Isospin Mixing in ^{80}Zr: From Finite to Zero Temperature

Area of Science:

• Nuclear Physics
• Nuclear Reactions
• Isospin Physics

Background:

• Isospin symmetry is a fundamental concept in nuclear physics, providing insights into nuclear structure and forces.
• Giant dipole resonance (GDR) is a key probe of nuclear properties, including isospin mixing.
• Understanding isospin symmetry breaking is crucial for precise nuclear structure calculations and interpretations.

Purpose of the Study:

• To deduce isospin mixing in the ^{80}Zr compound nucleus at a specific excitation energy.
• To investigate the temperature dependence of isospin mixing.
• To extract the isospin-symmetry-breaking correction (δC) and compare it with existing data.

Main Methods:

• Formation of the ^{80}Zr compound nucleus using two different heavy-ion fusion reactions: ^{40}Ca+^{40}Ca and ^{37}Cl+^{44}Ca.
• Detection of gamma rays from the giant dipole resonance decay using the AGATA demonstrator array and LaBr_{3}:Ce detectors.
• Analysis of gamma-ray spectra to determine isospin mixing and extract nuclear temperature.

Main Results:

• Isospin mixing was successfully deduced in the ^{80}Zr compound nucleus at an excitation energy of 54 MeV.
• The temperature dependence of isospin mixing was determined, allowing for the extrapolation to a zero-temperature value.
• The isospin-symmetry-breaking correction (δC) was extracted and found to be consistent with values obtained from beta-decay data.

Conclusions:

• The study provides valuable experimental data on isospin mixing in medium-mass compound nuclei.
• The extracted isospin-symmetry-breaking correction supports theoretical models and experimental observations from other nuclear processes.
• This work contributes to a deeper understanding of fundamental symmetries in atomic nuclei.