Amazing stuff!
"Just how long does a cluster of protons and neutrons have to stick together to count as an atomic nucleus? That’s the question raised by the observation of nitrogen-9, a fleeting nucleus that possesses seven protons and two neutrons, a ratio so lopsided that it fates the tiny knot of matter to fall apart almost instantly, in less than one-billionth of a nanosecond. Yet it still counts as a nucleus, physicists say, and explaining its existence and properties should help expand the horizons of nuclear theory and may even have deeper implications for quantum mechanics, the theory that governs the atomic world. ...
Such nuclei are pushing the boundaries of theory, he says. “This is totally new physics that needs to be addressed.” ...
No single theory can predict the existence, structure, and behavior of all atomic nuclei. In fact, nuclei are so complex that only the lightest ones can be described by models that take as their building blocks individual protons and neutrons and how they interact through the strong nuclear force. Even then, these models run into problems when describing light nuclei in which the protons dramatically outnumber the neutrons, or vice versa. ...
Nitrogen-9, the first nucleus known to spit out five protons, just barely qualifies as a nucleus ..."
Such nuclei are pushing the boundaries of theory, he says. “This is totally new physics that needs to be addressed.” ...
No single theory can predict the existence, structure, and behavior of all atomic nuclei. In fact, nuclei are so complex that only the lightest ones can be described by models that take as their building blocks individual protons and neutrons and how they interact through the strong nuclear force. Even then, these models run into problems when describing light nuclei in which the protons dramatically outnumber the neutrons, or vice versa. ...
Nitrogen-9, the first nucleus known to spit out five protons, just barely qualifies as a nucleus ..."
From the abstract:
"The boundaries of the Chart of Nuclides contain exotic isotopes that possess extreme proton-to-neutron 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."
Strong evidence for 9 N and the limits of existence of atomic nuclei (no public access and/or not published yet)
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