New measurement of charge asymmetry $x{F}_3$ from HERA

After presenting the recent measurements of neutral current cross section in DIS at HERA, we explain the effect of the $\gamma -Z_0$ interference at the electro-weak scale, visible on these data. Then, the beam charge difference $x{F}_3$ is measured and the interference itself is extracted. Results are discussed in the context of perturbative QCD.