Beta decay of 71,73Co; probing single particle states approaching doubly magic 78Ni

TL;DR

This study investigates low-energy excited states in 71,73Ni via beta decay of 71,73Co, constructing level schemes and analyzing shell model states to understand single particle behavior near the doubly magic 78Ni nucleus.

Contribution

The paper provides detailed level schemes of 71,73Ni and identifies specific states and isomers, advancing understanding of nuclear structure approaching 78Ni.

Findings

Identification of 5/2- states from the f5/2 orbital

Detection of positive parity states from the g9/2 orbital

Beta-delayed neutron branching ratios for 71,73Co

Abstract

Low-energy excited states in 71,73Ni populated via the {\beta} decay of 71,73Co were investigated in an experiment performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). Detailed analysis led to the construction of level schemes of 71,73Ni, which are interpreted using systematics and analyzed using shell model calculations. The 5/2- states attributed to the the f5/2 orbital and positive parity 5/2+ and 7/2+ states from the g9/2 orbital have been identified in both 71,73Ni. In 71Ni the location of a 1/2- {\beta}-decaying isomer is proposed and limits are suggested as to the location of the isomer in 73Ni. The location of positive parity cluster states are also identified in 71,73Ni. Beta-delayed neutron branching ratios obtained from this data are given for both 71,73Co.