First observation of an isomeric state in proton drip-line nucleus 26P

Abstract

An isomeric state in the proton drip-line nucleus 26P has been observed by the γ-ray spectroscopy. The γ-ray energy and the half-life are 164.4 ± 0.1 keV and 120 ± 9 ns, respectively. For the isomeric transition of the mirror nucleus 26Na, the γ-ray energy of 82.40 ± 0.04 keV and the half-life of 4.35 ± 0.16 μs are also revised. Comparing the experimental reduced transition probabilities of 26Na and 26P with theoretical ones calculated by the shell model with the USDA interaction, the spin-parity (Jπ) of the isomeric state in 26P is most likely to be 1+. © Owned by the authors, published by EDP Sciences, 2014.