Double-octupole states in 208Pb.

Area of Science:

• Nuclear Physics
• Quantum Mechanics
• Atomic Physics

Background:

• Understanding the nuclear structure of heavy, stable nuclei like lead-208 (208Pb) is crucial for nuclear physics.
• Previous models have had limitations in fully describing the complex excitation spectra and electromagnetic properties of 208Pb.

Purpose of the Study:

• To calculate the energy states of 208Pb using an advanced theoretical model.
• To validate the model by comparing calculated results with known experimental data for low-lying states and electromagnetic excitation strengths.
• To investigate the distribution and fragmentation of double-octupole excitation strength in 208Pb.

Main Methods:

• Utilized a 24-orbit model space for nuclear structure calculations.
• Included excitations up to two particles and two holes beyond the closed shell configuration.
• Calculated electromagnetic excitation strengths and double-octupole excitation patterns.

Main Results:

• The model successfully reproduced all known low-lying states of 208Pb.
• Observed distributions of electromagnetic excitation strength were well described by the model.
• Double-octupole excitation strength was found to be concentrated in specific 0+, 2+, and 4+ states around 5.2 MeV, and fragmented over many 6+ states, matching experimental results.

Conclusions:

• The employed nuclear model provides an accurate description of the low-lying states and electromagnetic properties of 208Pb.
• The calculated double-octupole excitation patterns align with recent experimental observations, validating the model's predictive power.
• This work enhances the understanding of nuclear structure and excitation mechanisms in heavy nuclei.