Simultaneous Microscopic Description of Nuclear Level Density and Radiative Strength Function.

Area of Science:

• Nuclear Physics
• Quantum Mechanics
• Statistical Mechanics

Background:

• Nuclear level density (NLD) and radiative strength function (RSF) are fundamental nuclear structure properties.
• Accurate theoretical models are needed to describe these properties across various isotopes and energy ranges.
• Previous models often relied on approximations that may not hold universally.

Purpose of the Study:

• To simultaneously describe NLD and RSF using a unified microscopic approach.
• To investigate the role of exact thermal pairing and giant resonances in nuclear properties.
• To validate the model against experimental data for specific isotopes.

Main Methods:

• A microscopic approach incorporating thermal effects of exact pairing.
• Inclusion of giant resonances within the phonon-damping model.
• Comparison of theoretical calculations with experimental data from the Oslo group for Ytterbium isotopes.

Main Results:

• The model successfully describes NLD and RSF for ^{170,171,172}Yb isotopes.
• Demonstrates the significance of exact thermal pairing for NLD at low and intermediate excitation energies.
• Results challenge the validity of the Brink-Axel hypothesis for RSF calculations.

Conclusions:

• Exact thermal pairing is essential for accurate NLD predictions.
• The developed microscopic approach provides a robust framework for studying nuclear properties.
• The findings necessitate a re-evaluation of assumptions in current RSF models.