MadGraph5_aMC@NLO

Syntax for producing interference between tZ and WZ+b

Asked by Aaron Webb on 2021-01-25

Dear experts,

I'm trying to measure the interference between tZ and EWK WZ+b by simulating them separately, and then simultaneously, but I'm struggling to define a process that generates both tZ and WZ+b.

I use this line to generate tZ (along with the charges flipped):
generate p p > t b~ j Z $$ W+ W- , (t > w+ b , w+ > l+ vl) , Z > l+ l- QED=6

and this to generate WZ+b:
generate p p > w+ Z b b~ j $$ t t~, w+ > l+ vl, Z > l+ l- QED=6

I assumed this should produce both, but no diagrams with tops are generated:
generate p p > w+ b b~ j Z, w+ > l+ vl, Z > l+ l- QED<=6

I've also tried a more general command, but I get the same issue:
generate p p > l+ l- l+ vl b b~ j QED=6

Is there something wrong with my syntax that explains why madgraph isn't generating any tZ for those last two lines?

Thanks in advance for your help!

Question information

Language:: English Edit question

Status:: Solved

For:: MadGraph5_aMC@NLO Edit question

Assignee:: No assignee Edit question

Solved by:: Aaron Webb

Solved:: 2021-07-15

Last query:: 2021-07-15

Last reply:: 2021-06-18

Link existing bug

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Robert Crook (robertcrook) said on 2021-01-25:

I am having a same problem. https://thebestpaintballgun.info/

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Olivier Mattelaer (olivier-mattelaer) said on 2021-01-26:

Hi,

You are likely looking for the following syntax:
generate p p > w+ b b~ j Z QED<=4 , w+ > l+ vl, Z > l+ l-

The coupling restriction are per block and not for the full process

Cheers,

Olivier

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Aaron Webb (afwebb) said on 2021-02-02:

Hi Olivier,

Thanks for the response. Strangely when I use that syntax I now generate only tZ diagrams, so only QED=4. Is there something else I need to adjust to tell madgraph to generate both QED=4 and QED=2 diagrams?

Thanks,
Aaron

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Olivier Mattelaer (olivier-mattelaer) said on 2021-02-02:

The syntax QED<=4 works fine for me and I have both QED=2 and QED=4 Feynman Diagram displayed for the above syntax

Olivier

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fas asd (safs333) said on 2021-04-11:

I discover the problem isn't due to Mac model. It's miles because I used different Photonflux and pdg2pdf (to study photon-photon interactions in Nucleus-Nucleus collisions) in the new MG v2.8.2. If I use MG v2.7.3, there's no this problem. Just like you can see the example of store here https://frankincensedirect.com/shop/