Testing electroweak vector boson self interactions

Abstract

We review anomalous triple electroweak vector boson (TEVB) couplings. The anomalous vertex is written in a model independent way and related to the moments of the W boson. Loop-induced bounds on these couplings are derived, including those obtained from the oblique parametersS, T, U. We show that these bounds from oblique parameters in particular, cannot rule out anomalous couplings even if the oblique parameters are in complete agreement with SM. The importance of testing the TEVB vertex beyond LEPI is thereby demonstrated. We examine direct bounds obtainable from theW-radiative andWγ production at CDF and D0 collaborations. However, all the bounds on TEVB to date are too weak to limit most models. It is pointed out that future colliders will be needed to probe loop level SM corrections to the TEVB vertex, as well as examine extensions beyond the SM. A detailed study of the process\(e^ + e^ - \to \ell ^ + \ell ^{\prime - } v\bar v^\prime \) is carried out with numerical results pressented for the “Next Linear Collider” (NLC) proposed to run at\(\sqrt s = 500GeV\), 1TeV. We find that the TEVB couplings can be studied accurately enough to probe regions close the loop level corrections within the SM, and also allow for a possibility of separating the photon coupling from that of the Z using polarized beams at the NLC.