“Exotic Phenomena at the Limits of Nuclear Existence” by Belen Monteagudo, assistant faculty fellow, Physics department

The stability of an atomic nucleus depends on its number of protons Z and neutrons N. With an excess of neutrons, isotopes become unstable and thus very short-lived, with lifetimes that can be as low as several milliseconds. For neutron-rich nuclei very far from stability, the emission of several neutrons becomes the dominant decay mechanism [1] and the formation of multi-neutron systems such as the so-called “tetraneutron" (4n), or larger, is predicted. These systems are very difficult to produce experimentally and yet they are essential to understand the fundamental character of the nuclear interaction. During this talk, we will present results for the spectroscopy and neutron decay of several very neutron-rich isotopes investigated at RIBF-RIKEN using the SAMURAI setup and at NSCL with the MoNA-sweeper setup. In particular, we will focus on the three-body correlations from two-neutron decays (2n) and its characterization from microscopic principles. A joint effort between experiment and theory [2] has allowed a direct comparison to connect the experimental nn signal we observe with the three-body wave-function. We will also present future plans of a next-generation neutron detector that, coupled to the new High Resolution Spectrometer (HRS) at the Facility for Rare Isotope Beams (FRIB), will expand the quest on multi-neutron systems beyond the 2n case. 
 
[1] Y. Kondo et al., Phys. Rev. Lett. 116, 102503  
[2] J. Casal and J. Gómez-Camacho, Phys. Rev. C 99, 014604