‘Strong evidence’ unusual nitrogen-9 nucleus exists, scientists say Premium

Physicists studied nitrogen-9, an unusually high proton-to-neutron-ratio isotope, to check if it exists. Using a sophisticated setup, they bombarded an energised beam of oxygen-13 atoms at a target composed of beryllium-9 atoms. The team studied the collision debris, produced by fragmentation reactions, using a high-resolution array comprising 14 detectors. Using the invariant mass technique, they were able to find strong evidence of the existence of the nitrogen-9 nucleus, challenging previous interpretations of nuclear structure.

There are 118 elements. Each element is unique by virtue of the different numbers of electrons, protons, and neutrons its atoms contain.

Isotopes are atoms of a given element that vary only in the number of neutrons. This difference sets apart one isotope from another. Many isotopes are also unstable, especially those whose atoms have too few neutrons for the number of protons.

Unstable isotopes are short-lived, and often decay by releasing some energy to achieve a more stable configuration. Isotopes in nuclear physics constitute an ongoing area of research, with many isotopes not known to physics.

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

Atoms of the nitrogen-9 isotope are characterised by seven protons and two neutrons – which is an unusually high proton-to-neutron ratio. This disparity has a critical effect on the isotope’s stability, influencing its decay processes as well as overall behaviour.

For one, the high proton content places nitrogen-9 atoms beyond the conventional stability thresholds. That is, if all the atoms lived in a town where their location depended on how stable they were, nitrogen-9 would live outside the town, in a place where no other atom lives.

The question is whether it really exists in this state and, if so, how.