TY - JOUR
T1 - Enhancement of direct positron annihilation due to temporal capture by an atom
AU - Yamanaka, Nobuhiro
AU - Kino, Yasushi
AU - Takano, Yasushi
AU - Kudo, Hiroshi
AU - Ichimura, Atsushi
PY - 2003
Y1 - 2003
N2 - We investigate direct positron annihilation during a collision in a gas; this is physically separable from indirect annihilation, i.e., via formation of positronium (Ps) and its decay. The cross section of direct annihilation is calculated from the evolution of a wave packet with a time width much shorter than the Ps lifetime, where the direct contribution is extracted through the time dependence of the survival probability. The cross section obtained for a hydrogen atom is found to be enhanced in energies around 10 eV well above the Ps formation threshold. This enhancement is shown to be due to temporal positron capture with electronic excitation in the atom.
AB - We investigate direct positron annihilation during a collision in a gas; this is physically separable from indirect annihilation, i.e., via formation of positronium (Ps) and its decay. The cross section of direct annihilation is calculated from the evolution of a wave packet with a time width much shorter than the Ps lifetime, where the direct contribution is extracted through the time dependence of the survival probability. The cross section obtained for a hydrogen atom is found to be enhanced in energies around 10 eV well above the Ps formation threshold. This enhancement is shown to be due to temporal positron capture with electronic excitation in the atom.
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U2 - 10.1103/PhysRevA.67.052712
DO - 10.1103/PhysRevA.67.052712
M3 - Article
AN - SCOPUS:84871570110
SN - 1050-2947
VL - 67
SP - 4
JO - Physical Review A - Atomic, Molecular, and Optical Physics
JF - Physical Review A - Atomic, Molecular, and Optical Physics
IS - 5
ER -