What does this equation mean?

Further out still, past the drip lines entirely in the sense of ordinary particle stability, theoretical models predict a second region of enhanced binding among the superheavy elements — the island of stability — centered on a closed neutron shell now generally predicted near N=184 , well beyond any neutron number reached by nuclei observed to date. As Yuri Oganessian, who led much of the experimental program that produced the heaviest known elements, and Krzysztof Rykaczewski put it in a 2015 review, current experiments reach only as far as N=177 , and “modern theoretical approaches, supported by new experimental data, also point to the existence of long-lived nuclei at and around the magic neutron number N=184 ” — a prediction, not yet a measurement [ 8 ] . The same review is candid about the gap between prediction and observation: some models predict half-lives reaching a million years, or longer, for hypothetical nuclei sitting on that island’s peak, while every superheavy decay chain actually observed so far has terminated in spontaneous fission, with measured half-lives ranging from a fraction of a millisecond to a little over a day. The discovery of element 118 — later named oganesson, symbol Og, by the International Union of Pure and Applied Chemistry in 2016 in recognition of Oganessian’s contributions [ 14 ] — was reported in 2006 from the fusion of californium-249 with calcium-48 projectiles at the Joint Institute for Nuclear Research, producing the isotope now known as oganesson-294 through the evaporation of three neutrons from the compound system [ 7 ] . Oganesson-294 sits nowhere near the predicted island’s peak; it is a beachhead on its near shore, produced one atom at a time, each one confirmed only by the alpha-decay chain it leaves before undergoing spontaneous fission. The island of stability is, at present, entirely a predicted peak: real in the sense that a well-established theoretical structure predicts it, unreached in the sense that no experiment has weighed a nucleus anywhere near its summit.