MadGraph5_aMC@NLO

the NLO QCD cross sections of W+ b b~

Asked by USTCChenNing

hi,

We get a question when trying to evaluate the NLO QCD cross section of the Wpm + b b~ process (Wpm = w+ w-). When we run this process at the LO for the LHC 14 TeV, we got a cross section of ~ 36 pb. However, when we put in the NLO QCD corrections, we got something of ~ 1112 pb. There is a huge difference obviously and we are not sure what is the problem. Would you please help us to clarify the results? thanks a lot.

best,
ning

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

Dear Ning,

In the real-emission corrections to this process, a top pair resonant contribution is opening up. This results in this large enhancement of the cross section. See also the FAQ on the aMC@NLO website for a warning about such processes, http://amcatnlo.web.cern.ch/amcatnlo/list_detailed2.htm#resonances

Best,
Rikkert

Revision history for this message
USTCChenNing (ustc0204-chenning) said : 		#2

Dear Rikkert,

thanks a lot for the link you mentioned.

with regards,
ning

2015-05-04 18:21 GMT+08:00 Rikkert Frederix <
<email address hidden>>:

> Your question #266395 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/266395
>
> Status: Open => Answered
>
> Rikkert Frederix proposed the following answer:
> Dear Ning,
>
> In the real-emission corrections to this process, a top pair resonant
> contribution is opening up. This results in this large enhancement of
> the cross section. See also the FAQ on the aMC@NLO website for a warning
> about such processes,
> http://amcatnlo.web.cern.ch/amcatnlo/list_detailed2.htm#resonances
>
> Best,
> Rikkert
>
> --
> If this answers your question, please go to the following page to let us
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>

--

CHEN, Ning
Department of Modern Physics,
University of Science and Technology of China,
Hefei, Anhui, 230026, China

Revision history for this message
Rikkert Frederix (frederix) said : 		#3

question answered

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