Date: Wednesday 4-Feb-2015
Time: 1:00 pm
Location: PSC 3150
Speaker: Stefano Gandolfi (Los Alamos National Lab)
Title: The EOS of neutron matter, and the effect of Lambda hyperons to neutron star structure
Recent advances in experiments of the symmetry energy of nuclear matter and in neutron star observations yield important new insights on the equation of state of neutron matter at nuclear densities. In this regime the EOS of neutron matter plays a critical role in determining the mass-radius relationship for neutron stars. We show how microscopic calculations of neutron matter, based on realistic two- and three-nucleon forces, make clear predictions for the relation between the isospin-asymmetry energy of nuclear matter and its density dependence, and the maximum mass and radius for a neutron star. On the other side, several microscopic calculations suggested that the inclusion of hyperons softens the EOS such that the corresponding maximum mass of neutron stars is much lower that astrophysical observations. We will show that very small changes in the nucleon-nucleon-Lambda interactions have a dramatic role to the EOS, while hypernuclei are quite insensitive to the same adjustments.
