Strange quark polarization of the nucleon: A parameter-independent prediction of the chiral potential model

We perform a one-loop calculation of the strange quark polarization ($\Delta s$) of the nucleon in a SU(3) chiral potential model. We find that if the intermediate excited quark states are summed over in a proper way, i.e., summed up to a given energy instead of given radial and orbital quantum numbers, $\mathrm{\Delta }s$ turns out to be almost independent of {\em all} the model parameters: quark masses, scalar- and vector-potential strengths. The contribution from the quark-antiquark pair creation and annihilation ``$Z$’’ diagrams is found to be significant. Our numerical results agree quite reasonably with experiments and lattice QCD calculations.