Ni-54 Charge Radius Measured – Neutron Skin and Neutron Stars

The charge radius of radioactive ⁵⁴Ni (28 neutrons and 26 protons) was measured for the first time. This size can be considered as the radius of the neutron distribution of the mirror partner ⁵⁴Fe (26 neutrons and 28 protons), and the difference between their charge radi provides the thickness of its neutron skin. While this is only correct when neglecting the electrostatic repulsion between the protons, it is still possible to extract an important parameter of nuclear matter, called L, from the difference. Interestingly, this value of the neutron skin, when analyzed with the help of theoretical models, yields a parameter L that is consistent with the observational constraints imposed from the gravitational-wave detection of the binary neutron star merger GW170817.
The publication in Physical Review Letters appeared today and is available here. More details of this story can be read in the news of the Michigan State University.