Sm Nucleus Exhibits SU(3) Rigid Triaxiality, Validating Theory with Experimental Energy Spectra and B(E2) Values

The structure of atomic nuclei often reveals surprising complexity, and recent evidence suggests that even seemingly well-understood nuclei may possess hidden features. Chunxiao Zhou, Xue Shang, and Tao Wang, from Hunan University of Arts and Sciences and Tonghua Normal University, investigate the nucleus of samarium, challenging the long-held belief that it exhibits simple axial symmetry. Their work demonstrates a significant degree of triaxiality, a deformation beyond simple elongation, using a newly developed theoretical framework called SU(3) symmetry. This research successfully reproduces experimental data concerning samarium’s energy levels, and its behaviour when absorbing energy, confirming the validity of the SU(3) approach and revealing a fundamental principle governing collective motions within nuclei.

Triaxiality and Shape Coexistence in Nuclei

This research investigates the complex shapes within atomic nuclei, specifically focusing on shape coexistence and triaxiality, a deviation from simple spherical or elongated forms. Scientists explore how nuclei can simultaneously exhibit multiple shapes and how this relates to the fundamental principles governing nuclear structure, utilizing the Interacting Boson Model (IBM) as a primary theoretical tool. The work centers on understanding nuclei that display both prolate and oblate shapes, and those exhibiting triaxial deformation, where the nucleus is distorted along three mutually perpendicular axes. A key focus is the investigation of how nuclei transition between different shapes and the role of symmetry principles in determining these configurations.

Researchers examine the properties of nuclei, such as their energy levels and the probabilities of electromagnetic transitions, to identify signatures of shape coexistence and triaxiality. The IBM serves as a framework for calculating these properties and comparing them with experimental observations, allowing scientists to refine their understanding of nuclear forces and structure. The research highlights the importance of SU(3) symmetry within the IBM, a mathematical principle that helps explain the observed triaxial shapes and γ-softness, a type of deformation where the nucleus easily changes its shape. Scientists are extending the IBM with higher-order interactions to better describe these complex shapes and improve the accuracy of theoretical predictions.

A recurring theme is the analysis of anomalies in the strength of electromagnetic transitions, which often signal the presence of shape coexistence or triaxiality. This work represents a significant advancement in nuclear physics, providing a deeper understanding of the forces that govern the structure of atomic nuclei. By combining theoretical calculations with experimental observations, scientists are unraveling the mysteries of nuclear shape evolution and gaining insights into the fundamental building blocks of matter. The research has implications for our understanding of the origin of elements in the universe and the properties of exotic nuclei found in astrophysical environments.

SU3-IBM Describes Samarium-154 Triaxiality

Scientists have successfully modeled the triaxial shape of the nucleus Samarium-154 using a newly developed theoretical framework called the SU3-IBM, an extension of the Interacting Boson Model. This research confirms that Samarium-154 exhibits a small degree of triaxiality and demonstrates the ability of the SU3-IBM to accurately describe this complex shape. The team sought to determine if the SU3-IBM, based on the principles of SU(3) symmetry, could reproduce the observed nuclear properties of Samarium-154. Researchers calculated key nuclear properties, including energy levels, the probabilities of electromagnetic transitions, and the distribution of electric charge.

These calculations were then rigorously compared with existing experimental data, providing a stringent test of the model’s accuracy. The results demonstrate a strong agreement between the theoretical predictions and the experimental measurements, confirming the validity of the SU3-IBM approach. Specifically, the calculated probabilities of electromagnetic transitions between low-lying energy levels showed significant improvements compared to predictions from other established models. This indicates that the SU3-IBM provides a more accurate description of the collective motions within the nucleus. The success of this model confirms the importance of SU(3) symmetry in understanding the structure of deformed nuclei and provides a framework for investigating the collective behavior of atomic nuclei.

SU3-IBM Confirms Triaxiality in Samarium-154

This research demonstrates the successful application of the SU3-IBM, a new theoretical framework, to describe the rigid triaxiality of the nucleus Samarium-154. Scientists confirmed that this nucleus exhibits a small degree of triaxial deformation and successfully modeled this shape using the SU(3) symmetry limit within the Interacting Boson Model. The model accurately reproduces key experimental data, including energy levels, the probabilities of electromagnetic transitions, and the distribution of electric charge. Researchers established a clear relationship between the model’s parameters and the SU(3) irreducible representations, providing a robust method for understanding the interplay between nuclear shape and symmetry.

This work offers insights into the collective behavior of atomic nuclei and contributes to a deeper understanding of the forces that govern their structure. While the study successfully models the rigid triaxiality, the authors acknowledge that further research is needed to explore more complex shapes and dynamics. This work lays the foundation for future investigations into the subtle interplay of forces shaping the structure of atomic nuclei. By accurately modeling the triaxial shape of Samarium-154, scientists are gaining valuable insights into the collective behavior of nuclear matter and advancing our understanding of the fundamental building blocks of matter. This research contributes to a more complete understanding of nuclear structure and the forces that govern the behavior of atomic nuclei. The ability to accurately model the triaxial shape of Samarium-154 provides valuable insights into the collective behavior of nuclear matter and has implications for our understanding of the origin of elements in the universe.