27.12.04

1. MC GENERATORS in ATLAS LCG Generators Russian team meeting 27 Dec.2004 27.12.04 1 MC generators in ATLAS S.Sivoklokov

2. The organisation and dependencies of ATLAS MC code Sets up the containers to hold the events in a collection of HepMC events Contains the base classes Contains the code for HERWIG interface snd the Algorithm to load it 27.12.04 2 MC generators in ATLAS S.Sivoklokov

3. The individual Generators are run from inside Athena (a GAUDI-based OO framework for generation, detector simulation and reconstruction) • Their output is converted into a common format by mapping into HepMC. A container of these is placed into the transient event store (StoreGate in Athena). • The Generator module is activated from the jobOption service theApp.Dlls += [ "Pythia_i" ] theApp.TopAlg = ["Pythia"] • The parameters are passed via jobOption file: Pythia.PythiaCommand = ["pysubs msel 13","pysubs ckin 3 18.","pypars mstp 43 2"] • User can made modification (replace, add routines) building a new generator (interface) library • The External/<Generator> library is used to set up the path to the generator library (which is now pointing to the release maintained by GENSER for some generartors) 27.12.04 3 MC generators in ATLAS S.Sivoklokov

4. Event Generators in Athena Generalpurpose Specialized Decay tools • Mc@NLO2.2 • MacCup • CompHep • AcerMC • Alpgen1.3.1 • TopRex (single top) • PythiaB (use in B physics) • ParticleGenerator • CosmicGenerator • Herwig 6.504 • Pythia 6.226 • Isajet 7.69 • Hijing 1.383 • Sherpa (C++) • Photos • Jimmy • Tauola/Photos • EvtGen • GenzModule (G3 Truth) GENSER 0.3.0 Combinations is possible, i.e. CompHep+Pythia+Tauola (gen,hadronise,decay) See documentation in /doc or http://www-theory.lbl.gov/~ianh/monte/Generators/ 27.12.04 4 MC generators in ATLAS S.Sivoklokov

5. Tools for Generators in Athena Generator Filters: Simple filtering for Leptons, etc Templates for users to add new ones GenAnalysisTools TruthExamples: DumpMC, HistSample,TruthDemo TruthHelper:Predicates for stables, invisibles etc CBNT_Truth CBNT_Truth: MC truth Ntuple CBNT_Spcl: Keeps “important” MC particles 27.12.04 5 MC generators in ATLAS S.Sivoklokov

6. Application Manager StoreGate Svc Converter Converter Converter Event Selector Transient Event Store Message Service Persistency Service Data Files Event Data Service JobOptions Service MC Event Generators Algorithm Algorithm Transient Detector Store Sequencer Particle Prop. Service Persistency Service Data Files Detec. Data Service Other Services Transient Histogram Store Persistency Service Data Files Auditors Histogram Service Scripting Service 27.12.04 6 MC generators in ATLAS S.Sivoklokov

7. Bytestream Raw Digits ESD Mixing Bytestream Raw Digits Reconstruction Digits (RDO) MCTruth Geant4 Digitization Events HepMC Hits MCTruth Bytestream Raw Digits ESD Pythia Digits (RDO) MCTruth Reconstruction Geant4 Digitization Events HepMC Hits MCTruth Geant4 Pile-up Digits (RDO) MCTruth Events HepMC Hits MCTruth Bytestream Raw Digits ESD Bytestream Raw Digits Reconstruction Mixing Geant4 Events HepMC Hits MCTruth Pile-up Digits (RDO) MCTruth Bytestream Raw Digits 18 TB 5 TB 24 TB 75 TB ~2 TB Event Mixing Digitization (Pile-up) Reconstruction Detector Simulation Event generation Byte stream Persistency: Athena-POOL TB Volume of data for 107 events Piled-up events Physics events Min. bias Events Mixed events Mixed events With Pile-up ATLAS Data Challenge-2 CHAIN 27.12.04 7 MC generators in ATLAS S.Sivoklokov

8. CONCLUSION • -The ATLAS Monte-Carlo software is an integral part of the global ATLAS sotware for simulation of all details of experimental setup. • -It is enough flexible to adopt any new MC generator or to use any version of existing generators. • -User has a freedom to change a desirable parameters or to use combinations of different generator modules. 27.12.04 8 MC generators in ATLAS S.Sivoklokov