Future linear e+e- colliders aim for extremely high precision measurements.
To achieve this, not only excellent detectors and well controlled machine conditions
are needed, but also the best possible estimate of backgrounds. To avoid that lacking
channels and too low statistics becomes a major source of systematic errors
in data-MC comparisons, all SM channels with the potential to yield at least a few
events under the full lifetime of the projects need to be generated, with statistics
largely exceeding that of the real data. Also machine conditions need to
be accurately taken into account. This includes beam-polarisation, interactions due
to the photons inevitably present in the highly focused beams, and coherent interactions
of whole bunches.
This endeavour has already been partly achieved in preparing design documents for both
the ILC and CLIC: Comprehensive samples of fully simulated and reconstructed events are
available for use.
In this contribution, we present how the generation of physics events at linear colliders
is categorised and organised, and the tools used. Also covered is how different aspects of
machine conditions, different sources of spurious interactions (such as
beam-induced backgrounds) are treated and the tools involved for these aspects.