1. PRS Session, May 12, 2006Filip Moortgat, ETHZ Generator Interface Generator Interface in CMSSW existing/planned interfaces with generators content of the event record AOB/Announcements

2. PRS Session, May 12, 2006Filip Moortgat, ETHZ General purpose generators There are 2 classical “general purpose” event generators for the LHC: PYTHIA  direct interface exists HERWIG  direct interface being implemented

3. PRS Session, May 12, 2006Filip Moortgat, ETHZ What about C++ generators? Two FORTRAN generators are being rewritten in C++ : PYTHIA8  see Torbjorn’s talk next HERWIG++/ThePEG  will present status later They are not yet fully ready for physics, but would be good to have them interfaced already for testing/validation. SHERPA  indirect interface exists (through HepMC ascii file)

4. PRS Session, May 12, 2006Filip Moortgat, ETHZ What about ME/NLO codes? I would like to start off with two prototype implementations of “complex generator chains”, e. g. : MC@NLO + HERWIG ALPGEN + PYTHIA (volunteer needed) Can we interface with the LCG MCDB for the intermediate files? We have to make sure the provenance is not lost! (biggest challenge) Several others should follow (CompHep, MadGraph, …)

5. PRS Session, May 12, 2006Filip Moortgat, ETHZ Ntuple converter There exists a tool to convert CMKIN ntuples to CMSSW rootuples. It is meant: - for comparison and validation - for complex chains which are not yet supported Do not use it for e.g. new PYTHIA sample generation

6. PRS Session, May 12, 2006Filip Moortgat, ETHZ Proposed new structure Proposed new structure of GeneratorInterface in CMSSW: GeneratorInterface / Pythia6Interface Herwig6Interface Pythia8Interface Herwig++Interface HydjetInterface TopRexInterface MC@NLOInterface ALPGENInterface MadGraphInterface CosmicMuonGenerator BeamHaloGenerator … more upon request

7. PRS Session, May 12, 2006Filip Moortgat, ETHZ Proposed new structure (2) Plus: GeneratorInterface / ParticleGuns MCFileReader NtupleConverter 1 (or 2) responsibles per package: development + maintaining wiki page with howto and examples Volunteers please send me an email!

8. PRS Session, May 12, 2006Filip Moortgat, ETHZ Wiki pages Proposal : one central “GeneratorInterface” page which points to individual pages for every generator (reflecting the repository structure) maintained by the responsible of the particular generator interface containing examples of config cards

9. PRS Session, May 12, 2006Filip Moortgat, ETHZ Recipe for the impatient user Demo: to generate PYTHIA Min Bias events with CMSSW: scramv1 project CMSSW CMSSW_0_6_0; cd CMSSW_0_6_0/src; cmscvsroot CMSSW; cvs login; (passwd: 98passwd) cvs co -r CMSSW_0_6_0 IOMC; cd IOMC/GeneratorInterface/test; eval `scramv1 runtime -csh`; cmsRun mcinput.cfg; (or any other cfg file) mcpool.root containing 20 min bias events

10. PRS Session, May 12, 2006Filip Moortgat, ETHZ Example of config file process TEST = { source = PythiaSource { untracked int32 maxEvents = 50 PSet PythiaParameters { vstring parameterSets = { "pythiaMB" } vstring pythiaMB = { 'MSEL=0 ! User defined processes', 'MSUB(11)=1 ! Min bias process', 'MSUB(12)=1 ! Min bias process',... } } module out = PoolOutputModule { untracked string fileName = "mcpool.root" } Example “mcinput.cfg” :

11. PRS Session, May 12, 2006Filip Moortgat, ETHZ Analysis in Full Framework Mode One can access HepMC information in an EDAnalyzer or an EDFilter (see examples in IOMC/GeneratorInterface/) Handle evt; iEvent.getByType(evt); HepMC::GenEvent * myGenEvent = new HepMC::GenEvent(*(evt>GetEvent())); // loop over all particles for ( HepMC::GenEvent::particle_iterator p = myGenEvent->particles_begin(); p != myGenEvent->particles_end(); ++p ) { // select only muons with a pt > 20 GeV if ( abs((*p)->pdg_id()) == 13 && (*p)->momentum().perp() > 20 ) {…} }

12. PRS Session, May 12, 2006Filip Moortgat, ETHZ Analysis in FWLight Mode gSystem->Load("libPhysicsToolsFWLite"); AutoLibraryLoader::enable(); TFile f("mcpool.root"); Events.Draw("PythiaSource.getHepMCData().particles_size()"); TTree* events = (TTree*) (f.Get("Events")); TBranch* MCBranch = events->GetBranch("edmHepMCProduct_PythiaSource__TEST.obj"); edm::HepMCProduct prod; MCBranch->SetAddress(&prod); int nev = events->GetEntries(); for (int ev = 0; ev < nev ; ++ev){ MCBranch->GetEntry(ev); cout << "Number of particles for event " << ev << " = " << prod.getHepMCData().particles_size() << endl; At the root prompt (macro): Thanks to Chris Jones!

13. PRS Session, May 12, 2006Filip Moortgat, ETHZ Analysis in FWLight Mode (2) for ( HepMC::GenEvent::particle_const_iterator p = prod.getHepMCData().particles_begin(); p != prod.getHepMCData().particles_end(); ++p ) { cout momentum().perp() << endl;} } for ( HepMC::GenEvent::vertex_const_iterator v = prod.getHepMCData().vertices_begin(); v != prod.getHepMCData().vertices_end(); ++v ) { cout position().z() << endl;} }...

14. PRS Session, May 12, 2006Filip Moortgat, ETHZ Content of the event record HepMC GenEvent content: particles, vertices, scale, process ID, weights random numbers? add possibility to store cross-section per event? (e.g. PARI(1)) (for sure we need to store it per sample!) add possibility to add extra pdf information in GenEvent? (x1, x2, …) other information? Speak up now!!

15. PRS Session, May 12, 2006Filip Moortgat, ETHZ Other issues last Thursday’s GENSER meeting on “Bug reporting for MC Generators” during LHC data taking, many bug reports expected CMS Policy for all generator problems/bugs: use the CMS Generator Savannah page, or send an email to cms-generator@cern.ch if the bug is confirmed by the generator group, proceed with bug report to the MC authors

16. PRS Session, May 12, 2006Filip Moortgat, ETHZ Other issues (2) Cosmic Muon Generator (Philip Biallass, replacing Volker Drollinger): MC muons do not match real data; new parametrization to be released soon. Particle Data Table: new version released soon

17. PRS Session, May 12, 2006Filip Moortgat, ETHZ Announcements Next week @ CERN: “Flavour in the era of the LHC” workshop http://mlm.home.cern.ch/mlm/FlavLHC.html Monday afternoon discussion on the SUSY Les Houches Accord “Tools for SUSY/BSM” workshop in Annecy, June 26-28. http://lappweb.in2p3.fr/TOOLS2006