Constraining neutron-star matter with microscopic and macroscopic collisions

Wolfgang Trautmann (GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany)

In a recent paper (Huth et al., Nature 606, 276, 2022), the importance of laboratory experiments for determining the properties of neutron-rich supra-nuclear matter was highlighted. This conclusion followed from an analysis combining nuclear theory, nuclear experiment and astrophysical observations within a statistically robust framework using Bayesian inference. It was, in particular, found that the inclusion of heavy-ion collision data indicates an increase in the pressure in dense matter relative to previous analyses, shifting neutron-star radii towards larger values, consistent with recent observations by the Neutron Star Interior Composition Explorer (NICER) mission. Constraints from heavy-ion collision experiments show a remarkable consistency with multi-messenger observations and provide complementary information on nuclear matter at intermediate densities. Data from future experiments in combination with astrophysical observations have thus the potential of advancing our understanding of the nuclear equation of state.