Simulations of R-parity Violating SUSY Models

In recent years there has been a great deal of interest in R-parity violating supersymmetric models. We explain the motivation for studying these models and explore the various phenomenological consequences of R-parity violation. In particular, we argue that if we are to explore all channels for the discovery of supersymmetry then these models must be investigated. It has become essential for the experimental study of any new model to have a Monte Carlo event generator which includes the processes predicted by that model. We review the techniques used in the construction of these simulations and show how we have extended the HERWIG event generator to include R-parity violating processes. We discuss how to treat the emission of QCD radiation in these processes including colour coherence effects via the angular-ordered parton shower. We then make use of this simulation to investigate the discovery potential for resonant slepton production, via either supersymmetric gauge or R-parity violating decay modes, in hadron–hadron collisions. In particular, we show that although the colour coherence properties of the R-parity violating decay modes can be used to improve the extraction of a signal above the QCD background these processes will only be visible for large values of the R-parity violating Yukawa couplings. However a signal, i.e. like-sign dilepton production, from the supersymmetric gauge decay modes is visible above the background for much smaller values of the R-parity violating Yukawa couplings. Finally, we look at the possibility that the KARMEN time anomaly can be explained by the existence of a light neutralino which is produced in the decay of charged pions via R-parity violation. This neutralino then decays inside the KARMEN detector, into three leptons via R-parity violation, explaining the excess of events observed by the KARMEN experiment. The road goes ever on and on, down from the door where it began, now far ahead the road has gone and I must follow if I can . . .