Evidence for Octupole Correlations in Multiple Chiral Doublet Bands.

Area of Science:

• Nuclear Physics
• Quantum Chromodynamics
• Particle Physics

Background:

• Understanding nuclear structure and electromagnetic transitions is crucial for nuclear physics.
• Chiral symmetry and octupole correlations are key phenomena in exotic nuclei.
• Previous studies have explored nuclear collectivity, but chiral geometry in octupole-soft nuclei remains less understood.

Purpose of the Study:

• To identify and characterize multiple chiral doublet bands in the ^{78}Br nucleus.
• To investigate the role of octupole correlations in the observed nuclear structures.
• To provide experimental evidence for chiral geometry in nuclei with soft octupole potential.

Main Methods:

• Experimental identification of positive- and negative-parity doublet bands in ^{78}Br.
• Analysis of eight strong electric dipole transitions linking yrast positive- and negative-parity bands.
• Theoretical interpretation using microscopic multidimensionally-constrained covariant density functional theory.
• Validation through triaxial particle rotor model calculations.

Main Results:

• Two pairs of positive- and negative-parity doublet bands were identified in ^{78}Br.
• Eight strong electric dipole transitions were observed, linking the yrast bands.
• The observed structures are interpreted as multiple chiral doublet bands with octupole correlations.
• Theoretical calculations support the interpretation of chiral geometry.

Conclusions:

• The study reports the first experimental observation of chiral geometry in octupole-soft nuclei, specifically in ^{78}Br.
• The findings confirm the presence of multiple chiral doublet bands and significant octupole correlations.
• This work advances the understanding of complex nuclear structures and symmetry breaking in atomic nuclei.