Energy spectrum of leptons from e+e− → W+W− in the presence of strong WL+WL− interaction

The energy spectrum of leptons, produced by the decay of one or both Wʹs in the reaction e+e− → W+W−, is a significant probe of the helicity structure of this process. We calculate the energy spectrum dσdE of a single decay lepton, as well as the two-dimensional energy distribution dσdE+dE−. We then consider a possible strong final state interaction in the longitudinally polarized state of the W+W− system, parametrized by a ϱ-like resonance in the region of 1.8 TeV. We show that such a resonance produces measureble effects in the lepton spectrum at s=500 GeV. The results are compared with those obtained from a non-resonant interaction approximated by a phase factor eiδ in the l = 1 part of the WL+WL− amplitude.