Abstract
The emission of neutron pairs from the neutron-rich isotones and has been studied by high-energy nucleon knockout from and secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment- correlations shows that the decay is clearly dominated by direct pair emission. The two-neutron correlation strength, the largest ever observed, suggests the predominance of a core surrounded by four valence neutrons arranged in strongly correlated pairs. On the other hand, a significant competition of a sequential branch is found in the decay , attributed to its formation through the knockout of a deeply bound neutron that breaks the core and reduces the number of pairs.
- Received 8 January 2018
- Revised 17 February 2018
DOI:https://doi.org/10.1103/PhysRevLett.120.152504
© 2018 American Physical Society