P RETTY G OOD S IMULATION

1. PRETTY GOOD SIMULATION ERNESTO MIGLIORE* Università di Torino/INFN *Disclaimer: not a PGS expert Ernesto Migliore MCWS Frascati 28 Feb 06

2. Fortran library (former SHW) by John Conway Higgs/SUSY Tevatron RUN II http://www.physics.ucdavis.edu/~conway/research/software/pgs/pgs.html • “native” interafce to PYTHIA and ISAJET • interface to user events through STDHEP • Note: hadrons to be supplied by the user c |----> pgs_next_event ... c | c |----> tauola_scan ... c | c |----> pgs_trigger ... c | c |----> pgs_recon ... c | c |----> pgs_user_analysis c |---> pgs_write_event  decays + polarization Event loop Detector Simulation Output of selected events through STDHEP + interfaces to HBOOK routines Ernesto Migliore MCWS Frascati 28 Feb 06

3. PROCESSING OF EVENTS pgs_trigger | |---> pgs_find_tracks make track list |---> pgs_fill_cal calorimeter energy array |---> pgs_find_clusters calorimeter energy clusters |---> pgs_find_TTT_trig pgs_recon |---> pgs_find_RRR • From ISTHEP and PHEP • Smearing of pT, EEM and EHAD Fixed size cone R TTT = /e, , , jet, MET RRR = /e, , , jet, b, c • Analysis of reconstructed objects on events selected on the basis of trigger objects Ernesto Migliore MCWS Frascati 28 Feb 06

4. SIMULATION OF THE DETECTOR • main detector effects: • pT smearing • EEM, EHAD smearing • Energy deposited in towers (granularity of HCAL) • Tag efficiency (-ID, -tagging, b/c-tagging) • Detector parameters partly from cards partly hard-coded Ernesto Migliore MCWS Frascati 28 Feb 06

5. LHC_DETECTOR_PARAMETERS LHC ! parameter set name 81 ! eta cells in calorimeter 63 ! phi cells in calorimeter 0.1 ! eta width of calorimeter cells 0.099733101 ! phi width of calorimeter cells 0.1 ! electromagnetic calorimeter resolution * sqrt(E) 0.8 ! hadronic calorimeter resolution * sqrt(E) 0.2 ! MET resolution 0.00 ! calorimeter cell edge crack fraction 3.0 ! calorimeter cluster finding seed threshold (GeV) 0.5 ! calorimeter cluster finding shoulder threshold (GeV) 0.70 ! calorimeter cluster finder cone size (delta R) 1.0 ! outer radius of tracker (m) 2.0 ! magnetic field (T) 0.000005 ! sagitta resolution (m) 0.98 ! track finding efficiency 0.30 ! minimum track pt (GeV/c) 2.0 ! tracking eta coverage CalorimeterHCAL 5 m pT/pT=4x10-5 pT (GeV) Ernesto Migliore MCWS Frascati 28 Feb 06

6. CALORIMETRY “Hard-coded” • single pion energy • 100% HAD 50% times • 25% EM + 75% HAD 50% times • EM cluster definition: EHAD/EEM<12.5% Ernesto Migliore MCWS Frascati 28 Feb 06

7. b-TAGGING Track counting (N=3) q=# jet q tagged as b /# jets q “Hard-coded” CMS PGS LHCO =0 v3.3 C.Weiser FNAL 18Jan06 uds gluons c eff(b)=50% Ernesto Migliore MCWS Frascati 28 Feb 06

8. SIMULATION OF THE DETECTOR • main detector effects: • pT smearing • EEM, EHAD smearing • Energy deposited in towers (granularity of HCAL) • Tag efficiency (-ID, -tagging, b/c-tagging) • Detector parameters partly from cards partly hard-coded • Not included: • B deflection of charged tracks (effects on the jet broadness) • pile-up (relevant for high luminosity analyses) • underlying event (depending on the MC) • background processes Ernesto Migliore MCWS Frascati 28 Feb 06

9. OUTLOOK/DISCUSSION • PGS validation/tuning • vs. ATLAS and CMS “fast” simulation? • vs. ATLAS and CMS “full” simulation? • atlas.par, cms.par, lhcdet.par? • Which observable in which process (which MC)? • m(ℓℓ) in Z (+jets) • MET in W (+jets) or tt • (isolated ) • Size of the cross-section you want to investigate (nb/pb/fb) Ernesto Migliore MCWS Frascati 28 Feb 06