Strong final state interactions in γγ→WW

Abstract We study the effects of a possible strong final state interaction among longitudinal W 's in γγ → WW . The relevant partial wave amplitudes are modified by an Omnes function approximated by a Breit–Wigner form factor. We study the fractional cross section f 00 = σ LL / σ tot with both W 's longitudinally polarised, in the presence of a J =2 resonance ( M =2.5 TeV, Γ =500 GeV) or a J =0 resonance ( M =1 TeV, Γ =1 TeV), whose parameters are scaled up from the f 2 and σ resonances in the ππ system. We also examine the effects of final state interaction in the case of polarised photons ( J z =0 or J z =2), and the impact on the Drell–Hearn–Gerasimov sum rule.