# Cross section

Hi,
Actually, i'm a little confused during calculation of the cross section using MadGraph5, i calcule the sigma(p p > h++ h-- ) i get 0.1761fb but when i calcule the xs with decay of double charged Higgs i get sigma(p p > h++ h-- > l+l+l-l- )= 2866000 fb also all of that using MadGraph5, this last xs what make me confused, my question is that possible?

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 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-08-27: #1

The most likely reason is that you did not set the width of the particles to their LO value.
Note that we have a FAQ on this type of disagreement.

Otherwise, this might also be due to the presence of additional diagram/...

Cheers,

Olivier

 Revision history for this message said ghourmin (saidghourmin) said on 2021-08-27: #2

Do you mean that i don't set the widths of h++ > l+l+ in my code where(l=e
mu tau), and i don't understand what you mean by additional diagram,
because when i have added the lepton final stage other diagram are added

Le ven. 27 août 2021 à 21:01, Olivier Mattelaer <
<email address hidden>> a écrit :

>
>
> Olivier Mattelaer proposed the following answer:
> The most likely reason is that you did not set the width of the particles
> to their LO value.
> Note that we have a FAQ on this type of disagreement.
>
> Otherwise, this might also be due to the presence of additional
> diagram/...
>
> Cheers,
>
> Olivier
>
> --
> know that it is solved:
>
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
>
>

 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-08-27: #3

Hi,

I mean that in the param_card you have to provide the value of the total width for all particle and that all those total width need to be consistent.
We do not use branching ratio so we do not need the partial width information. (even if you need to compute those in order to have the total width).

For the diagram, you have to look at the diagram generated, I do not know your model so i have no clue if this happens in your case or not.

Cheers,

olivier

> On 27 Aug 2021, at 22:15, said ghourmin <email address hidden> wrote:
>
> Question #698539 on MadGraph5_aMC@NLO changed:
>
>
> said ghourmin is still having a problem:
> Do you mean that i don't set the widths of h++ > l+l+ in my code where(l=e
> mu tau), and i don't understand what you mean by additional diagram,
> because when i have added the lepton final stage other diagram are added
>
> Le ven. 27 août 2021 à 21:01, Olivier Mattelaer <
> <email address hidden>> a écrit :
>
>>
>>
>> Olivier Mattelaer proposed the following answer:
>> The most likely reason is that you did not set the width of the particles
>> to their LO value.
>> Note that we have a FAQ on this type of disagreement.
>>
>> Otherwise, this might also be due to the presence of additional
>> diagram/...
>>
>> Cheers,
>>
>> Olivier
>>
>> --
>> know that it is solved:
>>
>>
>> If you still need help, you can reply to this email or go to the
>> following page to enter your feedback:
>>
>>
>
> --

 Revision history for this message said ghourmin (saidghourmin) said on 2021-08-27: #4

My model is 123 model, tomorrow i will attach my code and have a look if
you are available if not intel monday, cuz now i let my machine in
university

Le ven. 27 août 2021 à 21:30, Olivier Mattelaer <
<email address hidden>> a écrit :

>
>
> Olivier Mattelaer proposed the following answer:
> Hi,
>
> I mean that in the param_card you have to provide the value of the total
> width for all particle and that all those total width need to be consistent.
> We do not use branching ratio so we do not need the partial width
> information. (even if you need to compute those in order to have the total
> width).
>
> For the diagram, you have to look at the diagram generated, I do not
> know your model so i have no clue if this happens in your case or not.
>
> Cheers,
>
> olivier
>
> > On 27 Aug 2021, at 22:15, said ghourmin <
> >
> > Question #698539 on MadGraph5_aMC@NLO changed:
> >
> > Status: Answered => Open
> >
> > said ghourmin is still having a problem:
> > Do you mean that i don't set the widths of h++ > l+l+ in my code
> where(l=e
> > mu tau), and i don't understand what you mean by additional diagram,
> > because when i have added the lepton final stage other diagram are added
> >
> > Le ven. 27 août 2021 à 21:01, Olivier Mattelaer <
> > <email address hidden>> a écrit :
> >
> >>
> >> Status: Open => Answered
> >>
> >> Olivier Mattelaer proposed the following answer:
> >> The most likely reason is that you did not set the width of the
> particles
> >> to their LO value.
> >> Note that we have a FAQ on this type of disagreement.
> >>
> >> Otherwise, this might also be due to the presence of additional
> >> diagram/...
> >>
> >> Cheers,
> >>
> >> Olivier
> >>
> >> --
> >> know that it is solved:
> >>
> >>
> >>
> >> If you still need help, you can reply to this email or go to the
> >> following page to enter your feedback:
> >>
> >>
> >
> > --
>
> --
> know that it is solved:
>
>
> If you still need help, you can reply to this email or go to the
> following page to enter your feedback:
>
>

 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-08-27: #5

Hi,

I do not need the model actually, you should be able to look yourself if you do have additional diagram or not.

Cheers,

Olivier

> On 27 Aug 2021, at 22:40, said ghourmin <email address hidden> wrote:
>
> Question #698539 on MadGraph5_aMC@NLO changed:
>
>
> said ghourmin is still having a problem:
> My model is 123 model, tomorrow i will attach my code and have a look if
> you are available if not intel monday, cuz now i let my machine in
> university
>
> Le ven. 27 août 2021 à 21:30, Olivier Mattelaer <
> <email address hidden>> a écrit :
>
>>
>>
>> Olivier Mattelaer proposed the following answer:
>> Hi,
>>
>> I mean that in the param_card you have to provide the value of the total
>> width for all particle and that all those total width need to be consistent.
>> We do not use branching ratio so we do not need the partial width
>> information. (even if you need to compute those in order to have the total
>> width).
>>
>> For the diagram, you have to look at the diagram generated, I do not
>> know your model so i have no clue if this happens in your case or not.
>>
>> Cheers,
>>
>> olivier
>>
>>> On 27 Aug 2021, at 22:15, said ghourmin <
>>>
>>> Question #698539 on MadGraph5_aMC@NLO changed:
>>>
>>>
>>> said ghourmin is still having a problem:
>>> Do you mean that i don't set the widths of h++ > l+l+ in my code
>> where(l=e
>>> mu tau), and i don't understand what you mean by additional diagram,
>>> because when i have added the lepton final stage other diagram are added
>>>
>>> Le ven. 27 août 2021 à 21:01, Olivier Mattelaer <
>>> <email address hidden>> a écrit :
>>>
>>>>
>>>>
>>>> Olivier Mattelaer proposed the following answer:
>>>> The most likely reason is that you did not set the width of the
>> particles
>>>> to their LO value.
>>>> Note that we have a FAQ on this type of disagreement.
>>>>
>>>> Otherwise, this might also be due to the presence of additional
>>>> diagram/...
>>>>
>>>> Cheers,
>>>>
>>>> Olivier
>>>>
>>>> --
>>>> know that it is solved:
>>>>
>>>>
>>>>
>>>> If you still need help, you can reply to this email or go to the
>>>> following page to enter your feedback:
>>>>
>>>>
>>>
>>> --
>>
>> --
>> know that it is solved:
>>
>>
>> If you still need help, you can reply to this email or go to the
>> following page to enter your feedback:
>>
>>
>
> --

 Revision history for this message said ghourmin (saidghourmin) said on 2021-08-28: #6

Hi,
sorry, i don't know what you mean by additional diagram, is it diagram have no relation with the process or what. And how i can fix the problem of additional diagram

 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-08-28: #7

Hi,

Did you check the Feynman diagram generated by MadGraph?
If you have diagram in your second syntax that does not have equivalent with the one of your frist syntax then you do have additional diagram, (and they are likely nothing to fix).

Cheers,

Olivier

> On 28 Aug 2021, at 11:25, said ghourmin <email address hidden> wrote:
>
> Question #698539 on MadGraph5_aMC@NLO changed:
>
>
> said ghourmin is still having a problem:
> Hi,
> sorry, i don't know what you mean by additional diagram, is it diagram have no relation with the process or what. And how i can fix the problem of additional diagram
>
> --

 Revision history for this message said ghourmin (saidghourmin) said on 2021-08-28: #8

Hi,
the first syntax is pp > z|a > h++ h-- MG5 have generated two diagram but the second when i add four leptonic state pp> z|a >h++h-- > l+l+l-l- its clear that clear that other will generated, is that what you mean by addional diagram

 Revision history for this message Olivier Mattelaer (olivier-mattelaer) said on 2021-09-10: #9

yes,

So you do have additional diagram and therefore they might be the reason of the increase of the cross-section.

Olivier