Production of single W bosons in e+e- and e-p collisions

The production of W boson in electron-positron colliding beams below the W+ W- threshold is discussed. The corresponding reactions e+ e--> lsup(+-) Wsup(+-) νsup((-))sub(l) yield total cross-sections of the order of 10-37 cm2 (for l=e) and 10-38 cm2 (for l=μ). The total cross-sections as well as the angular and energy distributions of the W boson in e+ e-->esup(+-(ν))sub(e) are sensitive to the magnetic moment of the W. So, with this reaction, not only W bosons can be produced but also the gauge nature of the interaction can be tested. The decay Z0->lsup(+-)Wsup(+-(ν))sub(l) is discussed in view of its observation in e+e- experiments. Finally the cross-sections of e-p->νsub(e)W- X+ are computed. They are of the order of 10-38 cm2 for √sapprox.=200 GeV. (o rig.)