MadGraph5_aMC@NLO

Generation VBF Higgs to ZZ and its background (qq'->ZZjj)

Asked by Haifeng Li

Dear MG5 experts,

I would like to generate 2 processes with MG5.

1) VBF Higgs, (Higgs->ZZ->l l l l).

I would like to have on-shell Higgs and off-shell Higgs. Is following syntax correct?

generate p p > h > z z j j $$ w+ w- z , z > l+ l-

2) qq->ZZ jj (ZZ->l l l l)

I would like to have this with interference with 1). Is the following syntax correct?

 generate p p > z z j j QCD=0

Cheers
Haifeng

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Olivier Mattelaer
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Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

if you do
> generate p p > z z j j QCD=0, z > l+ l-

you certainly include the Higgs production (on shell and off shell) and the full interference term with the other qed processes.
This does not include any interferences with the QCD background. If you want those then you need to do:
generate p p > z z j j QCD=99 QED=99, z > l+ l-

Cheers,

Olivier

On May 6, 2014, at 12:26 AM, Haifeng Li <email address hidden> wrote:

> New question #248219 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/248219
>
> Dear MG5 experts,
>
> I would like to generate 2 processes with MG5.
>
> 1) VBF Higgs, (Higgs->ZZ->l l l l).
>
> I would like to have on-shell Higgs and off-shell Higgs. Is following syntax correct?
>
> generate p p > h > z z j j $$ w+ w- z , z > l+ l-
>
> 2) qq->ZZ jj (ZZ->l l l l)
>
> I would like to have this with interference with 1). Is the following syntax correct?
>
> generate p p > z z j j QCD=0
>
>
> Cheers
> Haifeng
>
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Haifeng Li (haifengde) said : 		#2

Dear Olivier,

Thanks for the reply. I tried this command using the latest MG5_aMC_v2_1_1.

generate p p > z z j j QCD=99 QED=99

cross section=2.646 pb (everything is default parameter)

That number is quite different with the numbers in the cross section in your latest paper (arxiv :: 1045.0301), table 2 at page 76.

Do you know why?

Cheers
Haifeng

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#3

Hi,

I don’t find any paper with number:
arxiv :: 1045.0301

Cheers,

Olivier
On May 6, 2014, at 1:51 PM, Haifeng Li <email address hidden> wrote:

> Question #248219 on MadGraph5_aMC@NLO changed:
> https://answers.launchpad.net/mg5amcnlo/+question/248219
>
> Status: Answered => Open
>
> Haifeng Li is still having a problem:
> Dear Olivier,
>
> Thanks for the reply. I tried this command using the latest
> MG5_aMC_v2_1_1.
>
> generate p p > z z j j QCD=99 QED=99
>
> cross section=2.646 pb (everything is default parameter)
>
>
> That number is quite different with the numbers in the cross section in your latest paper (arxiv :: 1045.0301), table 2 at page 76.
>
> Do you know why?
>
> Cheers
> Haifeng
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Haifeng Li (haifengde) said : 		#4

Sorry. My type.

http://arxiv-web3.library.cornell.edu/abs/1405.0301

Revision history for this message
Olivier Mattelaer (olivier-mattelaer) said : 		#5

Hi,

As you can see in the paper, we put a cut at 30 GeV for the jet.
The default value that you use in that you use is at 20 GeV.

If I keep all the rest to default and change only the jet cut to 30 then I have:
1.437 ± 0.013
This is not exactly the number of the paper since the PDF set are not the same, the scale choice is not the same,...
But this is clearly close enough.

Cheers,

Olivier

Revision history for this message
Haifeng Li (haifengde) said : 		#6

Dear Olivier,

Thanks for your help. We did include some acknowledgements in our CONF note (page 27th),

https://cds.cern.ch/record/1740973

Cheers
Haifeng

Revision history for this message
Haifeng Li (haifengde) said : 		#7

Thanks Olivier Mattelaer, that solved my question.