Speeding up MadGraph5_aMC@NLO Mattelaer, O.; Ostrolenk, K.
The European physical journal. C, Particles and fields,
05/2021, Letnik:
81, Številka:
5
Journal Article
Recenzirano
Odprti dostop
In this paper we will describe two new optimisations implemented in
MadGraph5_aMC@NLO
, both of which are designed to speed-up the computation of leading-order processes (for any model). First we ...implement a new method to evaluate the squared matrix element, dubbed helicity recycling, which results in factor of two speed-up. Second, we have modified the multi-channel handling of the phase-space integrator providing tremendous speed-up for VBF-like processes (up to thousands times faster).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A
bstract
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.
We present predictions for the SM-Higgs-pair production channels of relevance at the LHC: gluon–gluon fusion, VBF, and top-pair, W, Z and single-top associated production. All these results are at ...the NLO accuracy in QCD, and matched to parton showers by means of the MC@NLO method; hence, they are fully differential. With the exception of the gluon–gluon fusion process, for which a special treatment is needed in order to improve upon the infinite-top-mass limit, our predictions are obtained in a fully automatic way within the publicly available MadGraph5_aMC@NLO framework. We show that for all channels in general, and for gluon–gluon fusion and top-pair associated production in particular, NLO corrections reduce the theoretical uncertainties, and are needed in order to arrive at reliable predictions for total rates as well as for distributions.
Simulating spin-3/2 particles at colliders Christensen, N.D; de Aquino, P; Deutschmann, N ...
The European physical journal. C, Particles and fields,
10/2013, Letnik:
73, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Support for interactions of spin-3/2 particles is implemented in the FEYNRULES and ALOHA packages and tested with the MADGRAPH 5 and CACLHEP event generators in the context of three phenomenological ...applications. In the first, we implement a spin-3/2 Majorana gravitino field, as in local supersymmetric models, and study gravitino and gluino pair-production. In the second, a spin-3/2 Dirac topquark excitation, inspired from compositeness models, is implemented. We then investigate both top-quark excitation and top-quark pair-production. In the third, a general effective operator for a spin-3/2 Dirac quark excitation is implemented, followed by a calculation of the angular distribution of the s-channel production mechanism.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Simulating spin- $\frac{3}{2}$ particles at colliders Christensen, N. D.; de Aquino, P.; Deutschmann, N. ...
The European physical journal. C, Particles and fields,
10/2013, Letnik:
73, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Simulating spin- particles at colliders Christensen, N. D.; de Aquino, P.; Deutschmann, N. ...
The European physical journal. C, Particles and fields,
10/2013, Letnik:
73, Številka:
10
Journal Article
Recenzirano
Support for interactions of spin-
particles is implemented in the
FeynRules
and
ALOHA
packages and tested with the
MadGraph
5 and
CalcHEP
event generators in the context of three phenomenological ...applications. In the first, we implement a spin-
Majorana gravitino field, as in local supersymmetric models, and study gravitino and gluino pair-production. In the second, a spin-
Dirac top-quark excitation, inspired from compositeness models, is implemented. We then investigate both top-quark excitation and top-quark pair-production. In the third, a general effective operator for a spin-
Dirac quark excitation is implemented, followed by a calculation of the angular distribution of the
s
-channel production mechanism.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Automated tools for the computation of amplitudes and cross sections have become the backbone of phenomenological studies beyond the standard model. We present the latest developments in ...MadDM, a calculator of dark-matter observables based on MadGraph5_aMC@NLO. The new version enables the fully automated computation of loop-induced annihilation processes, relevant for indirect detection of dark matter. Of particular interest is the direct annihilation into photons,
γγ, γX
. These processes lead to monochromatic gamma-ray lines that are smoking-gun signatures for dark-matter annihilation in our Galaxy. MadDM computes the predictions for the expected photon fluxes near Earth and derives constraints from the gamma-ray line searches by Fermi-LAT and HESS. As an application, we present the implications for the parameter space of the Inert Doublet Model.
New Developments in MadGraph/MadEvent Alwall, J; Artoisenet, P; de Visscher, S ...
AIP conference proceedings,
01/2008, Letnik:
1078, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
We here present some recent developments of MadGraph/MadEvent since the latest published version, 4.0. These developments include: Jet matching with Pythia parton showers for both Standard Model and ...Beyond the Standard Model processes, decay chain functionality, decay width calculation and decay simulation, process generation for the Grid, a package for calculation of quarkonium amplitudes, calculation of Matrix Element weights for experimental events, automatic dipole subtraction for next-to-leading order calculations, and a package for automatic calculation of Feynman rules and model files from the Lagrangian of any New Physics model.
This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a ...consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.
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