Simulation Project Structure and tasks Simulation Project (G.Cosmo) Coordination Geant4 collaboration Geant4 (J.Apostolakis) LHC-oriented development and support of Geant4 toolkit Fluka (A.Ferrari) LHC-oriented development and support of Fluka FLUKA collaboration Garfield (R.Veenhof) Development, support and interfaces Experiments Validation Physics Validation & Simulation Framework (A.Ribon) Validation of the detector simulation MC engines Generator Services (A.Ribon) Event generators repository, generator validation, HepMC MC4LHC LCG Simulation Project

Geant4: Releases, Highlights (1/2) SFT members contribute in physics (validation and modeling), geometry and integration testing. Contributed to releases and patches Releases 9.2 (Dec 2008), 9.2-beta (Jun 08), 9.1 (Dec 07) Patches (3) were provided to release 9.1 during all of 2008 As agreed with users (incl. LHC experiments) Exceptional patches to 8.3 and 9.0, back-porting fixes from 9.1 patch 1 (Feb 2008) Delta Review of Geant4 held 19th-20th Jan 2009 @ CERN Panel included 3 physicists from LHC experiments Major changes in integration testing I. McLaren retired, and G. Folger took over Undertook move to LCG nightly system for testing Geometry: new GDML integrated module for reading and writing EM processes: improved Bremsstrahlung Relativistic corrections; new process for hadrons Review panel membership included: Charles Young (ATLAS, SLAC – chair), Fabio Cossuti (CMS, INFN), Andreas Morsch (ALICE, CERN)

Geant4: Highlights (2/2) Hadronic Physics Improvements Hadronic physics is major focus area Extended validation against further data For energies around 1 GeV, from 5-15 GeV and at 150 GeV Improved FTF Fritiof model (re-tuning) For use in most challenging energy regime: 7-15 GeV Created new physics lists (FTF_BIC, QGS_BIC) Improved agreement in rapidity ‘region’ of target From the re-interaction inside the nucleus of the slow particles created in high-energy part of interaction Problem in matching of energy response remains Reported by CMS, ATLAS. Reproduced in simple setups Ongoing investigation

LCG Generator Services GENSER Structure stable and used by experiments 24 generators installed (most with different versions) Available for testing the first version of Pythia built with autotools First version of a “bootstrap” script to help building GENSER automatically on a laptop Started migration to SLC5 1 new testing package: MC-Tester Started evaluation of Rivet and HepMC Analysis Tool for regression testing based on distributions HepMC New release 2.05.00 in progress, expected in March MCDB Under testing in CMS production LCG Simulation Project

LCG Physics Validation Pion longitudinal shower shapes are ok now; some minor improvements still needed for lateral shapes, and for protons (see LCG note: CERN-LCGAPP-2008-01) Main focus now on energy response and resolution Non-smooth transitions between hadronic models QGSP_BERT is the default Physics List used in ATLAS and CMS. However, there is a growing interest for FTF_BIC and FTFP_BERT Physics Lists, after recent major improvements in the Fritiof model smoother energy response than QGSP_BERT but higher response than QGSP_BERT LCG Simulation Project

LCG Simulation Project X, CMS ECAL+HCAL response: E_vis / E_beam as a function of the beam energy, for pion and proton beams S. Banerjee, LCG Physics Validation meeting, 3-Dec-2008 LCG Simulation Project

Current LCG Simulation manpower As of Jan 2009 Geant4 5.10 (6.90) Infrastructure, performance, management (approx) 2.25 (2.15) Electromagnetic / Hadronic Physics effort (approx) 2.40 (3.30) Geometry, tracking, biasing (approx) 0.45 (1.15) CERN staff (3.00 -> 2.70), CERN fell./assoc./stud. (2.10 -> 3.90) Physics validation & Framework 0.40 (0.80) (**) Validation specific to experiments 0.00 Generator services 2.00 (1.70) management, documentation/release 0.30 (0.00) GENSER dev., Validation, MCDB 1.70 Fluka Garfield (interface library to Geant4) 0.20 Management 0.25 Total   7.95 (9.85) 14.85 in Nov. 2007 ! (x.xx) Manpower as of July 2009 (**) Missing coordination starting from June 2009 ! LCG Simulation Project