First observation of the unbound nucleus Ne 15

Abstract

We report on the first observation of the unbound proton-rich nucleus Ne15. Its ground state and first excited state were populated in two-neutron knockout reactions from a beam of 500 MeV/u Ne17. The Ne15 ground state is found to be unbound by 2.522(66) MeV. The decay proceeds directly to O13 with simultaneous two-proton emission. No evidence for sequential decay via the energetically allowed 2- and 1- states in F14 is observed. The Ne15 ground state is shown to have a strong configuration with two protons in the (sd) shell around O13 with a 63(5)% (1s1/2)2 component. © 2014 American Physical Society.