Shell Evolution towards ^{78}Ni: Low-Lying States in ^{77}Cu.

Area of Science:

• Nuclear Physics
• Atomic and Molecular Physics
• Spectroscopy

Background:

• Investigating the nuclear structure of neutron-rich isotopes is crucial for understanding nuclear forces.
• The ^{78}Ni region is of particular interest due to its proximity to a doubly magic nucleus.

Purpose of the Study:

• To investigate the level structure of the neutron-rich ^{77}Cu nucleus.
• To identify new excited states and construct a level scheme for ^{77}Cu.
• To evaluate the single-particle structure near ^{78}Ni.

Main Methods:

• Utilized beta-delayed gamma-ray spectroscopy.
• Produced ^{77}Ni ions via in-flight fission at the RIKEN Nishina Center.
• Employed the BigRIPS fragment separator, WAS3ABi silicon detector array, and EURICA germanium cluster detector array.

Main Results:

• Identified a large number of excited states in ^{77}Cu for the first time.
• Constructed a level scheme for ^{77}Cu based on coincidence relationships.
• Observed good agreement between experimental data and large-scale Monte Carlo shell model calculations.

Conclusions:

• The study provides a detailed level scheme for ^{77}Cu.
• Experimental results support theoretical predictions regarding nuclear structure near ^{78}Ni.
• Suggests a single-particle nature for specific states in ^{77}Cu, shedding light on the doubly magic nature of ^{78}Ni.