New sets of parameters (“tunes”) for the underlying-event (UE) modelling of the pythia8, pythia6 and herwig++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton–proton ( pppp ) data at s√=7TeVs=7TeV and to UE proton–antiproton ( pp¯¯¯pp¯ ) data from the CDF experiment at lower s√s , are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton–proton collisions at 13 TeVTeV . In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons are presented of the UE tunes to “minimum bias” (MB) events, multijet, and Drell–Yan ( qq¯¯¯→Z/γ∗→qq¯→Z/γ∗→ lepton-antilepton+jets) observables at 7 and 8 TeVTeV , as well as predictions for MB and UE observables at 13 TeVTeV .
Event generator tunes obtained from underlying event and multiparton scattering measurements
Sola, V.;AMAPANE, Nicola Carlo;ARGIRO', Stefano;BELLAN, Riccardo;COSTA, Marco;COVARELLI, Roberto;MIGLIORE, Ernesto;MONACO, Vincenzo;OBERTINO, Maria Margherita;ROMERO, Alessandra;SACCHI, Roberto;SOLANO, Ada Maria;
2016-01-01
Abstract
New sets of parameters (“tunes”) for the underlying-event (UE) modelling of the pythia8, pythia6 and herwig++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton–proton ( pppp ) data at s√=7TeVs=7TeV and to UE proton–antiproton ( pp¯¯¯pp¯ ) data from the CDF experiment at lower s√s , are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton–proton collisions at 13 TeVTeV . In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons are presented of the UE tunes to “minimum bias” (MB) events, multijet, and Drell–Yan ( qq¯¯¯→Z/γ∗→qq¯→Z/γ∗→ lepton-antilepton+jets) observables at 7 and 8 TeVTeV , as well as predictions for MB and UE observables at 13 TeVTeV .| File | Dimensione | Formato | |
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