An experiment led by staff from the IGFAE, carried out at the GANIL (Grand Accélérateur National d’Ions Lourds) facility in Caen, France, and published in the journal Physics Letters B, has provided new data on ²²C, an exotic nucleus that is the heaviest isotope of carbon. The analysis, carried out by Juan Lois Fuentes, a PhD student who graduated from IGFAE, was supervised by Beatriz Fernández Domínguez, with the participation of Manuel Caamaño Fresco, both researchers at IGFAE and professors at the USC Faculty of Physics. The work led by the IGFAE, in which the LPC in Caen (France), the University of Surrey (United Kingdom) and GANIL staff also participated, was recently highlighted in the GANIL newsletter, “which is an important recognition of the scientific relevance of the project,” the team points out.
As they explain, “exotic nuclei, such as ²²C, act as ‘extreme laboratories’, revealing how matter behaves under conditions that cannot be reproduced on Earth.” This allows us to study the forces that bind atomic nuclei and discover how the elements of our universe are formed. However, direct exploration of ²²C, through single neutron transfer reactions remains beyond the reach of current facilities. But it is possible to improve our knowledge of this isotope by studying the evolution of the nuclear shell structure in lighter isotopes, such as ¹⁷C. In this way, nuclear models are refined and our understanding of why some exotic nuclei remain bound, develop halos, or disappear completely is deepened.
In this particular work, the N=16 shell gap in carbon isotopes was investigated by examining the structure of ¹⁷C, a lighter cousin of ²²C. Using GANIL’s LISE spectrometer, the team produced excited states of ¹⁷C via the (d,p) neutron transfer reaction, with a deuterium target. Analysis by Juan Lois Fuentes revealed that the N=16 energy gap persists even under conditions of extreme neutron-proton imbalance, challenging current theoretical predictions. The next step is to investigate ²²C using new experimental setups and exquisite theories. Future studies, including those that exploit cutting-edge setups such as active targets, will guide research at next-generation facilities around the world and bring us closer to understanding the fundamental limits of matter.
