Polarization Effects in the Two-Quantum Annihilation of Positrons

Abstract

Computations of two-quantum annihilation-in-flight of a positron with an electron are made with little averaging of spins or summing of photon polarizations. For energies of a few Mev, strong departures are found from the better known situation at vanishing energy, as regards annihilation probability for parallel spins, the plane-polarization correlation, and the circular-polarization correlation. Production of a circularly polarized photon beam is discussed, as is longitudinal- or transverse-polarization analysis by a polarized electron target.