TY  - JOUR
AU  - Güsken, S.
AU  - Ueberholz, P.
AU  - Viehoff, J.
AU  - Eicker, N.
AU  - Lacock, P.
AU  - Lippert, T.
AU  - Schilling, K.
AU  - Spitz, A.
AU  - Struckmann, T.
TI  - Pion-nucleon σ term with dynamical Wilson fermions
JO  - Physical review / D
VL  - 59
IS  - 5
SN  - 0556-2821
CY  - Melville, NY
PB  - Inst.812068
M1  - FZJ-2019-01091
SP  - 054504
PY  - 1999
AB  - 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).
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1103/PhysRevD.59.054504
UR  - https://juser.fz-juelich.de/record/860316
ER  -