Two mass rules in the three-body problem: the regular encounter and the exit from chaos

We investigate how the masses decide who is ejected in the planar three-body problem with zero total angular momentum. In a single regular encounter, in 28 mass combinations and 24,316 runs, exchange takes place when the incoming body has more than about half the mass of the heavier binary member, according to a two-parameter curve that explains 94% of the variation and holds for mass ratios not used in the fit; who leaves the pair, when there is an exchange, is almost a coin toss, even with a member ten times lighter. With the incoming body of the same mass as the heavier member, a Newton's cradle effect expels that member in about one third of the cases. In the chaotic phases, in 13 mass sets, the fraction of exits of each body follows the flux factor of Kol's theory, which favors the lightest body, with a mean error of 0.035. The exits of the light body are definitive in 17% to 46% of the cases, against about 10% for the heavy ones, and this filter explains why the light body is the final ejected body in the vast majority of systems.