Annihilation into two photons of lepton pairs including anomalous magnetic moment and polarization effects

Abstract

The high-energy y-ray source from electron-positron pair annihilation has been discussed by several authors (~,2) and looks most attractive for the bubble chamber (3.~). The use of magnetized supermendur foil (~) for polarized electrons will make it possible to obtain polarized high-energy photons from the pair-annihilation process. GATTO (~) analysed the two-quantum annihilation of the electron-positron pair, including a form factor to test qnantum electrodynamics with colliding-beam experiments. The purpose of this note is to report the results of a calculation of matrix elements for annihilation into two photons of lepton pairs with anomalous magnetic moment and polarization effects taken into account. A form factor which can be thought of as a product of a form factor for the vertex and a form factor for the propagator (6) is also included. The mass terms which are usually omitted not without justification for high-energy lepton pairs are included in the present calculation so that the results can be applied to both lowand high-energy experiments. The matrix elements for annihilation into two photons of a lepton pair with anomalous magnetic moments are given by