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arXiv:1111.1220
SLAC-PUB-14661
IPPP-11-67
DCPT-11-134
LPN11-58
FR-PHENO-2011-019
MCNET-11-24
JHEP 1209 (2012) 049

by: Hoeche, Stefan (SLAC) et al.

Abstract:
In this publication, uncertainties in and differences between the MC@NLO and POWHEG methods for matching next-to-leading order QCD calculations with parton showers are discussed. Implementations of both algorithms within the event generator Sherpa and based on Catani-Seymour subtraction are employed to assess the impact on a representative selection of observables. In the case of MC@NLO a substantial simplification is achieved by using dipole subtraction terms to generate the first emission. A phase space restriction is employed, which allows to vary in a transparent way the amount of non-singular radiative corrections that are exponentiated. Effects on various observables are investigated, using the production of a Higgs boson in gluon fusion, with or without an associated jet, as a benchmark process. The case of H+jet production is presented for the first time in an NLO+PS matched simulation. Uncertainties due to scale choices and non-perturbative effects are explored in the production of W and Z bosons in association with a jet. Corresponding results are compared to data from the Tevatron and LHC experiments.
Link: 
http://inspirehep.net/record/944643
Publ date: 
Saturday, November 5, 2011 - 23:00