MadGraph5_aMC@NLO

which process can be computed with mg5_amc@nlo

Asked by Gavin Makayla

Hello,

       I an a new learner about next-to-leading order calculation. I really wanna know what kind of processes in SM and new models could be calculated with MG5_aMC@NLO.

       If all the SM processes could be calculated with MG5@NLO, this code sounds like very perfect and easy. Why there still are many papers within only calculating one SM process in arXiv. I am very confused about that.

Cheers,
Gavin

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English Edit question
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Answered
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MadGraph5_aMC@NLO Edit question
Assignee:
Rikkert Frederix Edit question
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Rikkert Frederix (frederix) said : 		#1

Hi Gavin,

In principle any process in the SM can be calculated at NLO accuracy. The only limitations is CPU time. In practice, this means that on a modern desktop any 2->3 process can be calculated at NLO, while on a small computer cluster any 2->4 process can be calculated at NLO.

[There are a couple of exceptions that can be found on the http://amcatnlo.cern.ch website under 'Help and FAQs' there is a section on 'Current limitations and common mistakes'.]

For the moment, we don't have any automation of NLO in BSM physics. (There is some work for Higgs Characterization, see arXiv:1306.6464).

I guess an obvious reason for still using LO predictions is that they are much faster. If the improved accuracy of the NLO corrections are not needed for the analysis, there is not a big gain by including them.

Best regards,
Rikkert

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#2

Hi,

Just to complete the answer of Rik, they are much more progress on BSM than just the Higgs characterization.

>If all the SM processes could be calculated with MG5@NLO, this code sounds like very perfect and easy.
>Why there still are many papers within only calculating one SM process in arXiv. I am very confused about that.

I guess that some journal will start to not publish this kind of paper anymore. At least for the simplest of them.

Cheers,

Olivier

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