Köln 2004 – scientific programme

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HK: Physik der Hadronen und Kerne

HK 13: Poster Session: Theory

HK 13.3: Poster

Tuesday, March 9, 2004, 13:30–15:30, Foyer

Chiral Dynamics and Nuclear Matter — •Stefan Fritsch¹, Norbert Kaiser¹, and Wolfram Weise^2,1 — ¹Physik Department der Technischen Universität München, Garching, Germany — ²ECT*, Villazzano (Trento), Italy

We calculate the equation of state of isospin-symmetric nuclear matter in the three-loop approximation of chiral perturbation theory. The contributions to the energy per particle Ē(k_f) from one- and two-pion exchange diagrams are ordered in powers of the Fermi-momentum k_f (modulo functions of k_f /m_π). Already at order O(k_f⁴) two-pion exchange produces realistic nuclear binding. Without inclusion of any further short-range terms the empirical saturation point, nuclear compressibility and asymmetry energy are well reproduced at order O(k_f⁵) with a momentum cut-off of Λ≃ 0.65 GeV. We also evaluate the momentum and density dependent single particle potential of nucleons in isospin-symmetric nuclear matter. Furthermore, we extend our scheme to finite temperatures and observe the liquid–gas phase transition of nuclear matter at T_c≃ 25.5 MeV and ρ_c≃ 0.5ρ₀. In addition to that, we investigate the influence of additional explicit short range NN-interaction terms on the momentum dependence of the single particle potential and on the critical temperature of the phase transition. The effects of higher order diagrams with virtual Δ excitations are also considered.

Work supported in part by BMBF, GSI and DFG.