News Excerpt:

A study recently published in Physical Review Letters Set out to find if one particularly unusual isotope, nitrogen-9, actually exists.

About Nitrogen-9:

• Nitrogen-9 isotope consists of seven protons and two neutrons – an unusually high proton-to-neutron ratio.
• This disparity critically affects the isotope’s stability, influencing its decay processes and overall behaviour.
• The high proton content places nitrogen-9 atoms beyond the conventional stability thresholds. 
• If all the atoms lived in a town where their location depended on their stability, nitrogen-9 would live outside the city, where no other atom lives.
• Physicists make sense of such stability limits using drip lines. The proton and neutron drip lines represent a boundary: add more particles beyond this boundary, and the nucleus becomes unstable. 
• They’re still working out the exact values at which the instabilities arise.

What are nuclides?

• A table or chart of nuclides is a two-dimensional graph of isotopes of the elements. One axis shows the number of neutrons (N), and the other shows the number of protons (Z) in each atomic nucleus. Each point on the graph denotes a nuclide.
• This way, scientists can understand the relationships between isotopes quickly. They also spot -
• Isotones (nuclides with the same number of neutrons), 
• Isobars (nuclides with the same total number of protons and neutrons but different individual numbers), 
• Isodiaphers (nuclides with the exact differences between their numbers of neutrons and protons).

What did the new study do?

• Their analysis revealed two distinct peaks among the nitrogen-9 resonant states that weren’t due to statistical fluctuations (or noise) in the data.
• These two resonant states refer to specific energy values at which a nucleus is particularly stable. In these states, specific nuclear reactions also become more likely than at other energies.
• The researchers corroborated their findings using a theoretical framework called the Gamow shell model. 
• This model studies systems maintained by weak bonds – such as an atomic nucleus whose proton and neutron numbers are close to the drip lines.
• The Gamow shell model predicted features for these resonant states aligned well with the structural features of a nitrogen-9 nucleus that the team had deduced from the invariant-mass spectrum.