CERN Accelerating science

ATLAS Note
Report number	ATL-PHYS-PUB-2014-021
Title	ATLAS Run 1 Pythia8 tunes
Corporate Author(s)	The ATLAS collaboration
Imprint	02 Nov 2014. - mult. p.
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Free keywords	Pythia8 ; Tune ; MPI ; Shower ; MCGENERATORS
Abstract	We present tunes of the Pythia8 Monte Carlo event generator's parton shower and multiple parton interaction parameters to a range of data observables from ATLAS Run 1. Four new tunes have been constructed, corresponding to the four leading-order parton density functions, CTEQ6L1, MSTW2008LO, NNPDF23LO, and HERAPDF15LO, each simultaneously tuning ten generator parameters. A set of systematic variations is provided for the NNPDF tune, based on the eigentune method. These tunes improve the modeling of observables that can be described by leading-order + parton shower simulation, and are primarily intended for use in situations where next-to-leading-order and/or multileg parton-showered simulations are unavailable or impractical.
Scientific contact person	PMG Conveners, ATLAS (atlas-phys-gener-conveners@cern.ch)