The pair formation has for a long time both been studied experimentally  and been subject to theoretical analysis .
In this paper an attempt is made to understand the elementary electron-positron pair formation process in terms of a revised quantum electrodynamic theory and its application to a wave-packet model of the individual photon [3, 4, 5, 6].
Since the experiments clearly reveal the pair formation to take place within a small region of space, the incoming photon should have a strongly limited extension in its radial (transverse) direction, thus having the character of "needle radiation".
There are three conservation laws to be taken into account in the pair formation process.
The present approach to the pair formation process has some similarity with the breaking of the stability of vacuum by a strong external electric field, as being investigated by Fradkin et al.
Male urine release was necessary for stable pairing, suggesting that male urine signals may be involved in pair maintenance rather than pair formation.
Blue crab courtship can be divided into three phases: mate attraction, pair formation, and pair maintenance.
In this study, the occurrence and variability of courtship behaviors observed during blue crab pair formation were examined.
Pairing was initiated at a high rate, however (82% of trials), with 50% of trials resulting in Stable Pair Formation.
Most pairs (18 of 22) exhibited some sequence of courtship behaviors prior to pair formation ([X.