The shape of the xenon nucleus is no longer a mystery ⚡ экспресс
The correlation properties of the xenon-129 nucleus were quantitatively extracted from collider data using Bayesian inference. By merging a deformed rotor model, which captures the many-body dynamics of protons and neutrons, with hydrodynamic simulations of collision evolution, a global analysis of Xe-Xe and Pb-Pb events was performed. The shape of 129Xe was found to be nearly maximally triaxial, consistent with mean-field calculations for xenon isotopes away from closed shells. From the extracted ground-state information, two- and three-particle correlations were computed, imposing new constraints on ab initio nuclear theory. This establishes collider experiments as a pathway to quantitatively probe nucleon correlations driven by residual strong-force interactions.
Atomic nuclei are not always like billiard balls. Some are elongated, like cigars, others are flattened. But xenon-129 resembles a potato—a bumpy triaxial ellipsoid. To determine such a shape, physicists used a method reminiscent of colliding two lumps of dough: accelerating nuclei to near-light speeds and smashing them, they reconstruct the original geometry from the scattering of fragments.
Using data from the Large Hadron Collider and clever mathematical methods to account for uncertainties, the team found that the xenon nucleus is stretched almost maximally in three directions at once. This unexpectedly matched quantum calculations, confirming the correctness of the Standard Model. The most amazing thing is that such a nucleus does not just rest, but constantly tumbles, rotating around several axes, like a confused spinning top. This rotation produces a bizarre radiation pattern that can now be captured in experiments.
Thus, the collider becomes a kind of spectroscope, allowing a glimpse into the heart of the atom. The increase in disorder (entropy) during collisions is inevitable, but it's the price for unique information. The idea goes back to Rutherford and his followers Fermi and Bethe.
🎯 Triaxial nuclei, like quantum spinning tops, tumble in space, rotating around several axes at once. This creates an intricate pattern of their radiation.