Diagrams with fermion number violation (Majorana fermions)

Hi,

I'm not sure to understand your problem/questions.

Do you want to create a new model? With a new lorentz structure?
If so the current references to do that is to look at the UFO paper.
e-Print: arXiv:1108.2040 [hep-ph]

In short, you need to create your own model, where you add the related
particles/interactions.
(You might also want to use Feynrules in order to create this model
from the Lagrangian)

Cheers,

Olivier

On 05-avr.-12, at 14:41, Daniel Stolarski wrote:

> New question #192767 on MadGraph5:
> https://answers.launchpad.net/madgraph5/+question/192767
>
> I would like to generate diagrams with naive fermion number
> violation. Namely, a diagram with a Majorana fermion internal line
> which requires a mass insertion. One possible example is, in the
> MSSM, squark pair production with a t-channel gluino exchange. I
> noticed that this is actually figure 2 of the MG manual, but I can't
> see anywhere in the manual where it says how to generate this
> diagram, and all my naive attempts have failed.
>
> Any help would be appreciated!
>
> --
> You received this question notification because you are a member of
> MadTeam, which is an answer contact for MadGraph5.

Hmm...sorry for not being clear in my first email, I was trying to be somewhat generic, but I'll state more explicitly what I want to do.

I would like to, in the MSSM, generate squark pair production and include the diagram which has a t-channel gluino exchange. When I try to generate q \bar q -> squark antisquark, it gives me diagrams with intermediate gluons, W's, and Z's, but no diagram with an intermediate gluino.

Dear Daniel,

I have just tried on the web:

u u~ > ul ul~

and it works fine: there are two diagrams in QCD, one of which
features gluino exchange in the t-channel (Needless to say, you
need to choose the same flavor for the initial state quarks and
final state squarks as the gluino is no flavor-changing).

Cheers

Fabio

On 06 Apr 2012, at 00:55, Daniel Stolarski wrote:

> Question #192767 on MadGraph5 changed:
> https://answers.launchpad.net/madgraph5/+question/192767
>
> Status: Answered => Open
>
> Daniel Stolarski is still having a problem:
> Hmm...sorry for not being clear in my first email, I was trying to be
> somewhat generic, but I'll state more explicitly what I want to do.
>
> I would like to, in the MSSM, generate squark pair production and
> include the diagram which has a t-channel gluino exchange. When I try
> to generate q \bar q -> squark antisquark, it gives me diagrams with
> intermediate gluons, W's, and Z's, but no diagram with an intermediate
> gluino.
>
> --
> You received this question notification because you are a member of
> MadTeam, which is an answer contact for MadGraph5.