Strangeness in the nucleon: Newest results from Happex and G0

We present an introduction to accurate measurements of the weak neutral current in the elastic scattering of longitudinally polarized electrons off hadronic targets, and show how they can provide new and stringent limits on the contribution of strange quarks to the nucleon form factors. Such a contribution is of particular interest for the study of nucleon structure, since strange quarks do not contribute to the valence state and give us a direct insight into the dynamics of quark–antiquark fluctuations. We discuss the latest published results of Happex and G0 experiments as well as the perspectives of high precision measurements of parity violating asymmetries.