Delocalization in the hot deformed hypernucleus $_{\Lambda }^{21}Ne$

How Temperature Reshapes Hypernuclear Structure

Hyperons are believed to be abundant in the dense inner regions of neutron stars, where matter exists at extremely high temperatures and densities. To better understand how hypernuclei behave under such extreme conditions, researchers employ the finite-temperature Skyrme–Hartree–Fock model to simulate the effects of elevated temperatures on their structure. In this study, they focus on the hypernucleus ²¹_ΛNe, a system known for its strong deformation and pronounced clustering at low temperature. At low temperatures, the nucleus exhibits a pronounced elongation along one axis (quadrupole deformation) and clear α-cluster structures, where nucleons group into localized clusters. As temperature rises, these structural features gradually evolve, with clustering fading and the nucleus adopting a more uniform shape.

Thermal Suppression of Clustering

Finite-temperature calculations demonstrate that the strong clustering and deformation of ²¹_ΛNe  gradually diminish as temperature increases. Around 2.8 MeV, nucleonic clusters disappear entirely as thermal excitations weaken the nuclear deformation and distribute nucleons more evenly throughout the nucleus. The embedded Λ hyperon responds even more strongly, expanding rapidly and highlighting the sensitivity of hypernuclear structure to temperature.

Hyperon Delocalization: A Distinctive Response to Temperature 

A particularly striking finding concerns the behavior of a Λ hyperon embedded in the nucleus ²⁰Ne. Compared to nucleons, the hyperon’s spatial distribution responds more sensitively to temperature. Because hyperons are not subject to the Pauli exclusion principle with respect to nucleons within the nucleus, they possess a lower excitation threshold. As temperature rises, the hyperon wave function expands rapidly, leading to pronounced delocalization well before similar effects appear for nucleons.

“Our results show that a hyperon acts as an especially sensitive probe of thermal effects in nuclear system,” the authors note.

Implications for Hypernuclear Physics and Astrophysics

Understanding how temperature influences localization and clustering in hypernuclei is essential for interpreting experiments in relativistic heavy-ion collisions, where hypernuclei are produced under extreme conditions.

Beyond the laboratory, the findings are also relevant to astrophysical environments such as neutron stars and supernovae, where hot, dense matter containing strange particles may exist. The study provides new constraints on hyperon–nucleon interactions and contributes to improving theoretical descriptions of hot nuclear matter.

Advancing Nuclear Physics Research

The researchers plan to extend their investigations to other hypernuclear systems and systematically explore how temperature influences nuclear deformation, localization, and clustering within a unified mean-field framework.

“By revealing how temperature suppresses clustering and enhances delocalization in hypernuclei, this work deepens our understanding of nuclear matter under extreme conditions,” stated Professor Zhou.

The complete study is via by DOI:  https://doi.org/10.1007/s41365-025-01875-1