First observation of ${}^{13}$Li ground state

Abstract

The ground state of neutron-rich unbound ${}^{13}$Li was observed for the first time in a one-proton removal reaction from ${}^{14}$Be at a beam energy of 53.6 MeV/u. The ${}^{13}$Li ground state was reconstructed from ${}^{11}$Li and two neutrons giving a resonance energy of 120${}_{-80}^{+60}$ keV. All events involving single and double neutron interactions in the Modular Neutron Array (MoNA) were analyzed, simulated, and fitted self-consistently. The three-body (${}^{11}$Li+$n+n$) correlations within Jacobi coordinates showed strong dineutron characteristics. The decay energy spectrum of the intermediate ${}^{12}$Li system (${}^{11}$Li+$n$) was described with an s-wave scattering length of greater than -4 fm, which is a smaller absolute value than reported in a previous measurement.

Accepted for publication in Phys. Rev. C as a Rapid Communication