Decay Characteristics of Neutron Excess Potassium Nuclei

In neutron star mergers, neutron excess nuclei and the r-process are important factors governing the production of heavy nuclear systems. A single-particle model evaluation of potassium nuclei suggests that the heaviest Z = 19 nucleus will have mass 69 with filling of the 1g9/2 neutron shell. A = 55 – 69 potassium isotopes have limited experimental half-life data, but the model predicts beta decay half-lives in the range of 0.315 – 9.23 ms. Based on previous calculations for Z = 9 - 18, 20, 26, and 30 systems and comparisons to the 55K – 59K, 61K, and 63K calculations, summarized in the Japanese Nuclear Data Compilation, the single-particle model results likely overestimate the half-lives of A = 55 – 69 neutron excess potassium nuclei.