  RapidSim is a lightweight application for the fast simulation of phase space
decays of beauty and charm quark hadrons, allowing for quick studies of the
properties of signal and background decays in particle physics analyses. Based
upon the TGenPhaseSpace class from the ROOT application it uses externally
provided fixed-order next-to-leading-logarithm calculations to boost the
initial beauty and charm hadrons to the appropriate energy for the production
environment of interest. User-defined momentum resolution functions can be used
to mimic the effect of imperfect track reconstruction. User-defined efficiency
shapes can be applied during generation to reproduce the effects of geometric
and kinematic requirements on final state particles as well as the dynamics of
the decay. The effect of mis-identification of the final state particles is
simple to configure via configuration files, while the framework can easily be
extended to include additional particle types. This paper describes the
RapidSim framework, features and some example use cases.
