Why is ${\rm Pb}^{208}$ the heaviest stable nuclide?

TL;DR

This paper develops an effective theory linking low-energy quantum chromodynamics to nuclear stability, proposing a duality with black holes to explain why lead-208 is the heaviest stable nucleus.

Contribution

It introduces a novel gauge/gravity duality approach to nuclear physics, connecting quark dynamics with black hole analogies to explain nuclear stability limits.

Findings

Maximal number of protons in stable nuclei is approximately 82.

Explains the quark composition differences in light and heavy stable nuclei.

Proposes a duality between nuclear stability and extremal black holes.

Abstract

In an effort to understand nuclei in terms of quarks we develop an effective theory to low-energy quantum chromodynamics in which a single quark contained in a nucleus is driven by a mean field due to other constituents of the nucleus. We analyze the reason why the number of $d$ quarks in light stable nuclei is much the same as that of $u$ quarks, while for heavier nuclei beginning with ${\rm Ca}^{40}$, the number of $d$ quarks is greater than the number of $u$ quarks. To account for the finiteness of the periodic table, we invoke a version of gauge/gravity duality between the dynamical affair in stable nuclei and that in extremal black holes. With the assumption that the end of stability for heavy nuclei is dual to the occurrence of a naked singularity, we find that the maximal number of protons in stable nuclei is $Z_{\max}^{\rm H}\approx 82$.