# Removing unwanted diagrams

Hello. I would like to get an approximate cross section for p p > W > tau nu H (in the SM) after removing a diagram (specifically, the one in which the H is radiated directly off the W).

I see that there is a way to remove diagrams in https:/

I also see in the results.html file that there is a cross section for each individual graph. Maybe this is just what I need, but I don't understand what the naming convention G1.5 etc. means. Also, this table contains 5 graphs while in the postscript file there are only 2 diagrams. So again, the correspondence b/w the cross sections in the table and the diagrams isn't clear to me.

What should I do?

Thanks,

Abi

## Question information

- Language:
- English Edit question

- Status:
- Answered

- Assignee:
- No assignee Edit question

- Last query:
- 2019-08-14

- Last reply:
- 2019-08-14

HI,

You can also directly edit all the matrix.f files and set the corresponding amplitude to 0.

In your case this sounds simple enough.

Cheers,

Olivier

PS: another method here is to remove such interaction from the UFO model

PPS: If such computation breaks gauge invariance, your result will not be lorentz invariant as well and from there weird stuff can happen.

> On 14 Aug 2019, at 21:47, Abner Soffer <email address hidden> wrote:

>

> New question #682901 on MadGraph5_aMC@NLO:

> https:/

>

> Hello. I would like to get an approximate cross section for p p > W > tau nu H (in the SM) after removing a diagram (specifically, the one in which the H is radiated directly off the W).

>

> I see that there is a way to remove diagrams in https:/

>

> I also see in the results.html file that there is a cross section for each individual graph. Maybe this is just what I need, but I don't understand what the naming convention G1.5 etc. means. Also, this table contains 5 graphs while in the postscript file there are only 2 diagrams. So again, the correspondence b/w the cross sections in the table and the diagrams isn't clear to me.

>

> What should I do?

>

> Thanks,

> Abi

>

>

> --

> You received this question notification because you are an answer

> contact for MadGraph5_aMC@NLO.

## Can you help with this problem?

Provide an answer of your own, or ask Abner Soffer for more information if necessary.