Z. Kohley, A. Spyrou, E. Lunderberg, P. A. DeYoung, H. Attanayake, T. Bauman, D. Bazin, B. A. Brown, G. Christian, D. Divaratne, S. M. Grimes, A. Haagsma, J. E. Finck, N. Frank, B. Luther, S. Mosby, T. Nagi, G. F. Peaslee, W. A. Peters, A. Schiller, J. K. Smith, J. Snyder, M. J. Strongman, M. Thoennessen, A. Volya
The two-neutron unbound ground state resonances of $^{26}$O and $^{16}$Be were populated using one-proton knockout reactions from $^{27}$F and $^{17}$B beams. A coincidence measurement of 3-body system (fragment + n + n) allowed for the decay energy of the unbound nuclei to be reconstructed. A low energy resonance, $<$ 200 keV, was observed for the first time in the $^{24}$O + n + n system and assigned to the ground state of $^{26}$O. The $^{16}$Be ground state resonance was observed at 1.35 MeV. The 3-body correlations of the $^{14}$Be + n + n system were compared to simulations of a phase-space, sequential, and dineutron decay. The strong correlations in the n-n system from the experimental data could only be reproduced by the dineutron decay simulation providing the first evidence for a dineutron-like decay.
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http://arxiv.org/abs/1208.2969
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