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Nuclear Physics Seminar: From neutron-rich nuclei to stars

Speaker: Sonia Bacca, TRIUMF

Location: Auditorium

Time: 15:30

The neutron distribution in nuclei is a key observable which constrains the size of neutron-rich nuclei as well as the equation of state in nuclear matter and consequently the radii of neutron stars. Measuring the neutron-distribution is difficult. The cleanest way is to use parity violating electron scattering off nuclei, as done in the PREX (on 208Pb) and CREX (on 48Ca) experiments at Jefferson Laboratory, to extract the neutron-skin of nuclei. Other collaborations have focused on measuring complementary observables related to the neutron-distribution, such as the electric dipole polarizability, being studied at RCNP, Japan with inelastic (p,p') scattering. I will present first predictions from ab-initio theory for both the neutron-skin radius and the electric dipole polarizability of 48Ca [1]. Computations are performed within coupled-cluster theory using two- and three-body nuclear forces, rooted into Quantum Chromodynamics via chiral effective field theory. Making use of interesting correlations among observables and using constraints from the accurate experimental measurement of the charge radius of 48Ca, we provide predictions for this nucleus and investigate consequences in the physics of neutron stars. [1] G. Hagen, A. Ekstrom, C. Forseen, G.R. Jansen, W. Nazarewicz, T. Papenbrock, K.A. Wendt, S. Bacca, N. Barena, B. Carlsson, C. Dirischler, K. Hebeler, M. Horth-Jensen, M. Miorelli, G. Orlandini, A. Schwenk, J. Simonis, Nature Physics 3529 (2015). Watch at http://mediasitemob1.mediagroup.ubc.ca/Mediasite/Play/b47267a6ddac4a06a8a9253ee464bb571d