26 research outputs found
W+n-jet predictions at NLO matched with a parton shower
The MC@NLO method as implemented in the Sherpa MC generator is presented
using the production of W-bosons in conjunction with up to three jets as an
example. Corresponding results computed at next-to leading order in QCD and
including parton shower corrections are compared to recent experimental data
from the Large Hadron Collider.Comment: 4 pages, 2 figures. To appear in the proceedings of DIS 201
Next-to-leading order matrix elements and truncated showers
An algorithm is presented that combines the ME+PS approach to merge sequences
of tree-level matrix elements into inclusive event samples with the POWHEG
method, which combines exact next-to-leading order matrix elements with parton
showers. The quality of the approach and its implementation in Sherpa are
exemplified by results for e+e- annihilation into hadrons at LEP, for Drell-Yan
lepton-pair production at the Tevatron and for Higgs-boson and W+W- production
at LHC energies.Comment: 5 pages, 8 figures; To appear in the proceedings of Physics at the
LHC 2010, DESY, Hamburg, 7-12 June 201
NLO merging in tt+jets
In this talk the application of the recently introduced methods to merge NLO
calculations of successive jet multiplicities to the production of top pairs in
association with jets will be discussed, in particular a fresh look is taken at
the top quark forward-backward asymmetries. Emphasis will be put on the
achieved theoretical accuracy and the associated perturbative and
non-perturbative error estimates.Comment: 6 pages, 3 figures, proceedings contribution for EPS 2013, Stockholm,
17-24 Jul
Event Generation with Sherpa 2.2
Sherpa is a general-purpose Monte Carlo event generator for the simulation of particle collisions in high-energy collider experiments. We summarize essential features and improvements of the Sherpa 2.2 release series, which is heavily used for event generation in the analysis and interpretation of LHC Run 1 and Run 2 data. We highlight a decade of developments towards ever higher precision in the simulation of particle-collision events
Pushing the precision frontier at the LHC with V+jets
This documents the proceedings from a workshop titled `Illuminating Standard candles at the LHC: V+jets' held at Imperial College London on 25th-26th April 2017. It summarises the numerous contributions to the workshop, from the experimental overview of V+jets measurements at CMS and ATLAS and their role in searching for physics beyond the Standard Model to the status of higher order perturbative calculations to these processes and their inclusion in state of the art Monte Carlo simulations. An executive summary of the ensuing discussions including a list of outcomes and wishlist for future consideration is also presented
Soft Photon Radiation in Particle Decays in SHERPA
In this paper the Yennie-Frautschi-Suura approach is used to simulate real
and virtual QED corrections in particle decays. It makes use of the universal
structure of soft photon corrections to resum the leading logarithmic QED
corrections to all orders, and it allows a systematic correction of this
approximate result to exact fixed order results from perturbation theory. The
approach has been implemented as a Monte Carlo algorithm, which a posteriori
modifies decay matrix elements through the emission of varying numbers of
photons. The corresponding computer code is incorporated into the SHERPA event
generator framework.Comment: 59 pages, 12 figures, 5 tables, published version (typos corrected
Multijet merging for vector boson plus jets production including electroweak corrections
We report on next-to-leading order (NLO) QCD and electroweak (EW) corrections to off-shellvector boson production in association with up to two jets. Fixed-order NLO QCD+EW inclusivepredictions for vector boson plus jet production are known to exhibit huge QCD corrections anda pathological behaviour of the EW corrections. This problem is solved by applying multi-jetmerging with an additional jet at NLO. To this end we employ an approximate method to in-clude NLO EW corrections in the MEPS@NLOmulti-jet merging approach. The simulations areperformed with the SHERPAand MUNICHMonte Carlo frameworks using NLO QCD and EWmatrix elements from OPENLOOP