https://doi.org/10.1140/epja/i2006-10159-8
Regular Article - Hadron Physics
Scales in nuclear matter: Chiral dynamics with pion nucleon form factors⋆
Physik Department, Technische Universität München, D-85747, Garching, Germany
* e-mail: nkaiser@ph.tum.de
Received:
16
October
2006
Accepted:
11
December
2006
Published online:
16
January
2007
A systematic calculation of nuclear matter is performed which includes the long-range correlations between nucleons arising from one- and two-pion exchange. Three-body effects from 2π exchange with excitations of virtual Δ(1232)-isobars are also taken into account in our diagrammatic calculation of the energy per particle ¯(k f). In order to eliminate possible high-momentum components from the interactions we introduce at each pion-baryon vertex a form factor of monopole type. The empirical nuclear matter saturation point, ρ0 ≃ 0.16fm^-3, ¯0 ≃ - 16MeV, is well reproduced with a monopole mass of Λ ≃ 4πf π ≃ 1.16GeV. As in the recent approach based on the universal low-momentum NN potential V low-k, the inclusion of three-body effects is crucial in order to achieve saturation of nuclear matter. We demonstrate that the dependence of the pion exchange contributions to ¯(k f) on the “resolution” scale Λ can be compensated over a wide range of Λ by counterterms with two “running” contact couplings. As a further application we study the in-medium chiral condensate 〈¯q〉(ρ) beyond the linear density approximation. For ρ ⩽ 1.5ρ0 we find small corrections from the derivative d¯(k f)/dm π, which are stable against variations of the monopole regulator mass Λ.
PACS: 12.38.Bx Perturbative calculations – / 21.65.+f Nuclear matter –
© Società Italiana di Fisica and Springer-Verlag, 2007