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