MadGraph5_aMC@NLO

elastic scattering

Asked by Wang Daohan

Dear experts:
Sorry to bother you, I was wondering that is it possible to calculate elastic scattering cross section in MadGraph ?
I was trying to do that. The process is the following e- p > e- p(t channel). The mediator is an axion-like particle. The incident electron beam energy I put 0.2 GeV, p is at rest 0 (0.938GeV). I set lpp=0 for the electron beam. As for the proton, no matter if I set lpp=1 or lpp=0, the output is always
Survey return zero cross section.
   Typical reasons are the following:
   1) A massive s-channel particle has a width set to zero.
   2) The pdf are zero for at least one of the initial state particles
      or you are using maxjetflavor=4 for initial state b:s.
   3) The cuts are too strong.
   Please check/correct your param_card and/or your run_card.

Could you please tell me whether the MadGraph can do this ? Where can I implement the form factor? If not, are there any packages can realize such calculation automatically ?
Thank you very much ! Look forward to your kind reply.

daohan

Question information

Language:
English Edit question
Status:
Solved
For:
MadGraph5_aMC@NLO Edit question
Assignee:
No assignee Edit question
Solved by:
Olivier Mattelaer
Solved:
Last query:
Last reply:
Revision history for this message
Best Olivier Mattelaer (olivier-mattelaer) said : 		#1

Hi,

You need for that a specific model where you have the proton as a fundamental particles.
This is not the case in most UFO model but you can certainly have a model where this is defined.
Then when you defined your UFO model you will have the opportunity to specify your own lorentz structure within the UFO model.

Cheers,

Olivier

> On 19 Aug 2021, at 04:11, Wang Daohan <email address hidden> wrote:
>
> New question #698423 on MadGraph5_aMC@NLO:
> https://answers.launchpad.net/mg5amcnlo/+question/698423
>
> Dear experts:
> Sorry to bother you, I was wondering that is it possible to calculate elastic scattering cross section in MadGraph ?
> I was trying to do that. The process is the following e- p > e- p(t channel). The mediator is an axion-like particle. The incident electron beam energy I put 0.2 GeV, p is at rest 0 (0.938GeV). I set lpp=0 for the electron beam. As for the proton, no matter if I set lpp=1 or lpp=0, the output is always
> Survey return zero cross section.
> Typical reasons are the following:
> 1) A massive s-channel particle has a width set to zero.
> 2) The pdf are zero for at least one of the initial state particles
> or you are using maxjetflavor=4 for initial state b:s.
> 3) The cuts are too strong.
> Please check/correct your param_card and/or your run_card.
>
> Could you please tell me whether the MadGraph can do this ? Where can I implement the form factor? If not, are there any packages can realize such calculation automatically ?
> Thank you very much ! Look forward to your kind reply.
>
> daohan
>
> --
> You received this question notification because you are an answer
> contact for MadGraph5_aMC@NLO.

Revision history for this message
Wang Daohan (dorhand) said : 		#2

Thanks Olivier Mattelaer, that solved my question.