Validation of Physics Models of Geant4 Versions 10.4.p03, 10.6.p02 and 10.7.p01 using Data from the CMS Experiment

Sunanda Banerjee,Vladimir Ivanchenko,C Biscarat,S Campana,B Hegner,C.I Rovelli,G.A Stewart,S Roiser

doi:10.1051/epjconf/202125103010

Abstract

CMS tuned its simulation program and chose a specific physics model of Geant4 by comparing the simulation results with dedicated test beam experiments. Test beam data provide measurements of energy response of the calorimeter as well as resolution for well identified charged hadrons over a large energy region. CMS continues to validate the physics models using the test beam data as well as collision data from the Large Hadron Collider. Isolated charged particles are measured simultaneously in the tracker as well as in the calorimeters. These events are selected using dedicated triggers and are used to measure the response in the calorimeter. Different versions of Geant4 (10.2.p02, 10.4.p03, 10.6.p02) have been used by CMS for its Monte Carlo production and a new version (10.7.p01) is now chosen for future productions. A suitable physics list (collection of physics models) is chosen by optimizing performance against accuracy. A detailed comparison between data and Geant4 predictions is presented in this paper.

Highlights

The CMS experiment [1] at the Large Hadron Collider uses the Geant4 toolkit [2,3,4]
CMS switched to the Geant4 version 10.2.p02 for its 2017 Monte Carlo (MC) production
CMS is getting ready for the MC production for LHC Run 3 which is scheduled to start in 2022 and chose to use the Geant4 version 10.7.p01

Summary

Introduction

The CMS experiment [1] at the Large Hadron Collider uses the Geant toolkit [2,3,4]. The simulation software as well as the Geant code is evolving since the CMS simulation code has been put into operation. CMS switched to the Geant version 10.2.p02 for its 2017 Monte Carlo (MC) production. CMS is getting ready for the MC production for LHC Run 3 which is scheduled to start in 2022 and chose to use the Geant version 10.7.p01. There has been an active effort within CMS to evaluate the quality of simulation as one changes either the application software or the version of Geant. Results from this test beam have been published [8] and were used in earlier tuning of the CMS simulation program [9,10]. Similar analysis was done earlier in CMS [11] These validation results consolidate the recent adaptation of the new Geant versions and the physics list used for Monte Carlo production

CMS Simulation Software

Validation versus test beam data

Validation versus Run 2 data

Summary