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Significance Statement
Collisions of protons and neutrons in nuclear matter are discussed from a microscopic standpoint. The dynamics of these collisions is encoded in the scattering e ffective cross section, a crucial ingredient for numerical simulations involving heavy nuclei. The emphasis placed on neutron-rich matter refects the recent and fast-growing interest around neutron-rich nuclei, especially short-lived elements normally not found on earth and which are expected to populate the boundaries of the nuclear chart. The paper also addresses the mean free path of protons and neutrons in nuclear matter, a fundamentally important concept in nuclear physics, whose relevance may extend to areas such as radiobiology.
Journal Reference
The European Physical Journal A, 2014, 50:22. F. Sammarruca.
Physics Department, University of Idaho, 83844-0903, Moscow, ID, USA.
Abstract
After reviewing our microscopic approach to nuclear and neutron-rich matter, we focus on how nucleon-nucleon scattering is impacted by the presence of a dense hadronic medium, with special emphasis on the case where neutron and proton densities are different. We discuss in detail medium and isospin asymmetry effects on the total elastic cross section and the mean free path of a neutron or a proton in isospin-asymmetric nuclear matter. We point out that in-medium cross sections play an important role in heavy-ion simulations aimed at extracting constraints on the symmetry potential. We argue that medium and isospin dependence of microscopic cross sections are the result of a complex balance among various effects, and cannot be simulated with a simple phenomenological model.
