Regular Article - Theoretical Physics
Reducible chiral four-body interactions in nuclear matter
Physik-Department T39, Technische Universität München, D-85747, Garching, Germany
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Accepted: 5 December 2015
Published online: 13 January 2016
The method of unitary transformations generates five classes of leading-order reducible chiral four-nucleon interactions which involve pion exchanges and a spin-spin contact term. Their first-order contributions to the energy per particle of isospin-symmetric nuclear matter and pure neutron matter are evaluated in detail. For most of the closed four-loop diagrams the occurring integrals over four Fermi spheres can be reduced to easily manageable one- or two-parameter integrals. One finds substantial compensations among the different contributions arising from 2-ring and 1-ring diagrams. Altogether, the net attraction generated by the chiral four-nucleon interaction does not exceed values of -1.3 MeV for densities .
© SIF, Springer-Verlag Berlin Heidelberg, 2016