Isospin mixing in nuclei within the nuclear density functional theory

Area of Science:

• Nuclear Physics
• Quantum Chromodynamics

Background:

• Isospin symmetry is a fundamental concept in nuclear physics, approximating the equality of proton and neutron masses and interactions.
• Deviations from perfect isospin symmetry, known as isospin violation, occur due to the Coulomb interaction and differing neutron and proton numbers.
• Understanding isospin mixing is crucial for precise nuclear structure calculations and interpreting experimental data.

Purpose of the Study:

• To perform a self-consistent, nonperturbative analysis of isospin mixing in atomic nuclei.
• To develop a method that eliminates unphysical isospin violation arising from neutron excess at the mean-field level.
• To investigate the dependence of isospin breaking on nuclear interaction parameters and its correlation with charge radii.

Main Methods:

• Employed the nuclear density functional approach for a self-consistent analysis.
• Utilized rediagonalization of the Coulomb interaction within the good-isospin basis.
• Investigated the impact of different nuclear interaction parametrizations.

Main Results:

• Successfully eliminated unphysical isospin violation present in mean-field calculations due to neutron excess.
• Demonstrated a significant dependence of the isospin-mixing magnitude on the chosen nuclear interaction parametrization.
• Observed a rough correlation between the isospin-mixing parameter and the difference between proton and neutron root-mean-square radii.

Conclusions:

• The presented method provides a more accurate description of isospin mixing by addressing unphysical violations.
• Nuclear interaction models significantly influence the degree of isospin breaking.
• The correlation between isospin mixing and charge radii differences offers insights into nuclear structure and symmetry breaking.