TRILINEAR COUPLINGS AMONG THE ELECTROWEAK VECTOR BOSONS AND THEIR DETERMINATION AT LEP2

We present a detailed investigation of the potential of LEP2 to measure the (trilinear) couplings of the vector bosons, Z0W+ W- and gammaW+ W-, among one another. The restrictions imposed on non-standard trilinear couplings by symmetry requirements, thus excluding violent boson-loop divergences and a violent growth of tree amplitudes for vector-boson scattering, are discussed in detail. We elaborate on how to extract the W+/- spin-density matrix and the W+, W- spin correlations from future data. Various theoretically motivated fits to artificial ''data'' on e+ e- --> W+W- are carried out in order to evaluate the potential of LEP2 for, the measurement of trilinear vector boson couplings. We stress that a direct measurement of the couplings of the vector bosons with one another is indispensable for a verification of the basic SU(2)L X U(1)Y structure of the present electroweak theory. Such measurements at LEP2 improve indirect LEP1 bounds by factors which occasionally reach a full order of magnitude.