Nuclear matter in the chiral limit and the in-medium chiral condensate

We investigate nuclear matter, i.e., the nuclear equation-of-state as well as the relativistic mean fields in the chiral limit. The investigations are based on a chiral nucleon-nucleon EFF interaction where the explicit and implicit pion mass dependence is known up to next-to-leading order. The nuclear bulk properties are found to remain fairly stable in the chiral limit. Based on the same interaction the in-medium scalar condensate is derived, both in Hartree-Fock approximation as well as from the Brueckner G-matrix, making thereby use of the Hellman-Feynman theorem. Short distance physics which determines the reduction of the in-medium nucleon mass is found to play only a minor role for the reduction of the chiral condensate. (c) 2007 Published by Elsevier B.V.