Nuclear Physics & RIKEN Theory Seminar

We present a phenomenological theory of nuclei which incorporates clustering at the nuclear surface in a general form. The theory explains the recently reported large values of symmetry energy by Natowitz et al at low densities of nuclear matter and is fully consistent with the static properties of nuclei. In phenomenological way clusters of all sizes, shapes along with medium modifications are included. Nuclear matter properties are discussed in detail.
Arguments are given which lead to an equation of state of nuclear matter consistent with clustering. As a framework, an extended version of Thomas Fermi theory is adopted. This connects the nuclear matter equation of state, which incorporate clustering at low densities, with clustering in nuclei at the nuclear surface.
Calculations are performed for various equation of state of nuclear matter consistent with clustering. The importance of quartic term in symmetry energy is demonstrated at and below the saturation density in nuclear matter. It is shown that it is related both to clustering as well as to the contribution of three-nucleon i nteraction to the equation of state of neutron matter. Reasons for these are discussed. Merits of the results with clustering and no-clustering are discussed. Due to clustering the neutron skin thickness in nuclei, fundamental to neutron star studies, is found to reduce significantly. An estimate of the spinodal density of symmetric nuclear matter is given. Theory predicts new situations and regimes to be explored both theoretically and experimentally.