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Equation 11 · Part 2 · The Valley of Stability Is a Fitness Landscape

Symbol A^2/3

−aSA2/3-a_S A^{2/3}
A2/3A^{2/3}

What this part means

A2A^2/3 is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

A2A^2/3 is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

…neighbors, so binding energy grows roughly in proportion to the number of nucleons, the way a population’s raw fitness might scale with sheer numbers before any structural penalty is applied. The surface term, -aSa_S A2/3A^{2/3} , subtracts a cost proportional to surface area, because nucleons at the boundary have fewer neighbors to bind to — a tax on being exposed at the edge of the configuration, heaviest for small A where the surface-to-volume ratio is largest. The Coulomb term, -aCa_C Z(Z-1)/A1/3A^{1/3} , is a pure…

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An exponent tells how a base is used in multiplication. In x³, x is the base and 3 is the exponent: x³ = x × x × x.

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Sources cited in the article section

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