Maximum mass and radius of neutron stars, and the nuclear symmetry energy

We calculate the equation of state of neutron matter with realistic two- and three-nucleon interactions using quantum Monte Carlo techniques and illustrate that the short-range three-neutron interaction determines the correlation between neutron matter energy at nuclear saturation density and higher densities relevant to neutron stars. Our model also makes an experimentally testable prediction for the correlation between the nuclear symmetry energy and its density dependence-determined solely by the strength of the short-range terms in the three-neutron force. The same force provides a significant constraint on the maximum mass and radius of neutron stars.