1. Physics list update Phone conference 18/2 -04 Rikard Sandström Geneva University

2. Purpose Make sure all relevant particles are simulated. Make sure all relevant processes to these particles are simulated. Optimize performance -> Not simulate particles and processes that does not improve results but still uses computing resources.

3. Done so far (not in CVS yet) Leptons: –Added muon decay. –Added neutrinos (to allow decay). Complete renovation of hadronics: –Simulating p, p, n, pi+, pi- The reason for including anti protons is a crash at runtime if not included. Reported as a bug to Geant4 collaboration, they call it a feature. –All other hadrons can only be transported or decay. –Observation: the looping/stuck particles reported by Steve Kahn are caused by hadronics.

4. Hadronic processes The following processes are simulated for the previously mention hadrons: –Decay –Ionisation –Multiple scattering –Elastic processes –Inelastic processes –Capture –(Low E versions of these processes)

5. Cuts Support added for cuts per G4Region –I suggest this kind of code in the DetectorConstuctor classes: // // Regions // // Individual logical volumes are // registered as "root logical volume" so that all daughter volumes in // these logical volumes are also affected by the corresponding regions. // std::vector logVols; logVols.push_back(fLogicGasVolumeTPG); //contains also HV-plane and GEMs //...add more logical volumes here to the array of logical volumes int size = logVols.size(); for (int i = 0; i < size; i++) { G4Region* aRegion = new G4Region(logVols[i]->GetName()); logVols[i]->SetRegion(aRegion); aRegion->AddRootLogicalVolume(logVols[i]); }

6. Cuts (cont.) This is how I want to use the G4Regions in the Physics list: if (MyDataCards.fetchValueString("TrackerOption") == "TPG") { // This is the sensitive gas region of the TPG and the volumes inside it. G4Region* reg = G4RegionStore::GetInstance()->GetRegion("lGasVolumeTPG"); G4ProductionCuts* cuts = new G4ProductionCuts; cuts->SetProductionCut(0.5*mm); reg->SetProductionCuts(cuts); } Parameters in dataCards should be used for setting the cuts in these special regions (here hard coded). –The cuts can be checked with DumpCutValuesTable();

7. Proposal We set a fairly high defaultCutValue. Detectors that need lower energy simulation defines regions (as in the example), and PhysicsList reads in the special cut values from dataCards. We set switches controlled by dataCards for – All hadronics on/off – General hadronic decay on/off Tests suggests we should remove LElastic and Inelastic for all hadrons, since they are rare (< 0.002 per muon event in DetOnly, no RF background)

8. Next Have only had a brief look on leptons. Will confirm with theory, and fix if necessary. Possibly the process ordering is vital here. Run the tests with cooling channel on. (Still problem with what I think is the reference particle. Yagmur?)