One and Two Photon Annihilation Processes in a Strong Magnetic Field

Abstract

<p>We present theoretical calculations of the annihilation rates for one and two photon decay of ground state positronium in a strong magnetic field, of order (10¹²-10¹³) Gauss such as assumed for neutron star surfaces. The calculation indicate that the one photon process at field of 10¹³ Gauss is of order (10ˉ⁴) compared to the two photon process. Consequently, a one photon annihilation line at 1.022 MeV is not expected in the spectra of neutron stars. The two photon rate is of order (5x10¹³ secˉ¹) at 10¹³ G; the half width is 43 keV. Thus, at such fields, the two photon line is fairly narrow and not smeared out through the magnetic field effects.</p>