Study of gamma gamma Background in e+e- -> W+W- nu nu -> H nu nu Events   at the Tesla e+e- Linear Collider
  The effect of the overlap of gamma gamma -> hadrons to H nu nu events has been studied for the case of the Tesla e+e- linear collider at 350 GeV. It was found that, due to the significant bunch length and the track extrapolation accuracy provided by the Vertex Tracker, the gamma gamma background to physics events can be substantially reduced, with moderate loss in reconstruction efficiency, by a combination of kinematical and vertex topology observables. The remaining background, being confined to very forward hadron production, does not significantly interfere with the event reconstruction. 
Marco Battaglia and Daniel Schulte