Observations of the Gamow-Teller resonance in the rare-earth nuclei aboveGd146populated inβdecay

Abstract

The rare-earth region of the nuclear table around the quasi-doubly magic nucleus $^{146}\text{Gd}$ is one of the very few places in which the Gamow-Teller (GT) resonance can be populated in $\ensuremath{\beta}$ decay. The appropriate technique to study such a phenomenon is total absorption spectroscopy, thanks to which one can measure the $B$(GT) distribution in $\ensuremath{\beta}$-decay experiments even when it is very fragmented and lies at high excitation energy in the daughter nucleus. Results on the GT resonance measured in the $\ensuremath{\beta}$ decay of the odd-$Z, N=83$ nuclei $^{148}\text{Tb}, ^{150}\text{Ho}$, and $^{152}\text{Tm}$ are presented in this work and compared with shell-model calculations. The tail of the resonance is clearly observed up to the limit imposed by the $Q$ value. This observation is important in the context of the understanding of the ``quenching'' of the GT strength.