Checking energy, momentum, … conservation in Hadronics Gunter Folger CERN/PH/SFT

Overview Optional check ◦ Check and inform Mandatory Check ◦ Protect against “catastrophic” non- conservation 4/27/20112

Introduction Implemented in G4HadronicProcess ◦ Common to all processes and models using hadronic framework  Elastic process is moving there 4/27/20113

Optional check Optionally checks and reports  Numbers are (initial – final) state ◦ Energy ◦ Momentum ◦ Charge ◦ Baryon number For developer and testing ◦ Needs environment variable to activate ◦ Needs to set limits in model or process 4/27/20114 new

Optional checking – setup (1) Need to set environment variable G4Hadronic_epReportLevel ◦ 0: off (default) ◦ 1: report when E/p not conserved ◦ 2: always report ◦ 3: report when E/p not conserved,  include process, model, and initial state info for primary and target nucleus ◦ 4: always report,  include process, model, and initial state info for primary and target nucleus ◦ Negative numbers: send report to stderr Need to set limits for non-conservation in model or process 4/27/20115

Optional checking – setup (2) Need to set environment variable G4Hadronic_epReportLevel Need to set limits for non-conservation in model or process ◦ SetEnergyMomentumCheckLevels( 1*perCent, 1*MeV); User can define global via environment variables  G4Hadronic_epCheckRelativeLevel  G4Hadronic_epCheckAbsoluteLevel ◦ These override internal limits 4/27/ newold

Processes/models limits Processes/models limits Assembly like FTFP, only limit set by high energy model is taken String models ◦ QGS: (2%, 150 MeV) ◦ FTF: no limit set! Cascades ◦ Bertini: (5%, 10MeV) ◦ Binary Cascade: (1%, 1 MeV) 4/27/20117

Current status -1 After several fixes to energy non- conservation QGS + Preco ◦ Failures for momentum check ◦ Test12, test13 QGS + Binary (QGSB) ◦ Some failures for charge/baryon FTF + … ◦ ??? 4/27/20118

Current Status - 2 Bertini ◦ None seen Binary Cascade ◦ None seen 4/27/20119

Mandatory check Check energy conservation ◦ Default limit: (10%, 5GeV) ◦ Model may provide different limit ◦ If check fails,  Raise G4Exception “JustWarning” to give details  resample interaction ◦ Or, when G4Hadronic_epReportLevel < 0 (check mode)  Raise G4Exception “EventMustBeAborted” to give details  resample interaction 4/27/201110

Mandatory check (2) Limit may be changed by model GetFatalEnergyCheckLevels() ◦ Models not adding nucleus to final state ◦ (5 %, 250GeV)  LEP, HEP  LCapture, LFission  LElastic  NeutronHPFission 4/27/201111

Results All examples test pass Some problems seen in “check mode” ◦ NeutronHPInelastic  Radioactive decay example ◦ IonInelastic/CascadeModel for He5, fatal  Test62, also error on He5 ◦ FTFB, for light nuclei - Be 4/27/201112

Summary Expect to find problems with enhanced tests ◦ for new quantities ◦ or models Need fixes and improvements ◦ Often model is ok, but combination of two is not, e.g.  QGSP – QGS + GeneratorPrecompoundInterface  FTFB – FTF + Binary Propagate() 4/27/201113