Calculating the muon system response to background long-lived particles in the ATLAS detector at the Large Hadron Collider

An efficient method for constructing the background generator of the muon system for pp collisions in the ATLAS detector (Large Hadron Collider) is presented. The new method allows one to considerably reduce the number of simulations of secondary particles stopping up to thermal energies and to parameterize background particle fluxes. The correct choice of particles from parameterized fluxes allows one to simulate the muon system response in detailed geometry with the necessary statistical accuracy in reasonable time. The proposed method was developed and used to investigate the operation of the ATLAS muon trigger.