The direct positron annihilation during a collision in a gas was investigated. From the evolution of a wave packet with a time width much shorter than the Ps lifetime, the cross section of direct annihilation was calculated, where the direct contribution was extracted through the time dependence of survival probability. It was found that the cross section obtained for hydrogen atom was enhanced in energies around 10 eV well above the Ps formation threshold voltage.
|Number of pages||4|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 2003 May|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics