Isolated Leptons and Missing Transverse Momentum and Measurement of W
Production at HERA (H1+ZEUS)

             H1 and ZEUS Collaborations

The search for events containing isolated leptons (electrons or
muons) and missing transverse momentum produced in ep collisions is
performed with the H1 and ZEUS detectors at HERA in the period
1994-2007. The analysed data sample corresponds to an integrated
luminosity of 0.97 fb^{-1}. The observed event yields are compared to
the prediction from the Standard Model. In general good agreement is
found, where the SM prediction is dominated by W production. The
total and differential cross section of this process is measured in a
common phase space.