%0 Journal Article
%A Güsken, S.
%A Ueberholz, P.
%A Viehoff, J.
%A Eicker, N.
%A Lacock, P.
%A Lippert, T.
%A Schilling, K.
%A Spitz, A.
%A Struckmann, T.
%T Pion-nucleon σ term with dynamical Wilson fermions
%J Physical review / D
%V 59
%N 5
%@ 0556-2821
%C Melville, NY
%I Inst.812068
%M FZJ-2019-01091
%P 054504
%D 1999
%X We calculate connected and disconnected contributions to the flavor singlet scalar density amplitude of the nucleon in a full QCD lattice simulation with nf=2 dynamical Wilson fermions at β=5.6 on a 163×32 lattice. We find that both contributions are of similar size at the light quark mass. We arrive at the estimate σπN=18(5)MeV. Its smallness is directly related to the apparent decrease of u, d quark masses when unquenching QCD lattice simulations. The y parameter can be estimated from a semi-quenched analysis, in which there are no strange quarks in the sea, the result being y=0.59(13).
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1103/PhysRevD.59.054504
%U https://juser.fz-juelich.de/record/860316