The role of positronium decoherence in the studies of positron annihilation in matter

摘要

A small difference between the energy of the para-positronium (p-Ps) andortho-positronium (o-Ps) states suggests the possibility of superposition ofp-Ps and o-Ps during the formation of positronium (Ps) from pre-Ps terminatingits migration in the matter in a void ('free volume'). It is shown that such asuperposition decohere in the basis of p-Ps and o-Ps and the decoherence timeis estimated. The time scale of the decoherence estimated here motivatesrespective correction in decomposition of the positron annihilation lifetimespectra. The way of the correction is sketched. The timescale of thedecoherence suggests a need of awareness when experimental data from positronannihilation techniques are processed. More generally, the superposited stateof Ps should contribute to the evolution theory of positronium in matter.