Darmstadt 2016 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 67: Nuclear Astrophysics VI

HK 67.6: Talk

Friday, March 18, 2016, 15:30–15:45, S1/01 A02

Equation of state of neutron-rich nuclear matter from chiral effective field theory — Norbert Kaiser and •Susanne Strohmeier — Technische Universität München

Based on chiral effective field theory, the equation of state of neutron-rich nuclear matter is investigated systematically. The contributing diagrams include one- and two-pion exchange together with three-body terms arising from virtual Δ(1232)-isobar excitations. The proper expansion of the energy per particle, Ē(k_f,δ) = Ē_n(k_f) + δ B₁(k_f) +δ^5/3 B_5/3 (k_f) + δ ² B₂ (k_f) + … , for the system with neutron density ρ_n= k_f³ (1−δ)/3 π² and proton density ρ_p= k_f³ δ/3 π² is performed analytically for the various interaction contributions. One observes essential structural differences to the commonly used quadratic approximation. The density dependent coefficient B₁(k_f) turns out to be unrelated to the isospin-asymmetry of nuclear matter. The coefficient B_5/3 (k_f) of the non-analytical δ^5/3-term receives contributions from the proton kinetic energy and from the one- and two-pion exchange interactions. The physical consequences for neutron star matter are studied.