This week, researchers from the Tokyo Institute of Technology have delved into the investigation of tetraneutron emission, a phenomenon that has long been debated within the scientific community. Tetraneutron, an elusive atomic nucleus consisting of four neutrons, has sparked curiosity due to our limited understanding of systems composed solely of neutrons, as most atomic nuclei are typically a combination of protons and neutrons.

Recent experimental studies have reported the presence of tetraneutrons in both bound and resonant states. However, theoretical studies have suggested that tetraneutrons may not exist in a bound state if governed by our conventional understanding of nuclear forces.

Associate Professor Hiroyuki Fujioka and a team of researchers from the Tokyo Institute of Technology sought to explore the feasibility of bound tetraneutron emission. Their study, published in Physical Review C, focused on the potential emission rate of particle-stable tetraneutrons through thermal neutron-induced fission of 235U (Uranium-235) in a nuclear reactor.

Dr. Fujioka explained, ‘We chose to investigate the possibility of bound tetraneutron emission through the 0.2% probability of ternary fission, which involves the emission of light nuclear fragments. This approach was based on the assumption that the hypothetically bound tetraneutron could be a ternary particle in uranium fission.’

The research employed the instrumental neutron activation analysis method, utilizing 88SrCO3 as the target sample, which was irradiated and activated by the capture of thermal neutrons.

This study holds significant implications for the understanding of atomic nuclei and the potential existence of charge-neutral multineutron systems. The exploration of tetraneutrons could offer insights into new properties of atomic nuclei, shedding light on an age-old question in the scientific community.