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Generators. ATLAS and CMS choices (LHCb, LHCf…); TOTEM strategies. Federico Ceccopieri. Generators. ATLAS : PYTHIA (8.0), (PHOJET), JIMMY+HERWIG … “Modelling Underlying Events and Minimum Bias Physics” J.Butterworth http://indico.cern.ch/conferenceDisplay.py?confId=a042085
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Generators • ATLAS and CMS choices (LHCb, LHCf…); • TOTEM strategies. SW TOTEM Meeting 4/12/07 Federico Ceccopieri
Generators • ATLAS : PYTHIA (8.0), (PHOJET), JIMMY+HERWIG … • “Modelling Underlying Events and Minimum Bias Physics” • J.Butterworth • http://indico.cern.ch/conferenceDisplay.py?confId=a042085 • “Prediction for minimum bias and the underlying event • at LHC energies” . Moraes , C. Buttar , I. Dawson , 2007 Eur.Phys.J.C50:435-466,2007. SW TOTEM Meeting 4/12/07 Federico Ceccopieri
Generators • CMS :PYTHIA, POMWIG, EXHUME … • “Minumum Bias at CDF and CMS” Rick Field • “Pythia settings used in CMS official production”, P.Bartalini • http://indico.cern.ch/conferenceDisplay.py?confId=4081 • “Exhume and Pomwig in CMSSW” A. Vilela Pereira • http://indico.cern.ch/conferenceDisplay.py?confId=17652 SW TOTEM Meeting 4/12/07 Federico Ceccopieri
Generators • No available tuning will be probably “ok” for LHC, due to uncertainties in energy extrapolation of UE and MB in the • MC underlying models. • Use Monte Carlo as error bands : Obs∈ [PHOJET, PYTHIA] • TOTEM : elastic cross-section → total cross-section → unitarity → obtain constraint on multiple interactions; • TOTEM : Test ifleading baryon spectrum is affected by “rescattering”; same spectrum as observed at HERA? • (No help from CDF due to a restricted ξ-range). • Measure all ξ<0.2 not just at the diffractive peak • → test factorization breaking in a wide ξ –range, if any!! SW TOTEM Meeting 4/12/07 Federico Ceccopieri