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

BILENKY M, KNEUR JL, RENARD FM, Schildknecht D. TRILINEAR COUPLINGS AMONG THE ELECTROWEAK VECTOR BOSONS AND THEIR DETERMINATION AT LEP2. NUCLEAR PHYSICS B. 1993;409(1):22-68.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