TY - JOUR
T1 - Chiral dynamics and nuclear matter
AU - Kaiser, N.
AU - Fritsch, S.
AU - Weise, W.
N1 - Funding Information:
✩ Work supported in part by BMBF, GSI and DFG. *Corresponding author. E-mail address: [email protected] (N. Kaiser).
PY - 2002/1/14
Y1 - 2002/1/14
N2 - 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(kf)from one- and two-pion exchange diagrams are ordered in powers of the Fermi momentum kf (modulo functions of kf/mπ). It is demonstrated that, already at order script O sign(kf4), two-pion exchange produces realistic nuclear binding. The underlying saturation mechanism is surprisingly simple (in the chiral limit), namely the combination of an attractive kf 3-term and a repulsive kf4-term. The empirical saturation point and the nuclear compressibility K ≃ 250 MeV are well reproduced at order script O sign(kf5) with a momentum cut-off of Λ ≃ 0.65 GeV which parameterizes short-range dynamics. No further short-distance terms are required in our calculation of nuclear matter. In the same framework we calculate the density-dependent asymmetry energy and find A0 ≃ 34 MeV at the saturation point, in good agreement with the empirical value. The pure neutron matter equation of state is also in fair qualitative agreement with sophisticated many-body calculations and a resummation result of effective field theory, but only for low neutron densities ρn < 0.25 fm-3.
AB - 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(kf)from one- and two-pion exchange diagrams are ordered in powers of the Fermi momentum kf (modulo functions of kf/mπ). It is demonstrated that, already at order script O sign(kf4), two-pion exchange produces realistic nuclear binding. The underlying saturation mechanism is surprisingly simple (in the chiral limit), namely the combination of an attractive kf 3-term and a repulsive kf4-term. The empirical saturation point and the nuclear compressibility K ≃ 250 MeV are well reproduced at order script O sign(kf5) with a momentum cut-off of Λ ≃ 0.65 GeV which parameterizes short-range dynamics. No further short-distance terms are required in our calculation of nuclear matter. In the same framework we calculate the density-dependent asymmetry energy and find A0 ≃ 34 MeV at the saturation point, in good agreement with the empirical value. The pure neutron matter equation of state is also in fair qualitative agreement with sophisticated many-body calculations and a resummation result of effective field theory, but only for low neutron densities ρn < 0.25 fm-3.
KW - Asymmetry energy
KW - Effective field theory at finite density
KW - Neutron matter
KW - Nuclear matter equation of state
UR - http://www.scopus.com/inward/record.url?scp=0000322960&partnerID=8YFLogxK
U2 - 10.1016/S0375-9474(01)01231-3
DO - 10.1016/S0375-9474(01)01231-3
M3 - Article
AN - SCOPUS:0000322960
SN - 0375-9474
VL - 697
SP - 255
EP - 276
JO - Nuclear Physics, Section A
JF - Nuclear Physics, Section A
IS - 1-2
ER -