Single-particle potential in a chiral approach to nuclear matter including short-range NN-terms |
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Authors: | S Fritsch N Kaiser |
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Institution: | 1.Physik Department T39, Technische Universit?t München, D-85747 Garching, Germany,DE |
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Abstract: | We extend a recent chiral approach to nuclear matter of Lutz et al.Phys. Lett. B 474, 7 (2000)) by calculating the underlying (complex-valued) single-particle potential U(p, k
f) + iW(p, k
f). The potential for a nucleon at the bottom of the Fermi sea, U(0, k
f0) = - 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, k
f0) = 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 ˉEn(k
n) and the asymmetry energy A(k
f) 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.
Received: 19 December 2002 / Accepted: 11 February 2003 / Published online: 15 April 2003 |
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Keywords: | PACS 12 38 Bx Perturbative calculations – 21 65 +f Nuclear matter |
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