The mean free path of protons and neutrons in isospin-asymmetric nuclear matter

We calculate the mean free path of protons and neutrons in symmetric and asymmetric nuclear matter, based on microscopic in-medium nucleon-nucleon cross sections. Those are obtained from calculations of the G-matrix including relativistic "Dirac" effects. The dependence of the mean free path on energy and isospin asymmetry is discussed. We conclude by suggesting possible ways our microscopic predictions may be helpful in conjunction with studies of rare isotopes.Comment: Revised, extended, 9 pages, 4 figure

Triton Binding Energy and Minimal Relativity

For relativistic three-body calculations, essentially two different approaches are in use: field theory and relativistic direct interactions. Results for relativistic corrections of the triton binding energy obtained from the two approaches differ even in their sign, which is rather puzzling. In this paper, we discuss the origin of such discrepancy. We show that the use of an invariant two-body amplitude, as done in the field-theoretic approach, increases the triton binding energy by about 0.30 MeV. This may explain a large part of the discrepancy.Comment: 11 pages, LaTeX, no figure

More on nucleon-nucleon cross sections in symmetric and asymmetric matter

Following a recent work, we present numerical results for total two-nucleon effective cross sections in isospin symmetric and asymmetric matter. The present calculations include the additional effect of Pauli blocking of the final states.Comment: 9 pages, no figures, 5 table

Predicting the single-proton/neutron potentials in asymmetric nuclear matter

We discuss the one-body potentials for protons and neutrons obtained from Dirac-Brueckner-Hartree-Fock calculations of neutron-rich matter, in particular their dependence upon the degree of proton/neutron asymmetry. The closely related symmetry potential is compared with empirical information from the isovector component of the nuclear optical potential.Comment: 9 pages, 6 figures. Minor revisions, added comments, reference

Dirac-Brueckner-Hartree-Fock versus chiral effective field theory

We compare nuclear and neutron matter predictions based on two different ab initio approaches to nuclear forces and the nuclear many-body problem. The first consists of a realistic meson-theoretic nucleon-nucleon potential together with the relativistic counterpart of the Brueckner-Hartree-Fock theory of nuclear matter. The second is based on chiral effective field theory, with density-dependent interactions derived from leading order chiral three-nucleon forces. We find the results to be very close and conclude that both approaches contain important features governing the physics of nuclear and neutron matter.Comment: PDFLATEX, 6 figures. arXiv admin note: substantial text overlap with arXiv:1107.3339, arXiv:1111.0695, arXiv:1002.014

Reduced regulator dependence of neutron-matter predictions with chiral interactions

We calculate the energy per particle in infinite neutron matter perturbatively using chiral N3LO two-body potentials plus N2LO three-body forces. The cutoff dependence of the predictions is investigated by employing chiral interactions with different regulators. We find that the inclusion of three-nucleon forces, which are consistent with the applied two-nucleon interaction, leads to a strongly reduced regulator dependence of the results.Comment: 7 pages, 8 figures, 1 table, to be published in Physical Review