Pygmy Gamow-teller Resonance in the $N=50$ Region: new Evidence From Staggering of $\beta$-delayed Neutron-emission Probabilities Observed With Tetra

D. Verney (1) , B. Roussière (1) , F. Ibrahim (1) , S. Franchoo (1) , R. Li (1) , I. Matea (1) , I. Stefan (1) , D. Suzuki (1) , D. Testov , V. Smirnov , Yu. Penionzhkevich , E. Kuznetsova , E. Sokol , F. Didierjean (2) , H. Pai

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 IPHC - Institut Pluridisciplinaire Hubert Curien

We report on the P_n 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 P_n 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.

Mots clés: β-delayed neutron emission probabilities

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

D. Verney, B. Roussière, F. Ibrahim, S. Franchoo, R. Li, et al.. Pygmy Gamow-teller Resonance in the $N=50$ Region: new Evidence From Staggering of $\beta$-delayed Neutron-emission Probabilities Observed With Tetra. 8th International Symposium on Exotic Nuclei, Sep 2016, Kazan, Russia. pp.292-297, ⟨10.1142/9789813226548_0045⟩. ⟨hal-01646053⟩