Strong evidence for 9N and the limits of existence of atomic nuclei
R.J. Charity🇺🇸 · J. Wylie🇺🇸 · S.M. Wang · T.B. Webb🇺🇸 · K.W. Brown🇺🇸 · G. Cerizza🇺🇸 · Z. Chajecki🇺🇸 · J.M. Elson🇺🇸 · J. Estee🇺🇸 · D.E.M Hoff🇺🇸 · S.A. Kuvin · W.G. Lynch🇺🇸 and 12 other authors
The boundaries of the Chart of Nuclides contain exotic isotopes that possess extreme proton-toneutron asymmetries. Here we report on strong evidence of 9N, one of the most exotic proton-rich isotopes where more than one half of its constitute nucleons are unbound. With seven protons and two neutrons, this extremely proton-rich system would represent the first-known example of a ground-state five-proton emitter. The invariant-mass spectrum of its decay products can be fit with two peaks whose energies are consistent with the theoretical predictions of an open-quantum-system approach, however we cannot rule out the possibility that only a single resonance-like peak is present in the spectrum.