in the Universe. Despite half a century of observations of these transient sources, many open questions remain about their nature. Polarization measurements of the GRB prompt emission have…
An explicit positronium (Ps) source model was implemented in Geant4 to provide direct event-level control over annihilation channel selection, decay timing, and photon emission topology. The implementation supports direct annihilation,…
Linear polarization in X- and gamma-rays is an important diagnostic of many astrophysical sources, foremost giving information about their geometry, magnetic fields, and radiation mechanisms. However, very few X-ray polarization…
The advent of back-scattered laser beams for electron-positron colliders will allow detailed studies of a large array of high energy photon-photon and photon-electron collision processes with polarized beams. These include tests of…
Spectroscopic investigations of the properties of a plasma produced by a flashboard plasma source, commonly used in pulsed plasma experiments, are presented. The plasma is used to prefill a planar 0.4-ms-conduction time plasma opening…
Recent preliminary results from the PAMELA experiment indicate the presence of an excess of cosmic ray positrons above 10 GeV. In this letter, we consider possibility that this signal is the result of dark matter annihilations taking place…
Gamma-ray lines from cosmic sources provide unique isotopic information, since they originate from energy level transitions in the atomic nucleus. Gamma-ray telescopes explored this astronomical window in the past three decades, detecting…
Positron physics touches on a wide-ranging variety of fields from materials science to medical imaging to high energy physics. In this paper we present the development of a flexible positron annihilation spectrometer appropriate for the…
The properties of low-frequency convective fluctuations and transport are investigated for the boundary region of magnetized plasmas. We employ a two-dimensional fluid model for the evolution of the global plasma quantities in a geometry…
If dark matter decays or annihilates into electrons and positrons, it can affect radiation and cosmic-ray backgrounds. We review a novel, more general analysis of constraints on decaying dark matter models, by introducing the response…
We present a new approach in modelling the polarized Galactic synchrotron emission in the microwave range (20-100 GHz), where this radiation is expected to play the leading role in contaminating the Cosmic Microwave Background (CMB) data.…
We discuss gamma-ray signatures associated with an asymmetric explosion and transport of positrons in SN Ia ejecta. In particular, Compton scattering of gamma-ray line photons can induce polarization in the continuum, which would be a…
The aim of this work is to identify the mechanisms responsible for very large rates and other peculiarities observed in low-energy positron annihilation on molecules. The two mechanisms considered are: (i) Direct annihilation of the…
Numerical simulations of radiative processes in magnetized compact sources such as hot accretion disks around black holes, relativistic jets in active galaxies and gamma-ray bursts are complicated because the particle and photon…
The detection of non-baryonic dark matter through its gamma-ray annihilation in the centre of our galaxy has been studied. The gamma fluxes according to different models have been simulated and compared to those expected to be observed with…
In this paper, electromagnetic emissions produced in a thin beam-plasma system are studied using two-dimensional particle-in-cell simulations. For the first time, the problem of emission generation in such a system is considered in the…
Two different model-independent mapping techniques have been applied to OSSE, SMM, TGRS and balloon data and reveal a feature in the 0.511 MeV electron-positron annihilation radiation pattern of our galaxy centered roughly at l=-2 deg. and…
Proton radiography is a widely-fielded diagnostic used to measure magnetic structures in plasma. The deflection of protons with multi-MeV kinetic energy by the magnetic fields is used to infer their path-integrated field strength. Here, the…
We present a novel determination of the astrophysical uncertainties associated to the secondary antiproton flux originating from cosmic-ray spallation on the interstellar gas. We select a set of propagation models compatible with the recent…