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arXiv · hep-lat/9809066

The Pion-Nucleon sigma-Term with Dynamical Wilson Fermions

SESAM-Collaboration·:·S. Güsken·P. Ueberholz·J. Viehoff·N. Eicker·P. Lacock·T. Lippert·K. Schilling·A. Spitz·Th. Struckmann
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Abstract

We calculate connected and disconnected contributions to the flavour singlet scalar density amplitude of the nucleon in a full QCD lattice simulation with $n_f=2$ dynamical Wilson fermions at $β=5.6$ on a $16^3 \times 32$ lattice. We find that both contributions are of similar size at the light quark mass. We arrive at the estimate $σ_{πN} = 18(5)$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 $y=0.59(13)$.}

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SESAM-Collaboration, :, S. Güsken, P. Ueberholz, J. Viehoff, N. Eicker, P. Lacock, T. Lippert, K. Schilling, A. Spitz, Th. Struckmann. 1998-11-23. The Pion-Nucleon sigma-Term with Dynamical Wilson Fermions. https://doi.org/10.1103/physrevd.59.054504

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