PRETTY GOOD SIMULATION

1
PRETTY GOOD SIMULATION

• ERNESTO MIGLIORE
• Università di Torino/INFN
• Disclaimer not a PGS expert

2

• Fortran library (former SHW) by John Conway
  Higgs/SUSY Tevatron RUN II
• http//www.physics.ucdavis.edu/conway/research/so
  ftware/pgs/pgs.html

• native interafce to PYTHIA and ISAJET
• interface to user events through STDHEP
• Note hadrons to be supplied by the user

• c ----gt pgs_next_event
• ...
• c
• c ----gt tauola_scan
• ...
• c
• c ----gt pgs_trigger
• ...
• c
• c ----gt pgs_recon
• ...
• c
• c ----gt pgs_user_analysis
• c ---gt pgs_write_event

? decays polarization
Event loop
Detector Simulation
Output of selected events through STDHEP
interfaces to HBOOK routines
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PROCESSING OF EVENTS

• pgs_trigger
• ---gt pgs_find_tracks make track list
• ---gt pgs_fill_cal calorimeter energy array
• ---gt pgs_find_clusters calorimeter energy
  clusters
• ---gt pgs_find_TTT_trig
• pgs_recon
• ---gt 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

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

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/pT4x10-5 pT (GeV)
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CALORIMETRY

• Hard-coded
• single pion energy
• 100 HAD 50 times
• 25 EM 75 HAD 50 times
• EM cluster definition EHAD/EEMlt12.5

(?0) CDF ATLAS CMS
EM PbSci PbLAr PbWO4
EM 19 X0 24 X0 26 X0
EM 1 ?I 1.2 ?I 1.1 ?I
HAD FeSci FeSci CuSci
HAD 4.5 ?I 7.2 ?I 5 ?I
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b-TAGGING
Track counting (N3)
?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
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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

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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)