Fraile Prieto, Luis Mariootros, ...2023-06-172023-06-172018-04-120031-900710.1103/PhysRevLett.120.152504https://hdl.handle.net/20.500.14352/12153© 2018 American Physical Society. A. Chbihi, S. Gal´es, J.-P. Ebran, and L. Sobotka are greatly acknowledged for fruitful discussions. This work was supported by the German Federal Ministry for Education and Research (BMBF Project No. 05P15RDFN1), and through the GSI-TU Darmstadt cooperation agreement. C. A. Bertulani acknowledges support by U.S. Department of Energy Grant No. DE-FG02-08ER41533 and U.S. National Science Foundation Grant No. 1415656. Artículo firmado por más de diez autores.The emission of neutron pairs from the neutron-rich N = 12 isotones ¹⁸C and ²⁰O has been studied by high-energy nucleon knockout from ¹⁹N and ²¹O secondary beams, populating unbound states of the two isotones up to 15 MeV above their two-neutron emission thresholds. The analysis of triple fragment-n-n correlations shows that the decay ¹⁹N (-1p)¹⁸C* → ¹⁶C + n + n is clearly dominated by direct pair emission. The two- neutron correlation strength, the largest ever observed, suggests the predominance of a ¹⁴C 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 ²¹O(-1n)²⁰O*→ ¹⁸O + n + n, attributed to its formation through the knockout of a deeply bound neutron that breaks the ¹⁶O core and reduces the number of pairs.engjournal articlehttp://dx.doi.org/10.1103/PhysRevLett.120.152504https://journals.aps.orgopen access539.1InterferometryDecaysStateFísica nuclear2207 Física Atómica y Nuclear