Constraining the radii of neutron stars with terrestrial nuclear laboratory data

Neutron star radii are primarily determined by the pressure of isospin asymmetric matter which is proportional to the slope of the nuclear symmetry energy. Available terrestrial laboratory data on the isospin diffusion in heavy-ion reactions at intermediate energies constrain the slope of the symmetry energy. Using this constraint, we show that the radius (radiation radius) of a 1.4 solar mass (M⊙) neutron star is between 11.5 (14.4) and 13.6 (16.3) km.