Narrow Results

Electroweak data from the high energy electron–positron and proton–antiproton colliders are reviewed. On the whole the data is consistent with and supports the predictions of the electroweak theory. However, a crucial prediction of the theory remains to be verified: the existence of the Higgs boson and its light mass, less than 193 GeV, obtained from a fit to all the data within the electroweak framework. The lower limit on its mass from direct searches being 114 GeV, the mass of the Higgs is fixed within a narrow range which is expected to be explored at the Fermilab Tevatron experiments or later at the Large Hadron Collider at CERN.

The anomalous $WW\gamma$ coupling is probed through $e\gamma \to \nu W$ at the ILC. With a spectacular single lepton final state, this process is well suited to study the above coupling. Cross-section measurements can probe $\delta {\kappa }_{\gamma }$ to about $\pm 0.004$ for a luminosity of 100 fb${}^{-1}$ at 500 GeV center-of-mass energy with unpolarized electron beam. The limits derivable on ${\lambda }_{\gamma }$ from the total cross-section are comparatively more relaxed. Exploiting the energy-angle double distribution of the secondary muons, kinematic regions sensitive to these couplings are identified. The derivable limit on ${\lambda }_{\gamma }<0$ could be improved to a few per-mil, focusing on such regions. More importantly, the angular distributions at fixed energy values, and energy distribution at fixed angles present very interesting possibility of distinguishing the case of ${\lambda }_{\gamma }<0$ and ${\lambda }_{\gamma }\ge 0$.