The Second Generation HAPPEx Experiments

The HAPPEx-II experiment at Thomas Jefferson National Accelerator Facility measures the parity-violating helicity-correlated scattering asymmetry APV in elastic electron scattering from 1H and 4He. These measurements explore the strange quark contributions to the electric and magnetic vector form factors GEs and GMs of the nucleon. An introduction to the experimental technique and preliminary results from an initial run of these experiments in summer 2004 are presented.