  The neutron skin of atomic nuclei impacts the structure of neutron-rich
nuclei, the equation of state of nucleonic matter, and the size of neutron
stars. Here we predict the neutron skin of selected light- and medium-mass
nuclei using coupled-cluster theory and the auxiliary field diffusion Monte
Carlo method with two- and three-nucleon forces from chiral effective field
theory. We find a linear correlation between the neutron skin and the isospin
asymmetry in agreement with the liquid-drop model and compare with data. We
also extract the linear relationship that describes the difference between
neutron and proton radii of mirror nuclei and quantify the effect of charge
symmetry breaking terms in the nuclear Hamiltonian. Our results for the
mirror-difference charge radii and binding energies per nucleon agree with
existing data.
