On the instanton-induced portion of the nucleon strangeness

We calculate the instanton contribution to the proton strangeness in an MIT bag enriched by the presence of a dilute instanton liquid. The evaluation is based on the expression of the nucleon matrix elements of bilinear stran ge-quark operators in terms of a model valence nucleon state and the intera ctions producing quark-antiquark fluctuations on top of that valence state. Our method combines use of the the evolution operator containing a strange ness source and the Feynman-Hellmann theorem. It enables one to evaluate th e strangeness in different Lorentz channels in essentially the same way. On ly the scalar channel is found to be affected by the interaction induced by the random instanton liquid.