he CM energy range probed, so that the 
parameters of the physics initialization at the nominal energy can be
used as is. Currently it can <b>not</b> be used for the more extensive
energy spread expected at linear <i>e^+ e^-</i> colliders. Also,
any attempt to combine it with external Les Houches input of 
parton-level events is at own risk. 
     
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On this page you can set the momentum spread according to a simple 
Gaussian distribution. If you instead want a more sophisticated 
parametrization, you ca