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Author(s)
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Verney, D (Orsay, IPN) ; Testov, D (Orsay, IPN ; Dubna, JINR) ; Ibrahim, F (Orsay, IPN) ; Penionzhkevich, Yu (Dubna, JINR ; Moscow Phys. Eng. Inst.) ; Roussière, B (Orsay, IPN) ; Smirnov, V (Dubna, JINR) ; Didierjean, F (Strasbourg, IPHC) ; Flanagan, K (U. Manchester) ; Franchoo, S (Orsay, IPN) ; Kuznetsova, E (Dubna, JINR) ; Li, R (Orsay, IPN) ; Marsh, B (CERN) ; Matea, I (Orsay, IPN) ; Pai, H (Saha Inst.) ; Sokol, E (Dubna, JINR) ; Stefan, I (Orsay, IPN) ; Suzuki, D (Orsay, IPN) |
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Abstract
| We report on the β-delayed neutron emission probability (P1n) measurements of the Ga82,83,84 (N=51,52,53) precursors performed in one single experiment using the He3 neutron-counter TETRA at the ALTO facility in Orsay. Altogether our results for the three A=82,83, and 84 Ga precursors point towards a sizable P1n staggering in the N=50 region, similar to the one already observed just after the N=28 shell closure in the K isotopes chain, hinting at a similar mechanism. We will discuss the possible microscopic origin of this behavior, i.e., the existence in the light N=51 isotones of low-lying components of the so called pygmy Gamow-Teller resonance, already well established at Z=36, and persisting toward Ni79. |