Helium-6 and Di-neutrons
ABOVE: Some combinations of protons and neutrons are stable and others unstable. New experiments show that helium-6 nuclei consist of a helium-4 core plus two extra loosely-bound neutrons which constitute a "di-neutron," an entity which can actually be transferred to other nuclei in collisions. Other, larger nuclei, such as helium-8 and helium-10 are also possible.
BELOW: The apparatus at the Joint Institute for Nuclear Research in Dubna, Russia, where nuclei in beams of He-6 are He-4 targets exchange di-neutrons. (Courtesy of Yuri Oganessian, JINR)
reported by: Oganessian et al. in the 21 June 1999 issue of Physical Review Letters
