Pygmy Gamow-teller Resonance in the $N=50$ Region: new Evidence From Staggering of $\beta$-delayed Neutron-emission Probabilities Observed With Tetra
Résumé
We report on the Pn measurements of the 82,83,84Ga (N = 51, 52, 53) precursors performed in one single experiment using the 3He neutron-counter TETRA at the ALTO facility in Orsay. Altogether our results for the three A = 82, 83 and 84 Ga isotopes point towards a sizable Pn staggering in the N = 50 region, similar to the one already known in the N = 28 region, hinting at a similar mechanism. We will discuss the possible microscopic origin of this behavior i.e. the existence in the N = 50 region of a low-lying component of the so called Pygmy Gamow-Teller Resonance, already well established at Z = 36, and persisting towards 78Ni.