K43(β−)Ca43and the structure ofK43andCa43

Abstract

The ${\beta }^{\mathrm{-}}$ decay of 22 h ${}_{}{}^{43}{}_{}{}^{}\mathrm{K}$ ($J^{\pi }$ ${=(3/2\mathrm{}}^{+}$) was reexamined with the main motive of determining the first-forbidden ${\beta }^{\mathrm{-}}$ branches to the ${(3/2\mathrm{}}^{\mathrm{-}}$ and ${(5/2\mathrm{}}^{\mathrm{-}}$ states more accurately. The branch to the ${(5/2\mathrm{}}^{\mathrm{-}}$ state at 373 keV was established as 0.9(6)% as opposed to a previous limit of <3%. Other ${\beta }^{\mathrm{-}}$ and γ branching ratios and γ-ray energies were determined with considerably improved accuracy. Shell-model calculations in full (2s,1d${)}^{24}$(1f,2p${)}^3$ and (2s,1d${)}^{23}$(1f,2p${)}^4$ configurational spaces were carried out using the WBMB spherical shell-model interaction. Energy spectra, nucleon pickup spectroscopic factors from ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$, two-nucleon transfer strengths from ${}_{}{}^{41}{}_{}{}^{}\mathrm{K}$, and γ-ray transition rates were calculated for both ${}_{}{}^{43}{}_{}{}^{}\mathrm{K}$ and ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ as well as allowed and first-forbidden decays for the known branches in ${}_{}{}^{43}{}_{}{}^{}\mathrm{K}$(${\beta }^{\mathrm{-}}$) ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$. Results are compared to experiment.