Tübingen 2003 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 13: Poster-Sitzung: Theorie
HK 13.14: Poster
Dienstag, 18. März 2003, 13:30–15:30, Foyer
Single-particle potential in a chiral approach to nuclear matter including short range NN-terms — •Norbert Kaiser und Stefan Fritsch — Physik Department T39, Technische Universität München, D-85747 Garching
We extend a recent chiral approach to nuclear matter of Lutz et al. [Phys. Lett. B474 (2000) 7] by calculating the underlying (complex-valued) single-particle potential U(p,kf)+i W(p,kf). The potential for a nucleon at the bottom of the Fermi-sea, U(0,kf0)= − 20.0 MeV, comes out as much too weakly attractive in this approach. Even more seriously, the total single-particle energy does not rise monotonically with the nucleon momentum p, implying a negative effective nucleon mass at the Fermi-surface. Also, the imaginary single-particle potential, W(0,kf0)= 51.1 MeV, is too large. More realistic single-particle properties together with a good nuclear matter equation of state can be obtained if the short range contributions of non-pionic origin are treated in mean-field approximation (i.e. if they are not further iterated with 1π-exchange). We also consider the equation of state of pure neutron matter Ēn(kn) and the asymmetry energy A(kf) in that approach. The downward bending of these quantities above nuclear matter saturation density seems to be a generic feature of perturbative chiral pion-nucleon dynamics.
[1] preprint: nucl-th/0207057 Work supported in part by BMBF, DFG and GSI.