Simulation of the baseline RPC trigger system for CMS: Efficiency and Output Rates in Single Muon Topology

This document contains a comprehensive set of results obtained in a simulation study of the performance of the baseline CMS RPC trigger system stand-alone. Single muon trigger efficiency and output rates are reported. The contribution to the output rate from muons produced at the vertex of the apparatus, muons from hadron decays and accidental triggers are considered. The RPC system geometry version implemented in CMSIM 118 has been used. The RPC detector response has been simulated in a realistic way that includes the full timing chain, efficiency, cluster size and intrinsic noise. Streamers have not been simulated. Uncorrelated hits due to thermal neutrons, which are expected to be the main source of physical background in CMS, have been included in the simulation. Having in mind the experimentally measured values of the RPC characteristics, the system proves to be efficient enough, b ut its output rate turns out to be very sensitive to the cluster size and above all the contribution to it due to false triggers caused by the RPC intrinsic noise is unacceptably high in the barrel region.