34
views
0
recommends
+1 Recommend
0 collections
0
shares
• Record: found
• Abstract: found
• Article: found
Is Open Access

# The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations

Preprint

Bookmark
There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

### Abstract

We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5_aMC@NLO, capable of handling all these computations -- parton-level fixed order, shower-matched, merged -- in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV $$e^+e^-$$ collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.

### Most cited references34

• Record: found
• Abstract: found
• Article: found
Is Open Access

### Parton distributions for the LHC

(2009)
We present updated leading-order, next-to-leading order and next-to-next-to-leading order parton distribution functions ("MSTW 2008") determined from global analysis of hard-scattering data within the standard framework of leading-twist fixed-order collinear factorisation in the MSbar scheme. These parton distributions supersede the previously available "MRST" sets and should be used for the first LHC data-taking and for the associated theoretical calculations. New data sets fitted include CCFR/NuTeV dimuon cross sections, which constrain the strange quark and antiquark distributions, and Tevatron Run II data on inclusive jet production, the lepton charge asymmetry from W decays and the Z rapidity distribution. Uncertainties are propagated from the experimental errors on the fitted data points using a new dynamic procedure for each eigenvector of the covariance matrix. We discuss the major changes compared to previous MRST fits, briefly compare to parton distributions obtained by other fitting groups, and give predictions for the W and Z total cross sections at the Tevatron and LHC.
Bookmark
• Record: found

### Reliable Perturbative Results for Strong Interactions?

(1973)
Bookmark
• Record: found

### One-loop corrections for e+e− annihilation into μ+μ− in the Weinberg model

(1979)
Bookmark

### Author and article information

###### Journal
2014-05-01
2014-07-21
1405.0301
10.1007/JHEP07(2014)079

CERN-PH-TH/2014-064, CP3-14-18, LPN14-066, MCNET-14-09, ZU-TH 14/14
JHEP07(2014)079
158 pages, 27 figures; a few references have been added
hep-ph

High energy & Particle physics