A many-body theory approach developed by the authors [Phys. Rev. A 70 032720 (2004)] is applied to positron bound states and annihilation rates in atomic systems. Within the formalism, full account of virtual positronium (Ps) formation is made by summing the electron-positron ladder diagram series, thus enabling the theory to include all important many-body correlation effects in the positron p...

We compile the most recently measured and calculated cross sections for processes relevant to annihilation of positrons in solar flares and present the final evaluated cross sections. We calculate the 511 keV annihilation line spectrum and relative strength of the 3γ continuum for each of the annihilation processes, using a Monte Carlo code that simulates the thermalization of and positronium p...