Production ofW-bosons in high energye + e − ande − p collisions

We study the processe ⁺ e ^?→W+hadrons from theZ ⁰-pole to the threshold region forW-pair production, keeping the widths of theZ ⁰ andW finite. Already slightly below threshold the cross section is strongly depressed. Also the total cross section at theZ ⁰-peak is very small. We present a simple model to account for this. We also give exact results to lowest order for the weak Compton processese ⁺ e ^?→e ⁺ W ^? v _e ande ^? p→pW ^? v _e and compare them with results obtained with the equivalent photon approximation.