Parity violating target asymmetry in electron - proton scattering

We analyze the parity-violating (PV) components of the analyzing power A in elastic electron-proton scattering and discuss their sensitivity to the strange quark contributions to the proton weak form factors . We point out that the component of A along the momentum transfer is independent of the electric weak form factor and thus compares favorably with the PV beam asymmetry for a determination of the strangeness magnetic moment. We also show that the transverse component could be used for constraining the strangeness radius. Finally, we argue that a measurement of both components could give experimental information on the strangeness axial charge.