Δs density in a proton and unpolarized lepton-polarized proton scatterings

It is shown that the parity-violating deep-inelastic scatterings of unpolarized charged leptons on polarized protons, ℓ∓+P→vℓ(−)+X, could provide a sensitive test for the behavior and magnitude of the polarized strange-quark density in a proton. Below charm threshold these processes are also helpful to uniquely determine the magnitude of individual polarized parton distributions.