Search for events with an isolated lepton and missing transverse momentum 
          and a measurement of W production  at HERA

                 ZEUS Collaboration

A search for events with an isolated high-energy lepton and large missing 
transverse momentum has been performed with the ZEUS detector at HERA 
using a total integrated luminosity of 504 pb-1. The results agree well 
with Standard Model predictions. The cross section for production of 
single W bosons in electron-proton collisions with unpolarised electrons 
is measured to be (0.89+0.25-0.22(stat.)+-0.10(syst.)) pb.